http://www.sprint-electric.com/ Sprint Electric - DC Motor Control Technology en-us Copyright 2010 Sprint Electric Sonomatic Ltd. manufactures a number of specialised non-destructive scanners. They have used the Sprint Electric 200XLV low voltage linear DC drive to improve the accuracy of their Nautilus scanner. The Nautilus scanner is a diver-deployed automated ultrasonic system that can operate in depths of up to 250 metres. The Nautilus scanner is designed to adapt to an in-situ mineral or gas pipe junction, or an existing pipe to monitor the quality of a new weld, or the condition of an existing pipe. These can be on land, shipboard or sub-sea. The sub-sea applications present the most demanding technical conditions. Sonomatic has developed technology to overcome the difficult task of adding a new pipe junction (hot tap) to oil and gas pipelines on the sea bed. A habitat is constructed around the hot tap site, approximately the size of a transportation container. The habitat is filled with a mixture of helium and oxygen to allow the divers to enter and work in a dry environment. The divers can work up to 150 metres under water, so providing these habitats is a major achievement itself. With the Nautilus scanner fitted to the hot tap, Sonomatic technicians carry out inspection and analysis using Sonomatic’s Microplus Digital Imaging System. Data is sent from the Nautilus scanner to the technicians through a 250 metres long umbilical cable. The data allows accurate mapping and analysis of the condition of the new pipe junction’s weld. Sonomatic chose the Sprint Electric 200XLV linear drive to provide the low voltage DC control for the Nautilus’ axis motors. Typically one motor would drive the circumferential axis to track around the pipe; the other would drive the axial axis which moves the scanner head in and out whilst rotating around the pipe. The 200XLV was chosen because of its low noise signature. The low level electrical signals produced by the scanner make them very susceptible to electrical interference, especially when the signal cables are alongside power cables in the umbilical cable bundle. The 200XLV reduces the need for heavy filtering of the drive and motor cables over conventional PWM devices. Sprint Electric’s 200XLV is a miniature, fast response DC motor speed controller typically used for driving brushed DC motors, gear-motors, low inductance printed motors and linear actuators rated up to 100W. It is ideal for low power applications such as robotic control and antenna or security camera drives that rely on an unregulated DC or battery supply up to 48V. Offering high bandwidth and a superbly linear, noise free output, the 200XLV is ideal for control of linear actuators. Despite measuring just 40 mm wide, 82 mm high and 50 mm deep, the 200XLV is a genuine four quadrant drive that can motor and brake in both directions of rotation to offer outstanding control of motor speed and torque. Digg this // Bookmark this on Delicious // Subscribe for newsletter updates http://www.sprint-electric.com/news.php?view=9 admin@sprint-electric.com Fri, 12 Dec 2008 14:05:22 GMT While recent advances in AC variable speed drives have improved their performance, the inherent strengths of DC drives mean they still provide the best solution for many industrial applications. For simple, high volume applications such as the control of fans, pumps and compressors, AC variable speed drives represent an excellent and energy efficient solution. At the other end of the scale, AC drives offer far greater bandwidth due to their higher carrier modulating frequency and the forced commutation of the IGBTs. If the application requires a very rapid transient response similar to that offered by servo or motion control drives then the AC drive might be a more appropriate solution. However, DC drive systems remain a highly effective solution for the majority of motor speed control applications. Here, higher bandwidth controllers can cause mechanical resonances and so create more problems than their increased speed of response solve. It is not uncommon for a perceived drive bandwidth problem to be actually a design, wiring or installation defect, and a DC drive equipped with a good quality current control loop can easily satisfy the requirements of most industrial applications. Many engineers wrongly regard DC systems as outdated because of the myths surrounding them but in reality, modern DC drives are at the forefront of variable speed drive technology. Easy to use configuration and diagnostic software tools make setting up today’s DC drives quick and simple, and a range of networking and communications options are available. DC motors are also perceived to be more expensive to install and maintain than a standard squirrel-cage induction motor, because of their brushgear and commutators. In fact, evidence suggests brush wear in DC motors is no longer a major problem. The latest generation of DC motors offer brush service life of 20,000 hours or more - similar to the life of AC motor bearings. While off-the-shelf AC induction motors may have a lower purchase cost, they usually require special fan-cooling arrangements if they are to achieve similar low speed control to DC. This is often vital in applications such as wire drawing or other situations where the drive is required to maintain tension on a winder or drum. In industries such as plastics, steel or paper where precise control of starting as well as running torque is often necessary, a position transducer (encoder) is also required on the shaft of the induction motor. This undermines the principle of the low cost AC motor. A DC drive is capable of operating with in-built armature voltage feedback eliminating the cost of external speed transducers (tachs, encoders, etc) and also increasing the robustness and reliability of the installation. It can also automatically revert to armature voltage feedback in the event of a failure in the primary speed transducer (tach or encoder). The AC drive relies on a position encoder for flux control and some means of speed measurement for speed control, normally combined inside the same housing. It can offer an equivalent mode to the DC armature voltage control by employing sensorless algorithms, but the quality of control is usually inferior and is dependent on the sophistication and the tuning of these algorithms. In comparison, DC motors are very competitively priced, especially in the middle power range between 10 and 250 kW and, taking into account the lower cost of the drive itself, the total DC package can comfortably beat the AC motor plus inverter package on price. The relative small size of a DC drive compared to an inverter drive is also an important factor. The DC drive has only one bridge between the supply and the load, whereas the inverter has a rectifier followed by a DC link storage capacitor and finally the PWM bridge. This results in higher dissipation and a much larger product for a given power rating for the inverter. In multi drive systems it can have a considerable bearing on the costs of the installation. A standard 4-quadrant DC drive is able to motor and brake in both directions of rotation, with the energy generated under braking returned into the mains. Unlike the AC drive, this regenerative braking is achieved without the need for intermediate storage, resistive dumping or an additional power bridge, resulting in reduced energy consumption, faster response to speed transients and no drive trips due to over-voltage. This makes DC the most cost effective and safely controllable solution for applications with overhauling loads such as cranes and hoists, where the motor’s ability to hold full load at zero speed means mechanical brakes may not be required for control purposes. For general applications, the accurate motor control across the speed range, ease of motor tuning and energy efficiency of the DC drive puts it ahead of the more complex AC inverter. This is because in a DC system torque is generated by the linear interaction of the two magnetic fields of the armature winding and the field winding. The commutator ensures that the axes of these magnetic fields are constantly kept perpendicular to each other, in the optimum torque producing position. The resultant torque is practically a linear function of the two DC armature and field currents and the heat dissipation in the windings at a given torque will be constant at any speed (including zero), so special cooling arrangements are not required. In contrast, the AC induction motor develops torque by exciting the stator winding which, in turn, induces slip frequency currents in the rotor cage. The two magnetic field axes are at a variable angle dependent on the shaft and slip angles. Hence, the resultant torque becomes a complicated function of applied voltage, frequency, rotor resistance and slip. Torque can only be produced as long as there is slip (ie the difference between the synchronous and the shaft speeds). The proportion of the total power transferred across the air-gap from the stator that is converted into mechanical power is (1-s), with the rest (s) dissipated as rotor-circuit copper loss. At or near zero speed, a disproportionate amount of power is dissipated as heat as the slip approaches unity, hence the need for costly fan-cooling arrangements for induction motors driven by vector controllers. This also results in higher operating energy costs for the inverter. The tuning of a DC drive is very straightforward compared with the complex procedures required for a flux vector AC unit. DC drive tuning is achieved with the motor stationary, without the need for decoupling of the gearbox or load, and is a one-off procedure without the need for iteration. The accuracy of the tuning process only affects the optimum performance of the drive, and the sensitivity of the drive settings is relatively low. The drive will turn a motor shaft safely under control even with the default power-up control gains, and this is one of the main user-friendly features of the DC drive. The complexity of AC vector control is higher than the DC control and as a result the tuning process is far more complicated and parameter sensitive. In order to implement the vector control calculations it is necessary to have knowledge of the motor magnetising current at different speeds and the rotor time constant. These are the main parameters that the autotune process tries to derive along with some other motor impedance, such as stator resistance and total leakage inductance. In order to estimate the magnetising characteristic the motor has to be rotated up to its maximum speed setting and it also needs to be decoupled from the gearbox and load. Furthermore, it is an iterative process since the value of the rotor resistance has a direct effect on the magnetisation values and vice versa, and it also varies with temperature. It is not uncommon to have to repeat the process several times. Both DC and AC drives provide a good solution for many variable speed control applications. The best choice in each individual case depends on various factors, as different applications place different weight on each performance criterion. So, rather than automatically going down the AC route, proper consideration should be given at the outset to the strengths of DC drives. Subscribe for news updates by email // Digg this http://www.sprint-electric.com/news.php?view=15 admin@sprint-electric.com Fri, 13 Mar 2009 16:01:23 GMT Digital DC drives are now able to control DC motors up to 2250Amps http://www.sprint-electric.com/product_updates.php?pid=17&pu=3 admin@sprint-electric.com Fri, 24 Apr 2009 14:33:12 GMT Sprint Electric Increases Digital DC Drives To 2250Amps Sprint Electric has increased its range of digital DC drives. Both 2Q and 4Q options are now available up to 2250Amps. "This is great news for our customers working in heavy industry" says Gary Keen, Head of Global Sales for Sprint Electric. "We can now work with larger applications in the steel, plastics, rubber, and paper industries." The PL/X range of digital drives offers compact design and powerful software on all models from 12Amps up to the new 2250Amp models. "The compact size, even at the higher power ratings, makes it an attractive option for our retrofit customers". Gary continues, "The savings in cabinet size also help out in a new installation." All models include 40 character alphanumeric backlit displays, a range of software blocks, and a fully controlled field for extended speed range. "As with all our digital products, the software continues to set the standard". Gary explains, "The fully controlled field, the extensive range of software blocks, and the range of communications available, allows our customers to overcome the most demanding of motor control applications." The PLX is UL cUL and CE approved, and is part of an integrated range of analogue and digital dc drives available from stock. http://www.sprint-electric.com/press_releases.php?pid=17&pr=4 admin@sprint-electric.com Fri, 24 Apr 2009 14:33:56 GMT Take control of the most demanding motor control applications. With 2 Quadrant and 4 Quadrant models, you can use the PL/X to control DC motors up to 2250 Amps. High Voltage models are available for supplies up to 690VAC. A 4 button keypad and large alpha-numeric display make it easier to quickly navigate through an extensive range of software functions. The PL/X is fully configurable by the user and comes equipped, as standard, with a comprehensive suite of application blocks. Centre winding macros, spindle orientation and a fully controllable field allow you to control DC motors in a wide range of industrial applications. The PL/X also includes PL Pilot, a windows based, configuration and monitoring software package. The extensive range of motor protection features improves your productivity by reducing your downtime. And the unique configuration checker quickly detects any conflicts in your own user-generated configurations. To make it easier for you to integrate the PL/X into your control system, the drives are fully isolated and have a small footprint. The PL/X has a number of fieldbus communications options, including: Profibus, DeviceNet, CC-Link, EtherNet/IP, Modbus and CANopen. All PL/X models are compatible with drive.web. The drive.web distributed control technology uses Ethernet and powerful graphical tools to provide robust, Programmable Peer Control (PPC) for drives and systems. The drive.web technology is infinitely scalable and cost effective for systems of any size or complexity. For typical motor control systems, drive.web beats using any PLC on cost, performance and ease of use.  http://www.sprint-electric.com/products.php?pid=17 admin@sprint-electric.com Fri, 24 Apr 2009 15:02:40 GMT Working with a worldwide network of partners, Gary ensures you'll always receive prompt and professional service. And with good experience of systems integration and motor applications, Gary can also help you choose the right DC motor controller for your industrial application. http://www.sprint-electric.com/whos_whos.php admin@sprint-electric.com Fri, 3 Apr 2009 10:05:27 GMT You can use this guide to find a replacement for a number of now obsolete single phase DC drives. http://www.sprint-electric.com/datasheets.php?view=18 admin@sprint-electric.com Fri, 5 Jun 2009 15:41:49 GMT A4 brochure of our range of single phase DC motor controllers. Includes - DIN rail mounting and panel mounting options - Isolated and Non-isolated control equipment - 2 Quadrant and 4 Quadrant regen DC Drives. http://www.sprint-electric.com/datasheets.php?view=14 admin@sprint-electric.com Fri, 5 Jun 2009 15:42:19 GMT A4 brochure of our range of three phase DC motor controllers. Includes - Digital and analogue options - 2 Quadrant and 4 Quadrant regen DC Drives. http://www.sprint-electric.com/datasheets.php?view=15 admin@sprint-electric.com Fri, 5 Jun 2009 15:42:47 GMT Easy installation due to top or bottom entry three phase supply input options Standard voltage option 480 VAC max, high voltage option 690 VAC max Sprint Electric has increased its range of digital DC drives up to 2250 Amps (980 KW/1320 HP). All models ranging from 650 to 2250 Amps are offered with two options: Either top entry or bottom entry three phase supply input, and as high voltage (690V AC) or standard voltage (480V AC) models. Available as two quadrant or regenerative four quadrant types, these digital DC drives are ideal for controlling DC motors used in heavy industry applications such as metal working, steel mills, mining, or the cement, rubber and plastics industries. The optional top entry or bottom entry three phase supply input make it easier to install the high power DC drives by giving engineers a choice. For retrofit installations the two options make it easier to use the application's existing cabling; engineers can save time and money by using whichever supply input option is more suitable for their cabling arrangements, instead of adding more expensive copper cable. In new designs, the engineer has the choice of wiring options, which can save money and space when designing new control panels. All models are also offered with a high voltage supply option of 690V AC supplies for use with 750V DC armature motors. Compared to the standard voltage this provides an increase in shaft power, up to 1500 KW/2000 HP for the 2250A model. That is 50 percent more power delivered without an increased cable size. Centre winding macros, spindle orientation and a fully controllable field allow the user to control DC motors in a wide range of applications. The PLX is fully configurable by the user and comes equipped, as standard, with a comprehensive suite of application blocks. A configuration checker quickly detects any conflicts in the configurations generated by the user. And the extensive range of motor protection features improve productivity by reducing downtime. A four button keypad and large alpha-numeric display make it easy to quickly navigate through an extensive range of software functions. The PLX has a number of fieldbus communications options, including: Profibus, DeviceNet, CC-Link, EtherNet/IP, Modbus and CANopen. Increase in accuracy and productivity, and lower energy consumption make DC drives from Sprint Electric ideal for retrofits when a more effective, modern drive system is required. Sprint Electric offers a full range of PLX digital DC drives from 12 Amps up to 2250 Amps, with all models available from stock. Whether in retrofits or original equipment, DC Drives from Sprint Electric are being used in many different applications including metal processing, the pulp and paper industry, rubber and plastic processing, lifting equipment, food processing, leisure industries and many more. Subscribe for newsletter updates // digg this http://www.sprint-electric.com/news.php?view=24 admin@sprint-electric.com Mon, 12 Oct 2009 08:32:48 GMT Learn more about some of the technical terms used on this website. http://www.sprint-electric.com/manuals.php?view=23 admin@sprint-electric.com Mon, 13 Oct 2008 11:48:25 GMT Savvy is a sophisticated software tool that can be used to configure the PL/X as an alternative to PL Pilot. Savvy can be upgraded for a small cost to include a signal flow diagram (SFD) graphical package. This allows the user configured internal block diagram of the PL/X system to be represented as a block diagram on screen and changed by drag and drop connections from PIN to PIN. When used in conjunction with the drive.web distributed control products the Savvy software can produce an entire configuration diagram of a multiple drive system. http://www.sprint-electric.com/products.php?pid=31 admin@sprint-electric.com Mon, 17 Nov 2008 11:41:53 GMT All PL/X models are compatible with Drive.Web. The Drive.Web distributed control technology uses Ethernet and powerful graphical tools to provide robust Programmable Peer Control (PPC) for drives and systems. The Drive.Web technology is infinitely scalable and cost effective for systems of any size and complexity. For typical motor control systems, Drive.Web beats using any PLC on cost, performance and ease of use. http://www.sprint-electric.com/products.php?pid=32 admin@sprint-electric.com Mon, 17 Nov 2008 12:06:35 GMT To ensure you receive your orders on time, every time, Donna looks after our delivery and after sales support. Donna works closely with a few key customers to provide an extra level of support and service. http://www.sprint-electric.com/whos_whos.php admin@sprint-electric.com Mon, 18 May 2009 09:33:06 GMT Manual for 3600XRi DC drive. http://www.sprint-electric.com/manuals.php?view=13 admin@sprint-electric.com Mon, 20 Oct 2008 10:16:14 GMT Manual for 3200i and 1600i DC drives. http://www.sprint-electric.com/manuals.php?view=12 admin@sprint-electric.com Mon, 20 Oct 2008 10:16:44 GMT Manual for 400, 800 and 1200 DC drives. http://www.sprint-electric.com/manuals.php?view=15 admin@sprint-electric.com Mon, 20 Oct 2008 10:17:21 GMT Applications manual for 340i, 680i, 1220i isolated range of DC motor controllers. http://www.sprint-electric.com/manuals.php?view=21 admin@sprint-electric.com Mon, 20 Oct 2008 10:18:23 GMT Manual for 340XRi, 680XRi, 1220XRi. Regenerative, Isolated, DIN rail mounting. http://www.sprint-electric.com/manuals.php?view=10 admin@sprint-electric.com Mon, 20 Oct 2008 10:18:39 GMT Manual for Digital Panel Meters. http://www.sprint-electric.com/manuals.php?view=19 admin@sprint-electric.com Mon, 20 Oct 2008 10:23:15 GMT Applications manual for 340XRi, 680XRi, 1220XRi isolated range of DC motor controllers http://www.sprint-electric.com/manuals.php?view=22 admin@sprint-electric.com Mon, 20 Oct 2008 10:24:38 GMT Manual for 340i, 680i, 1220i range. Isolated, din rail mounting. http://www.sprint-electric.com/manuals.php?view=3 admin@sprint-electric.com Mon, 20 Oct 2008 10:24:52 GMT Manual for 340, 680, 1220 DC drives. Non isolated, DIN rail mounting. http://www.sprint-electric.com/manuals.php?view=11 admin@sprint-electric.com Mon, 20 Oct 2008 10:26:01 GMT Manual for 370 DC drive. http://www.sprint-electric.com/manuals.php?view=16 admin@sprint-electric.com Mon, 20 Oct 2008 10:26:30 GMT Manual for 400i DC drive. http://www.sprint-electric.com/manuals.php?view=14 admin@sprint-electric.com Mon, 20 Oct 2008 10:26:42 GMT Manual for armature Reversing Unit. http://www.sprint-electric.com/manuals.php?view=17 admin@sprint-electric.com Mon, 20 Oct 2008 10:27:10 GMT Manual for 200XLV linear DC drive. http://www.sprint-electric.com/manuals.php?view=18 admin@sprint-electric.com Mon, 20 Oct 2008 10:27:24 GMT Datasheet for 340XRi, 680XRi, 1220XRi DC drives. http://www.sprint-electric.com/datasheets.php?view=6 admin@sprint-electric.com Mon, 20 Oct 2008 10:47:17 GMT Datasheet for 340i, 680i, 1220i DC drives. http://www.sprint-electric.com/datasheets.php?view=5 admin@sprint-electric.com Mon, 20 Oct 2008 10:47:31 GMT 340, 680, 1220 analogue DC motor controller. Din rail mounting http://www.sprint-electric.com/datasheets.php?view=3 admin@sprint-electric.com Mon, 20 Oct 2008 10:47:46 GMT Datasheet for 200XLV linear DC drive. http://www.sprint-electric.com/datasheets.php?view=4 admin@sprint-electric.com Mon, 20 Oct 2008 10:48:04 GMT Datasheet for DPM. http://www.sprint-electric.com/datasheets.php?view=10 admin@sprint-electric.com Mon, 20 Oct 2008 10:48:23 GMT PLA Datasheet http://www.sprint-electric.com/datasheets.php?view=17 admin@sprint-electric.com Mon, 23 Feb 2009 08:47:33 GMT Minimise your set-up and commissioning time. PL Pilot allows you to use a windows based software package to configure your block diagrams and parameters when using the PL/X range of drives. It allows you to configure and monitor motor control applications without any prior knowledge of a programming language. To monitor and adjust your parameters in real time, simply connect your PC, running PL Pilot to the PL/X DC drive through a standard serial port. http://www.sprint-electric.com/products.php?pid=22 admin@sprint-electric.com Mon, 23 Mar 2009 12:23:11 GMT Here are the answers to some of the frequently asked questions we receive relating to the three phase PL/X digital DC drives and the PL Pilot drive configuration software. http://www.sprint-electric.com/datasheets.php?view=16 admin@sprint-electric.com Mon, 23 Mar 2009 15:30:59 GMT this is my first update http://www.sprint-electric.com/product_updates.php?pid=5&pu=2 admin@sprint-electric.com Sat, 26 Jul 2008 14:03:50 GMT To allow you to easily integrate with other drives and control equipment, the 1600i is a fully isolated, single direction DC motor controller. Suitable for systems integrators, panel builders and OEM manufacturers, the compact design makes upgrading your existing control system easy. You will also save space in new designs. http://www.sprint-electric.com/products.php?pid=15 admin@sprint-electric.com Thu, 12 Feb 2009 10:07:45 GMT Available in four current outputs up to 48 Amps, to closely match your motor requirements. To make installation easier, you can quickly connect using screw terminals. Easy to access control terminals, extensive features and I/O make this range of DC motor controllers an industry standard. With line-to-line or line-to-neutral operation up to 48 Amps, you can use this controller in a wide range of motor control applications. You can also integrate this motor controller with other drives and electrical equipment. The 3200i is a fully isolated DC motor controller. http://www.sprint-electric.com/products.php?pid=16 admin@sprint-electric.com Thu, 12 Feb 2009 10:09:27 GMT Make upgrading your existing control panel easier. Save space in new DC single direction motor control systems. The ultra compact DIN rail mounting package lets you install quickly. Three options are available for controlling DC motors up to 12.2 Amps. You can use this versatile range of non-isolated controllers for permanent magnet, shunt wound motors or universal motors. To make your installation quick and simple, all 340, 680, and 1220 series controllers have easy to access drive adjustments, plug-on screw terminals and a small foot print from just 35mm x 105mm. http://www.sprint-electric.com/products.php?pid=27 admin@sprint-electric.com Thu, 12 Feb 2009 10:09:55 GMT Improving or upgrading your single direction DC motor control system is easier with this series of fully-isolated controllers. The ultra compact DIN rail mounting package lets you quickly integrate the 340i, 680i, 1220i series with your existing motor control equipment. Three options are available for controlling DC motors up to 12.2 Amps. You can use this versatile series of fully-isolated controllers for permanent magnet, shunt wound motors or universal motors. To make your installation quick and simple, all 340i, 680i, and 1220i series controllers have easy to access drive adjustments, plug-on screw terminals and a small foot print from just 60mm x 105mm. http://www.sprint-electric.com/products.php?pid=9 admin@sprint-electric.com Thu, 12 Feb 2009 10:11:51 GMT This 4 Quadrant regenerative DC motor controller gives a fast controlled response over the full forward/reverse speed range for motoring and braking. Improve your energy efficiency by regenerating energy into the mains supply whilst under braking. The energy invested accelerating the load mass is recovered when braking. No dissipation of energy in wasteful braking resistors. The compact DIN rail mounting package can save you space as well as energy. Three options are available for controlling DC motors up to 12.2 Amps. You can use this versatile series of fully-isolated controllers for permanent magnet or shunt wound motors. To make your installation quick and simple, all 340XRi, 680XRi, and 1220XRi series controllers have easy to access drive adjustments, plug-on screw terminals and a small foot print from just 60mm x 105mm. http://www.sprint-electric.com/products.php?pid=10 admin@sprint-electric.com Thu, 12 Feb 2009 10:12:17 GMT This 4 Quadrant regenerative DC motor controller gives a fast controlled response over the full forward/reverse speed range for motoring and braking. Improve your energy efficiency by regenerating energy into the mains supply whilst under braking. The energy invested accelerating the load mass is recovered when braking. No dissipation of energy in wasteful braking resistors. With five models up to 36 Amps, you can closely match the power required by your application. The 3600XRi has a robust design and is packed with features to help you reduce your down-time and maintenance costs.  http://www.sprint-electric.com/products.php?pid=13 admin@sprint-electric.com Thu, 12 Feb 2009 10:12:55 GMT SL 2 Quadrant and SLX 4 Quadrant models are compact, reliable and efficient dc motor controllers. The 4Q models improve your energy efficiency by regenerating energy into the mains supply whilst under braking. The energy invested accelerating the load mass is recovered when braking. No dissipation of energy in wasteful braking resistors. With fully isolated control electronics and a wealth of I/O, the SL/X are easy for you to integrate with other drives and equipment. To allow you greater control of high motor speed applications, the SL/X has a built-in field weakener for extended speed range. http://www.sprint-electric.com/products.php?pid=19 admin@sprint-electric.com Thu, 12 Feb 2009 10:13:51 GMT A drive designed specifically for straightforward cost effective control of single direction DC motors up to 106 Amps. The SLE drive offers you reliability and performance when controlling simple dc motor applications --  ideal if you are an OEM or machine builder. The compact size makes it easier to integrate into new designs or existing control systems. http://www.sprint-electric.com/products.php?pid=18 admin@sprint-electric.com Thu, 12 Feb 2009 10:15:32 GMT DC Drives have long been subjected to the notional threat of extinction from experts and non-experts alike. The reasoning goes like this: A DC motor is more expensive compared to a standard squirrel-cage induction motor and it needs maintenance in the brushgear and/or commutator. The DC thyristor controller (“converter”) is operating at a frequency of 6 times the mains frequency (i.e. 300Hz for 50Hz mains supply) and therefore it has a much lower inherent bandwidth compared to an AC controller (“inverter”) with a modulating frequency in the 1 to 10KHz region. These are very compelling arguments indeed, at least until you look a little closer. Anecdotal evidence suggests brush wear is greatly exaggerated and new generation DC motors have improved on brush life, whilst they also provide advance warning for a scheduled brush replacement, if necessary. Market forces have dictated more competitively priced DC motors especially in the middle (10-250KW) power range. If the price of the converter is added to the DC motor, then the total DC package comfortably beats the AC motor plus inverter package. But what about performance, then? Let us break this down to its main features: Torque At Start And Near Zero Speed The DC drive develops full rated torque at or near zero speed in exactly the same way as throughout the entire speed range. This is because torque is generated by the linear interaction of the two magnetic fields of the armature winding and the field winding. The commutator ensures the axes of these magnetic fields are constantly kept perpendicular to each other, thereby in the optimum torque producing position. The resultant torque is practically a linear function of the two d.c. armature and field currents. The heat dissipation in the windings at a given torque will be constant at any (including zero) speed and therefore the cooling arrangements can be easily dealt with in a standard fashion. The converter can also independently set the required current levels in each winding to meet a certain load requirement without the need for complicated algorithms since the interaction between the two is practically zero. The DC motor also offers more flexibility in starting torque characteristics by series, parallel or compound field winding configuration. In contrast, the AC motor needs special cooling arrangements to allow full torque to be developed near zero speed. The reason is fundamental to the workings of an induction motor: An induction motor develops torque by exciting the stator winding, which, in turn, induces slip frequency currents in the rotor cage. The two magnetic field axes are at a variable angle dependent on the shaft and slip angles. Hence, the resultant torque becomes a complicated function of applied voltage, frequency, rotor resistance and slip. Furthermore, torque can only be produced as long as there is slip, i.e. difference between the synchronous and the shaft speeds. Slip is more usually expressed as a fraction of the synchronous speed, i.e. the per-unit slip is: s = (ns - n) / ns where the synchronous speed ‘ns’ is determined by the inverter output frequency ‘f’ and the number of poles ‘P’, i.e. ns = 120f / P in rpm. The proportion of the total power transferred across the air-gap from the stator converted into mechanical power is (1-s), with the rest (s) dissipated as rotor-circuit copper loss. Hence, at or near zero speed a disproportionate amount of power is dissipated as heat as the per unit slip approaches unity. Furthermore, the higher the rotor resistance is, the higher these copper losses will be throughout the speed range. Therein lies a basic limitation of induction motors with constant rotor resistance in as far as the rotor design has to be a compromise: The torque developed, for a given applied voltage, frequency and slip, is proportional to rotor resistance. If the rotor resistance is reduced to incur less copper losses and hence increase efficiency, the starting torque will be lower. This is the penalty paid for frequency control rather than rotor resistance control, which requires a wound rotor with slip rings and brushes. The need therefore for special fan-cooling arrangements for induction motors driven by vector controllers partly defeats the advantage of the “inexpensive standard” induction motor. And the story gets worse... A position transducer (encoder) is also required on the shaft of the induction motor, if precise control of starting (as well as running) torque is necessary, even further undermining the principle of standard motor. Regenerative Breaking The 4-quadrant DC drive offers inherent breaking capability in both directions of rotation with the energy returned back into the 3-phase mains without the need as per AC drive for intermediate storage, resistive dumping or additional power bridge. This results into a three-fold advantage within the standard DC drive package: energy conservation faster response to speed transients no drive trips due to overvoltage. Compact Size And Heat Dissipation The DC motor is usually of an open-frame through-vent construction. This suits the purpose of its applications, since if the environment is explosive, corrosive or of air with high particle density, its use tends to be limited. However, this turns out to be a great advantage in any other normal industrial application in terms of ease of cooling and therefore compactness, i.e. smaller frame size for a given KW rating. Conversely, the AC motor is normally of TEFC (totally-enclosed fan-cooled) construction which places a further burden on the cooling arrangements, particularly in the circumstances explained in item 1 above. The DC converter is also far more compact that the equivalent AC inverter which is due mainly to the fact that there is no need for intermediate energy storage (as per dc link-fed inverter), i.e. no electrolytic capacitor bank and choke, as well as because the thyristor firing circiuts are far simpler and more robust than the gating IGBT circuits. Torque-Speed Curve Characteristics The torque-speed characteristic of a DC drive can easily match any load requirement and it often forms the benchmark for other drives’ performance evaluation. They are naturally divided into constant-torque (armature voltage control) and constant-power (field weakening) regions because of the independence of the two magnetic fields, as explained above. Besides, there is usually an option of different field winding configurations (series, parallel, compound). Some AC vector controllers set out to emulate the full DC range above with varying degrees of success. Torque Ripple And Smoothness Of Control The DC motor naturally produces smooth torque as long as the armature and field currents are smooth. Due to the inductance in the respective windings this is normally easily achieved. If necessary, a choke can be added in series with the armature to reduce the ripple, or alternatively, a 12-pulse control can be employed. The DC drive offers low acoustic noise and excellent controllability. The AC drive is normally acoustically harsher and relies on accurate control action for smoothness of torque. Speed Control With And Without Speed Transducer The DC drive is capable of operating with the in-built armature voltage feedback, albeit at reduced accuracy and bandwidth, thereby eliminating the cost of external speed transducers (tachs, encoders, etc) and also increasing the robustness of the installation. The AC drive, as mentioned above, relies on a position encoder for flux control and some other means of speed measurement for speed control, normally combined inside the same housing. It can offer a kind of equivalent mode to the DC armature voltage control by employing sensorless algorithms. However, the quality of control is usually inferior and it is certainly dependent on the sophistication and the tuning of these algorithms. Transient Response (Bandwidth) The bandwidth in the DC drive is limited by the 300/360Hz mains-effected natural commutation. The AC drive is certainly capable of higher bandwidth due to its higher carrier modulating frequency and the forced commutation of the IGBT’s. In that respect it competes more with the servo systems, if maximum bandwidth is paramount for the application. However, in the general industrial arena, higher bandwidth controllers can cause mechanical resonances and generally create more problems than their increased speed of response can solve. It is not uncommon that a perceived drive bandwidth problem is actually a system design defect, wiring or installation malfunction. A DC drive equipped with a good quality current controller can more than adequately perform in the majority of industrial applications. Component Degradation The DC converter has no vital electronic components that degrade with time, temperature or dv/dt transients. On the other hand, the AC inverter has an electrolytic capacitor bank with diminishing ripple current capability over time and over temperature and power semiconductors (IGBT’s) that can be affected by fast dv/dt cycling. The DC motor brushes and commutator maintenance is well-documented if not somewhat exaggerated. However, the induction motor bearings, insulation and even the rotor cage structure are known to develop problems due to excessive dv/dt and induced currents. RFI Emissions And Filtering The severity of RFI emissions from both control and power ports of a drive is more prominent in the AC rather than the DC drive due mainly to the former’s higher switching frequencies and faster power device turn-on and turn-off. Consequently, the filtering and cable-shielding requirements become more stringent in the AC drive. User-friendliness and Tuning Torque Control Tuning DC Drive Tuning The tuning of a DC drive is relatively straightforward. As already outlined above, the torque is the linear product of the armature and field currents. Therefore, for an optimised torque response one needs to tune separately the armature and the field current loops. This can be done with the motor stationary, without the need for decoupling of the gearbox and/or load and without unnecessary exposure to rotating mass hazards before the full plant commissioning has been safely accomplished. It is also a one-off procedure without the need for iteration neither individually for each loop nor collectively. The armature current loop is a P + I (proportional + integral) controller with some adaptive correction for the discontinuous current mode of operation, as per Fig. 1. The reason for the simplicity of this algorithm, is the simple transfer function of the armature circuit, i.e. a fixed resistance (R) and a fixed inductance (L) in series. In the continuous current mode the P and I gains dictate the transient response. The integral gain should be increased from a low value upwards to give a slightly overshooting response and then the proportional gain should be increased upwards until the damping of the transient response returns to nearly critical, i.e. settling without appreciable overshoot or oscillation. It might be necessary when the response is roughly in the correct region to further re-adjust the integral gain slightly up or down and similarly re-adjust the proportional gain in order to tune the damping more finely towards the optimum critical value. If optimum response is to be achieved from zero current through the entire range, then the discontinuity boundary DISC (the percentage of full load current where the current starts to be continuous) needs to be established. This is easily achieved by an autotuning process, or even manually by gradually increasing the armature current from zero until continuity is observed on an oscilloscope. Similarly, the autotune process will set the P and I gains or a manual trial and error procedure, as outlined above, can very easily achieve the same. These three parameters, P, I and DISC, totally define the performance of the armature current loop and therefore the torque bandwidth. The field current loop controller is similarly a P + I controller which operates in the continuous current mode because of the large field winding inductance. Hence, only the P and I gains need to be set for the field which are of less importance from the torque transient response point of view, since normally only very small perturbations occur around the full field current reference point. If field weakening is required, then the P and I tuning has to be more vigorous and, in addition, tuning of the PID (proportional+integral+differential) armature voltage controller is then necessary. It is important to note that the accuracy in the setting of the above parameters will only affect the optimum performance of the drive. However, the sensitivity of this setting with respect to the optimisation level is relatively low. Furthermore, it will not prevent the drive from turning a motor shaft safely under control even with the default power-up control gains. This will also be true for a wide range of motor horsepower ratings and it constitutes one of the main user-friendly features of the DC drive. AC Drive Tuning Whereas in the DC drive the term current control is tantamount to torque control and so, as outlined above, essentially only one control loop tuning is necessary, in contrast in the AC drive torque and flux demand control loops have to operate additionally in order to set the correct demand level for the current controller, see Fig. 2. The torque control in an induction motor (often referred to as ‘vector control’) consists of the following parts: Read the stator phase currents I1 and I2. It is only necessary to sample only 2 out of the 3 stator currents, as the sum of all three is zero. Read shaft encoder angle and estimate slip angle in order to derive rotor flux angle. Using rotor flux angle, resolve I1 and I2 to id and iq, where id is in-line with the rotor flux axis and iq is at 90 degrees. Hence, id controls the rotor flux magnitude and iq controls the slip and therefore the torque. Estimate rotor flux magnitude imr from stator feedback id and rotor time constant. Derive required id* demand through a P + I controller operating on rotor flux error. Derive required iq* demand from the ratio of torque demand over rotor flux. Update rotor flux angle. Using rotor flux angle, convert stator current demands id* and iq* into stator phase current demands I1*, I2* and I3*. Setup three P + I current controllers to drive the power bridge which produces the three sinusoidal motor currents. Compare this with the R,L model of the DC motor armature and it becomes obvious that the complexity of the vector control is orders of magnitude higher than the DC control. As a result, the tuning process is far more complicated and parameter sensitive. In order to implement the vector control calculations it is necessary to have knowledge of the motor magnetising current at different speeds and the rotor time constant. These are the main parameters the autotune process tries to derive along with some other motor impedances such as stator resistance and total leakage inductance. In order to estimate the magnetising characteristic the motor has to be rotated up to its maximum speed setting and it also needs to be decoupled from the gearbox and load. This incurs both inconvenience and exposure to hazards as shaft rotation is effected right at the beginning of the commissioning process. Furthermore, it is very much an iterative process since the value of the rotor resistance has a direct effect on the magnetisation values and vice versa. A further complication arises from the fact that the value of the rotor resistance varies with motor temperature and therefore some compensating algorithm has to be added to track this change against temperature. If the autotune process is performed on a cold motor, the results are likely to be less accurate. So it is not uncommon to have to repeat the process several times and not necessarily with repeatable results. In other words, vector tuning tends to be a bit of a ‘black art’ even for reasonably skilled drive commissioning engineers. Speed Control Tuning The speed loop tuning is very similar for both DC and AC drives. It is usually a P I controller (sometimes PID) and the setting of the P and I terms has to take place with the actual transmission system and the ‘typical’ load connected to the shaft. The procedure for tuning the speed PI controller is very similar with that outlined earlier for the armature current PI controller. The integral gain needs to be lower for higher motor/load inertias and it also controls the steady-state error and therefore the long term speed hold accuracy. More often this tuning is a manual trial and error process in order to yield the best results for the particular operating conditions of the plant at a given application. However, some drives provide an autotune facility for the speed loop by rotating the motor and load at particular speeds and estimating the frictional and inertial components. Conclusion Both DC and AC drives provide a good solution to variable speed control applications. What the particular choice is in each individual case depends on various factors, some of which were given a brief overview above. It would not be constructive or fair to place a rigid selection chart on the subject as different applications dictate different weighting factors on each performance criterion and therefore the wise thing always remains...horses for courses. Subscribe to receive more DC motor control news // Digg this http://www.sprint-electric.com/news.php?view=16 admin@sprint-electric.com Thu, 12 Feb 2009 12:14:20 GMT Sprint Electric has increased its range of digital DC drives further. Both 2 Quadrant and 4 Quadrant options are now available up to 1850Amps. The new drives will be introduced in November at SPS/IPC/Drives, the international trade fair for electric automation, systems and components, in Nuremberg, Germany. “This is more great news for our customers working in heavy industries like paper, plastics and metals,” says Gary Keen, Head of Global Sales for Sprint Electric. “We saw our customers had great success when we recently increased the power rating of our digital DC drives to 1050 Amps. So we can understand why they are pleased to hear we have increased our power ratings again.” The PLX range of digital drives offers compact design and powerful software on all models from 12Amps up to the new 1850Amps models. All models include 40 character alphanumeric backlit displays, a range of software blocks, and a fully controlled field for extended speed range. “As with all our digital products, the software continues to set the standard”, Gary explains. “The fully controlled field, the extensive range of software blocks, and the range of communication protocols available allow our customers to overcome the most demanding of motor control applications.” The PLX is UL, cUL and CE approved and available from stock. The PLX is part of an integrated range of analogue and digital DC drives covering both single phase and three phase, regenerative and non-regenerative applications. Whether in original equipment or in retrofits, DC Drives from Sprint Electric are being used in many different applications including the metal processing industry, the pulp and paper industry, rubber and plastic processing, lifting equipment, food processing, Leisure industries and many more. Digg this // Subscribe for newsletter updates http://www.sprint-electric.com/news.php?view=13 admin@sprint-electric.com Thu, 12 Feb 2009 12:17:22 GMT Do you know over 375 Million US dollars will be spent on DC drives around the world this year? So obviously, there are applications where DC technologies continue to be the best option. But what are they? Here's a guide to help you. Learn more about the: Processes and applications where DC drives are used Typical power ratings Type of control you need Useful tips for each application Download your guide here. (pdf. 207KB) Print it. Share it. Use it. And make it easier to choose the right DC drive. Read other DC drive news here // Subscribe to the DC drives newsletter here http://www.sprint-electric.com/news.php?view=17 admin@sprint-electric.com Thu, 12 Feb 2009 14:35:18 GMT No doubt you'll already know we introduced a new series of PL/X DC digital DC drives at SPS/IPC last month; You can now use the PL/X to control DC motors up to 1850 Amps. The increase in power means you'll be able to overcome the demands of more and more DC motor applications. And to help you out, I've put together a list of digital DC drive FAQs (with some help from Jim, our Technical Support Manager). In the pdf you'll find answers to 32 of the questions we get asked about the PL/X and PL Pilot - its monitoring and configuration software. Click here to download your copy - Digital DC Drive FAQs (pdf - 175kb) Print it. Share it. Use it. And make it easier to choose the right DC drive Read other DC drive news here // Subscribe to the DC drives newsletter here http://www.sprint-electric.com/news.php?view=18 admin@sprint-electric.com Thu, 12 Feb 2009 14:38:15 GMT Over the past couple of months we've talked a lot about our digital DC drives. With power ratings up to 1850 Amps, it's got most of the larger DC motor applications covered. But what about the smaller DC motor applications? How do you control the small motors used to position security cameras or those used to control the axis on an XY table? Here are some links to help you: - Learn how the 200xlv was used to control non-destructive scanners on the bottom of the ocean. (pdf 151KB) - Visit the 200XLV page on our website for full technical specifications. Read other DC drive news here // Subscribe to the DC drives newsletter here http://www.sprint-electric.com/news.php?view=19 admin@sprint-electric.com Thu, 12 Feb 2009 14:42:05 GMT See how easily you can retrofit DC motor controllers. The compact sizes mean they will always fit in the the availabe space. http://www.sprint-electric.com/datasheets.php?view=13 admin@sprint-electric.com Thu, 16 Oct 2008 14:10:34 GMT Do you need to choose a DC drive to fit your industrial application? Or do you have a DC drive you need some help setting up correctly? Jim will help you. With over 20 years experience with DC drives and industrial motor applications, Jim will provide you with advice, know-how and support http://www.sprint-electric.com/whos_whos.php admin@sprint-electric.com Thu, 28 Aug 2008 10:21:52 GMT A quick product showreel. http://www.sprint-electric.com/video_tutorials.php?view=3 admin@sprint-electric.com Thu, 28 Aug 2008 15:27:50 GMT Mill Court, Isle of Wight, gb, PO30 2AA http://www.sprint-electric.com/partners.php?view=1 admin@sprint-electric.com Thu, 31 Jul 2008 11:40:23 GMT For your applications where you require a battery or unregulated DC source. The 200xlv will motor and brake in both directions of rotation. Able to fit in the palm of your hand, this DC motor controller is ultra compact. A cost effective way for you to control small low voltage brushed DC motors or gearmotors up to 48 Volts. Provision for back panel or DIN rail mounting means you can install quickly. And Plug-in screw terminals make it easier to use. This model is ideal for installations that require low electrical noise operation. e.g. security cameras,  XY tables. http://www.sprint-electric.com/products.php?pid=20 admin@sprint-electric.com Thu, 7 May 2009 12:48:47 GMT Manual for IP20 metal enclosure. http://www.sprint-electric.com/manuals.php?view=20 admin@sprint-electric.com Thu, 7 May 2009 14:50:34 GMT Manual for SLE analogue DC drives. http://www.sprint-electric.com/manuals.php?view=9 admin@sprint-electric.com Thu, 7 May 2009 15:01:55 GMT Manual for SL analogue DC drives http://www.sprint-electric.com/manuals.php?view=37 admin@sprint-electric.com Thu, 7 May 2009 15:02:07 GMT Manual for SLX analogue DC drives. http://www.sprint-electric.com/manuals.php?view=8 admin@sprint-electric.com Thu, 7 May 2009 15:02:18 GMT PLXD Stack driver manual http://www.sprint-electric.com/manuals.php?view=34 admin@sprint-electric.com Thu, 7 May 2009 15:02:31 GMT PL/X Serial Comms Manual http://www.sprint-electric.com/manuals.php?view=33 admin@sprint-electric.com Thu, 7 May 2009 15:02:48 GMT Manual for PL/X digital DC drive. http://www.sprint-electric.com/manuals.php?view=7 admin@sprint-electric.com Thu, 7 May 2009 15:02:58 GMT Datasheet for SLE DC drives. http://www.sprint-electric.com/datasheets.php?view=8 admin@sprint-electric.com Thu, 7 May 2009 15:03:45 GMT Datasheet for SL/X range of analogue DC drives. http://www.sprint-electric.com/datasheets.php?view=9 admin@sprint-electric.com Thu, 7 May 2009 15:03:56 GMT Brochure for PL/X digital DC drives. http://www.sprint-electric.com/datasheets.php?view=7 admin@sprint-electric.com Thu, 7 May 2009 15:04:08 GMT PL/PLX datasheet http://www.sprint-electric.com/datasheets.php?view=2 admin@sprint-electric.com Thu, 7 May 2009 15:04:27 GMT Manual for PLA Applications Module http://www.sprint-electric.com/manuals.php?view=5 admin@sprint-electric.com Thu, 9 Apr 2009 16:52:21 GMT Compare the digital DC drives from 5 leading drives manufacturers. http://www.sprint-electric.com/datasheets.php?view=11 admin@sprint-electric.com Thu, 9 Oct 2008 10:19:08 GMT This guide covers most of the industries and applications where DC drives are used. http://www.sprint-electric.com/datasheets.php?view=12 admin@sprint-electric.com Thu, 9 Oct 2008 10:22:23 GMT In case you missed the stories in the media, A serious UK-based AC drive manufacturer has spent a great amount of time and money to show you the DC drive market is alive and well. According to the headlines, DC drives can offer you lower costs, fewer risks and significant advantages over AC drives in many applications. Here are the best bits from an article in Industrial Technology magazine... "...In any industry, there will always be strong motivations to upgrade equipment if it can improve throughput and product quality, reduce waste and operating costs and integrate equipment into information networks. But these have to be balanced against on return on investment, the downtime of the plant, the implications of retraining staff, and of course space constraints. And what this UK-based AC drive manufacturer has found, time and again, is where there is an installed DC system, upgrading it with a new DC drive system means a lower overall cost and risk. At higher powers, the drive itself will usually be cheaper than an AC equivalent, and in some cases so will the motor. But if you already have an installed DC system, there is no need to replace the motor or any other components in the power train: the cost of switching to AC power, by contrast, means throwing away all that existing investment. DC control concepts are simple and well understood, so the implications for retraining are minimised. And finally the size of a higher power DC drive is significantly smaller than an AC equivalent, delivering big savings on panel real estate. DC drive systems are here to stay for the foreseeable future, with opportunities for plant upgrades in many industries and in all regions of the world representing a significant market..." As you can see - DC Drives are here to stay. And like you, we've known this all along. So we'll continue to make it easier for you to take control of the most demanding motor control applications with DC drives. Subscribe for news updates by email // Digg this http://www.sprint-electric.com/news.php?view=14 admin@sprint-electric.com Tue, 10 Feb 2009 13:00:26 GMT Sprint Electric Ltd., manufacturer of DC drives, received a Royal visitor on 9 September when Prince Edward, The Duke of Kent, came to the company’s premises in Ford near Arundel, West Sussex, to present the firm with a Queen’s Award for Enterprise for its outstanding business success. Sprint Electric won the Queen’s Award in the International Trade category in April this year. A special reception for the Queen’s Award winners was held in Buckingham Palace on 13 July, hosted by Her Majesty The Queen and other members of the Royal Family. At the presentation ceremony, Sprint Electric was presented with a crystal bowl engraved with The Queen’s Awards Emblem as a symbol of its success as well as a grant of appointment. The company is now also entitled to use the Emblem in all its marketing and on packaging for the next five years, here and abroad. Sprint Electric designs and manufactures industrial motor controllers, specialising in DC drive technology. With an export share of approximately 75 percent, the products are sold worldwide. Sprint Electric’s Managing Director Edwin Prescott explains, "The Queen’s Award for International Trade is a result of our sustained export growth measured over the last six years. We are planning for further growth and are confident of enjoying continued success over the next six years and beyond." Sales Director Gary Keen continues, "Our success also owes a great deal to our overseas distributors. Every distributor is offered full training at our offices, so they can support our DC drives in any industrial application. Because we design and build the complete range of products at our Arundel site, we can be very responsive to our customers. Being able to ship our DC drives immediately means our customers receive their orders quickly – regardless of where they are in the world.” Founded in 1987, Sprint Electric offers over fifty models of motor controllers, from low voltage servo performance controllers to fully digital three phase DC variable speed drives of many hundreds of amperes. Whether in retrofits or original equipment, DC Drives from Sprint Electric are being used in many different applications including metal processing, the pulp and paper industry, rubber and plastic processing, lifting equipment, food processing, leisure industries and many more. The Queen’s Awards for Enterprise exist to champion the UK’s most enterprising, creative and sustainable organisations – from all business sectors. Companies can apply for an Award in three categories – International Trade, Innovation or Sustainable Development. The Awards are open to any UK-based business with two or more employees. subscribe for more news // digg this http://www.sprint-electric.com/news.php?view=23 admin@sprint-electric.com Tue, 15 Sep 2009 18:31:45 GMT Electric motors are more vulnerable to suffer electrical erosion in bearings when controlled by AC variable frequency drives – a problem not suffered by dc drives Motor shaft voltages that discharge to earth through a bearing can cause electrical erosion, lubricant degradation and, ultimately, bearing failure. The increasing use of AC variable frequency drives has made the problem more severe and widespread. AC variable frequency drives can induce currents that increase until they find a path to earth via the motor frame. These currents can pass through the bearings and, when the voltage is high enough to overcome the lubricant layer, discharges occur, damaging the surfaces of the rolling elements and raceways. This cause of motor failure has become an increasingly important reliability issue and the prevention of bearing failure in AC variable frequency driven motors is an important design consideration to ensure motor reliability and to reduce operating costs. AC variable frequency drives induce destructive voltage on the motor shaft until an alternate discharge path, usually the motor’s bearings, is found to discharge the voltage to ground. Inside the bearing, once voltage is sufficient to exceed the breakdown potential of the oil film layer, bearing currents cause an electrical discharge machining (EDM) effect, which pits the bearing race and rolling elements. This destructive phenomenon continues until the motor bearings become so severely pitted that fluting occurs. This causes excessive vibration and noise in the motor and finally, motor failure occurs. The root cause of bearing current discharges that damage motor bearings is the high speed switching from pulse width modulation (PWM) drives that use insulated gate bipolar transistors (IGBTs). Switching events may occur at a rate of over 12,000 Hz. The generated voltage pulses induce an AC voltage onto the motor shaft via parasitic capacitive coupling between the rotor shaft and the stator windings. This may even occur in a properly grounded and suitably electrically shielded motor. Due to the IGBT’s fast rise time of only 50 ns or less, this capacitive coupling may cause the peak motor shaft voltage to reach as high as 60 volts, or higher in some cases (especially for higher AC voltage rated induction motors), unless a discharge path exists. Typically, when the voltage reaches 20- 30 volts or more, the oil film in the bearing breaks down and a discharge takes place. These discharge events occur continuously while the motor is operating, causing the electrical bearing damage to increase over time. This process is also known as electrical discharge machining (EDM) effect. This extremely fast bearing discharge, measured at around 40 ns, instantaneously heats and melts the surface of the bearing race and causes a small pit at the discharge point. Until now, the only ways of detecting this damage have been to remove a suspect bearing and examine it (often after a motor has failed), or to use an oscilloscope – a process that requires expertise, as well as time-consuming wiring and attachment of sensors to the motor. In contrast, DC motors do not suffer from similar bearing problems because: a) The rate of power switching of a thyristor converter is much lower than the IGBT inverter, both in terms of switching frequency (300Hz versus typically 10KHz) and also turn-on / turn-off speed, in other words the “commutation” process takes microseconds rather than nanoseconds to complete and, as a result, the induced voltages are much less. b) The armature of a DC motor has substantial inductance (typically a few tens of milliHenries) which tends to smooth-out any dv/dt transients occurring on the AC supply side. In summary, DC thyristor drives are free of this problem suffered by AC variable frequency drives. DC drives have all the advantages of a fast controlled response over the full forward/reverse speed range for motoring, braking and regeneration, without degrading your bearings. Subscribe for news updates by email // Digg this http://www.sprint-electric.com/news.php?view=20 admin@sprint-electric.com Tue, 17 Mar 2009 15:41:22 GMT http://www.sprint-electric.com/products.php?pid=28 admin@sprint-electric.com Tue, 2 Sep 2008 11:34:41 GMT The Buffer card is a compact interface product for signal processing and amplification. The card has five independent channels with a large variety of uses. E.g. multi setpoint systems, closed loop control, signal buffering etc. http://www.sprint-electric.com/products.php?pid=25 admin@sprint-electric.com Tue, 20 Jan 2009 09:24:05 GMT Easy to use, easy to legend and easy to calibrate with multi-turn scaling and offset presets. A 14mm red LED display makes reading easier. You can calibrate the DPM for your process in the engineering units to suit your signal. A slide in legend saves you time, and money on engraving. Simply slide in your own label. With a standard DIN 43700 case and plug-in screw terminals, you can quickly install these robust, compact digital panel meters. http://www.sprint-electric.com/products.php?pid=23 admin@sprint-electric.com Tue, 20 Jan 2009 09:26:25 GMT Designed primarily for systems integrators and panel builders, the PLA allows you to enhance and simplify any analogue or digital drive control system. It can reduce or eliminate the need for costly PLC or PC based systems. You can use the PLA to work with a range of industrial applications. Easy to use configurable software blocks offer you a powerful and flexible method of processing analogue and digital signals. A 4 button keypad and a large alpha-numeric display make it easier to quickly navigate through an extensive range of software functions. And the included windows based configuration and monitoring software, PL Pilot makes overcoming even the most difficult of motion task quick and simple. To make it easier for you to integrate the PLA into your control system, the drives are fully isolated and have a small footprint. The PLA have a number of fieldbus communications options, including: Profibus, DeviceNet, CC-Link, EtherNet/IP, and CANopen. The PLA is also compatible with drive.web. The drive.web distributed control technology uses Ethernet and powerful graphical tools to provide robust, Programmable Peer Control (PPC) for drives and systems. The drive.web technology is infinitely scalable and cost effective for systems of any size of complexity. For typical motor control systems, it beats using any PLC on cost, performance and easy of use. http://www.sprint-electric.com/products.php?pid=21 admin@sprint-electric.com Tue, 20 Jan 2009 09:28:19 GMT A range of enclosed DC motor controllers up to 12 Amps. Both single direction and reversing options available. The IP20 sturdy metal enclosure, on/off switch and set speed potentiometer make the enclosed drives quick to install and easy to use. The enclosures contain, depending on your power requirements, model 370, 400, 800 or 1200. http://www.sprint-electric.com/products.php?pid=29 admin@sprint-electric.com Tue, 20 Jan 2009 09:28:58 GMT Simple, reliable and compact. Make controlling DC motors easier with adjustable parameters including: minimum and maximum motor speed, armature current, up ramp and IR compensation. http://www.sprint-electric.com/products.php?pid=11 admin@sprint-electric.com Tue, 20 Jan 2009 09:36:24 GMT Three compact models designed to save you time and cost when upgrading your DC motor control system. Switch selection of key drive functions make the 400, 800 and 1200 quick to install and easy to use. You can accurately control your DC motor in one direction of rotation with these 1 Quadrant controllers. http://www.sprint-electric.com/products.php?pid=14 admin@sprint-electric.com Tue, 20 Jan 2009 09:37:01 GMT Fully isolated, allowing you to easily upgrade an existing DC motor control application. The model 400i is a compact and reliable way to control permanent magnet or shunt wound DC motors in one direction of rotation. http://www.sprint-electric.com/products.php?pid=12 admin@sprint-electric.com Tue, 20 Jan 2009 09:37:38 GMT The PLXD is used for controlling external 3 phase thyristor stacks for DC motors, and possesses all the functionality of the PL/X range. It is in the same package as the PL/X 5 - 50 models. The PLXD provides gate drive pulses for driving user supplied pulse transformers with primary pulse current up to 1.5 Amp. There are terminals to accept an externally generated isolated armature current signal, field signal, thermal heatsink sensor switch, and high voltage armature voltage feedback. The unit also provides a +24v supply for the gate drive pulse transformers that is short circuit protected. The following stack configurations can be driven by the PLXD: 1) 6 pulse 2 Quadrant bridge (6 thyristors), or 2 bridges in parallel (12 thyristors). 2) 6 pulse 4 Quadrant regen anti-parallel bridge (12 thyristors). Extra stacks can be used in parallel within the gate drive capability. All customer control terminals are the plug-in screw terminal variety. The PLXD can be used with up to 690v AC on its 3 phase auxiliary supply inputs (EL1/2/3). The external stacks can be of higher voltages if required. The armature voltage inputs can monitor up to +/-1000 Volts DC. There is an integral motor field bridge with independent single phase AC supply inputs (EF2/3) for controlling fields up to 32 Amps. The internal field bridge supply input voltage rating is 480v AC. Provision is made for providing an external field feedback signal and controlling an external field with user supplied primary gate pulse transformer drivers. There is a pulse transformer unit (Product code LA102800) available at extra cost for users who prefer not to supply their own components. It contains all the external interface components required to combine the PLXD with the thyristor stack and its associated Accts (AC current transformers). It includes 12 pulse transformer networks for 2 or 4 quadrant bridges, an armature burden rectifier network, and 2 pulse transformer networks for an external field bridge. The unit is designed to be mounted on a DIN rail and all the interface connections are via screw terminals. http://www.sprint-electric.com/products.php?pid=33 admin@sprint-electric.com Tue, 20 Jan 2009 09:39:25 GMT By interlocking with the drive zero speed signal, you can perform armature reversal using changeover relays. The Rev Unit includes all the necessary logic and relays for reversing and dynamic braking. The Rev Unit is designed to be used with 400, 800 and 1200 single phase DC motor controllers, and is also available with these controllers in an enclosure. http://www.sprint-electric.com/products.php?pid=24 admin@sprint-electric.com Tue, 20 Jan 2009 09:42:21 GMT Sprint Electric Ltd., manufacturer of industrial motor controllers based near Arundel in West Sussex, has been granted a Queen's Award. The Queen’s Awards for Enterprise are the United Kingdom's most prestigious awards for business performance. Sprint Electric has been granted the award in the category of International Trade, recognizing an outstanding and continuous achievement in international trade. The winners are publicly announced on 21 April 2009, the Queen's Birthday. About the award, Sprint Electric’s Managing Director, Edwin Prescott, says, "We are proud to become one of an elite group of companies to have been granted the Queen's Award for Enterprise, the most prestigious business award in the United Kingdom. The award was made to recognize continuous achievement in International Trade. This award puts Sprint Electric among the most successful of UK businesses." Founded in 1987, Sprint Electric designs and manufactures industrial motor controllers, specialising in DC drive technology. DC drives are complex electronic products that can precisely control the speed of automated process machinery. The drives are also able to regenerate excess energy back into the mains supply, an increasingly important feature in this carbon-conscious world. With an export share of approximately 75 percent, Sprint Electric’s products are sold worldwide. Sales Director Gary Keen explains, "Our success owes a great deal to our overseas distributors. We work with some great people, all over the world. Every distributor is offered full training at our offices, so they can support our DC drives in any industrial application. Because we design and build the complete range of products at our Arundel site, we can be very responsive to our customers. Being able to ship our DC drives immediately means our customers receive their orders quickly – regardless of where they are in the world.” Edwin Prescott adds, "This award is a result of our sustained export growth measured over the last six years. We are planning for further growth and are confident of enjoying continued success over the next six years and beyond." Sprint Electric is going to celebrate the announcement of the Award by launching two new more powerful models, which will take the range beyond the Megawatt power level. Edwin Prescott concludes, "Winning the Queen’s Award marks the start of an exciting time for all of us at Sprint Electric and I would like to take this opportunity to thank everyone for their hard work and dedication in achieving this honour." Subscribe for email news // digg this http://www.sprint-electric.com/news.php?view=22 admin@sprint-electric.com Tue, 21 Apr 2009 11:47:55 GMT DC drives manufacturer Sprint Electric celebrates 20th anniversary Sprint Electric Ltd., manufacturer of DC drives in Arundel, West Sussex, celebrates its 20th anniversary this year. The company was founded in 1987 by Edwin Prescott and David Van Der Wee. Sprint Electric offers a wide range of DC motor control, covering a power range from 0.37 to 800KW. Over fifty models are available, analogue or fully digital, covering both single phase and three phase, regenerative and non-regenerative applications, from low voltage servo performance controllers to fully digital three phase DC variable speed drives of many hundreds of amps. DC drives from Sprint Electric are sold all over the world, with an export share of approximately 75 percent. “Our global network of distributors ensures a growing market share abroad where DC drives are extensively used for various industries and where many, originally U.K. based companies, are now producing successfully”, says Gary Keen, Head of Global Sales with Sprint Electric. “However, the domestic market for DC drives is holding up well against a background of decline in U.K. manufacturing. The latest figures for Sprint Electric are promising and our annual turnover has increased by 30 percent compared to last year. This is a combination of both domestic and export sales which highlights the ongoing demand for our DC variable controllers within the U.K. and beyond”, concludes Gary Keen. For the future, diverse applications such as low voltage DC are expected to provide new growth areas and sustain the business expansion in the U.K. Moreover, the replacement market provides good business for DC drive manufacturers like Sprint Electric. Whether in original equipment or in retrofits, Sprint Electric DC drives are being used in many different applications including the metal processing industry, the pulp and paper industry, rubber and plastic processing, lifting equipment, food processing, pharmaceutical and chemical manufacturing. Recent trends are also the leisure industry and ‘non-motor’ applications. http://www.sprint-electric.com/news.php?view=7 admin@sprint-electric.com Tue, 21 Oct 2008 12:04:56 GMT Manual for Buffer card http://www.sprint-electric.com/manuals.php?view=6 admin@sprint-electric.com Tue, 23 Sep 2008 16:05:41 GMT Godiva fire pumps are being used by fire fighters all over the world. The fire pumps for engine and static mounting are manufactured by Hale Products Europe Ltd. in Warwick, England. Hale Products were recently experiencing reliability problems with their three production test rigs. The test rigs were driven by two 250 HP and one 500 HP DC drives and motors. Due to successful volume sales of the Godiva pumps and increasing demand on the production test, it was necessary to upgrade the DC drives. “The test rigs are critical to production output, so minimising the stoppage time between shutting the rigs down and restarting again was the highest priority”, comments Paul Fulford, Production Manager with Hale Products, on the importance of the retrofit project. The local power transmission specialists Andantex Ltd. were chosen to manage the project to replace the drives, and to reinstall and fully commission the test rigs. The refit involved replacing the two 250 HP test rig drives with the latest digital PLX drive modules from Sprint Electric Ltd. The third 500 HP drive would involve reworking the existing thyristor stack and adding the PLXD stack driver from Sprint Electric to upgrade the installation. Start Electrical Services Ltd. provided the specialist knowledge that such an installation requires, along with the re-commissioning of the new drive systems. The whole re-installation of the drives was completed in one week over a bank holiday shutdown. The test rig DC drive and motor takes the place of the normally coupled diesel engine to vary the speed of the pump and test the output flow. Phenomenal flow rates in excess of 6,500 litres of water per minute are normal for the Godiva pump. The test rig also ‘runs in’ the new pump to ensure rotating components and seals are at their optimum performance, thereby ensuring the highest quality when the customer takes delivery. PLX DC drives from Sprint Electric are designed to offer a powerful, flexible and easy to programme digital DC drive. The extensive range of application software functions enable the most difficult tasks to be completed easily and efficiently, making costly external hardware a thing of the past. The 4-quadrant PLX version covers a power range of 5 to 800 kW. The PLX range’s functionality and compact design has proven to be ideal for retrofits when a more cost effective, modern drive system is required. Digg this //  Bookmark this on Delicious // Subscribe to receive newsletter updates http://www.sprint-electric.com/news.php?view=8 admin@sprint-electric.com Tue, 25 Nov 2008 16:03:36 GMT Refurbishing of the Old Stage at The Danish Royal Theatre Keeping DC motors using digital drives from Sprint Electric gives effective and low cost modernization of a historical stage DC drives manufacturer Sprint Electric from Arundel, England, has supplied DC drives for a new stage control system at the historical stage of The Danish Royal Theatre in Copenhagen, Denmark. The beautiful ‘Gamle Scen’, the old stage of The Danish Royal Theatre has been located at Kongens Nytorv in the heart of Copenhagen since 1748 when the theatre was established with royal patronage. Last summer, the old stage’s machinery was upgraded and a new control system was installed by Visual Act, an award-winning Swedish company specialized in stage design and technology. One of the advantages of Visual Act's offer was their ability to extend the lives of the existing DC motors by supplying modern intelligent drives from Sprint Electric. Utilizing nearly all of the original motors and maintaining most of the original mechanics, the much needed upgrade could be carried out at a far reduced cost. In addition to the new control electronics for 36 fly bar hoists driven by DC motors, the scope of work included the installation of a stage control system with four portable control desks and redundant servers; upgrading six lighting bridges for increased lifting capacity; installation of four new manually moveable point hoists, and a complete upgrade of the old revolving stage driven by DC motors. “The refurbishing process at The Danish Royal Theatre in Copenhagen was in many ways special and in some ways unique,” says Visual Act’s design engineer Niklas Philipson. “We could build on the experience gained in upgrading the flying system at the Norwegian Theatre in Oslo.” At this project, carried out in only six weeks during the summer holidays, digital DC drives from Sprint Electric were also used and helped save eight tonnes of cable. “Often the old DC motors are exchanged for AC motors, but we have good experience in keeping them. It is a cost efficient way, as the DC motor drives have very good capacity and durability,” explains Niklas Philipson. For the Danish Royal Theatre’s old stage, new drives and electronics were installed for control of the DC motors on the 36 fly bar winches. To monitor the position of the fly bars, a new arrangement with an angular gear, absolute encoder and limit switch was mounted on each winch. Two Profibus communication channels were provided, one for drives and one for absolute encoders and safety i/o. Sprint Electric’s PLX’s on-board software blocks were used extensively to facilitate the complex system and even a closed postioning loop was incorporated especially for Visual Act. The six existing lighting bridges were upgraded to increase the load capacity to 800 kg. This involved replacing motors, gearboxes and brakes. New electrical cabinets with servo amplifiers and electronics were also installed. In order to increase safety, slack wire detection was added. Angular gear arrangements similar to those used on the fly bars were installed for the light bridge encoders also. The revolving stage was inspected and fitted with new encoders and a very old motor was removed in order to increase the degree of efficiency and reduce risk of fire. The delivery also included four completely new movable point hoists; the point hoists have individual control cabinets that are electrically similar to the light bridge control cabinets and are also connected to the control system through Profibus. The Visual Act Control System is being installed in more and more theatres throughout Scandinavia and is becoming the new standard in theatrical motion control. The system comes with two types of control desks. The Visual Act Advanced Desk includes a full keyboard and is ergonomically designed for work over longer periods. The second type, Visual Act Touring Desk, uses a touch screen and is more compact and suitable for operation from a variety of locations. At the Danish Royal Theatre two touring desks are rail mounted on one of the galleries. The control system operates all movements in the theatre through a combined Profibus and Ethernet network. The networks allow for communication to all devices in the system. The Ethernet is based on the concept of a double redundant ring. A number of hot swap boxes, for control desks, are placed at various points in the stage area. A double emergency stop circuit is connected in series through all the e-stop switches in the system and will cause the system to stop all motion if activated. Sprint Electric’s PLX 4 Q regenerative drives used for the fly bar hoists and the revolving stage are sized between 5kw (12 Amps) and 30kw (72 Amps). They are all fitted with a Profibus communications module and due to the compact size of the PLX, the cabinet size could be kept to a minimum to ease the installation of the complete retrofit system. PLX DC drives from Sprint Electric are being used in many other applications where DC drives continue to provide significant advantages over their AC counterparts. PLX drives are designed to offer a powerful, flexible and easy to programme digital DC drive. The drives’ extensive range of application software functions enable difficult tasks to be completed easily and efficiently without costly external hardware. The PLX is part of an integrated range of 2 and 4 quadrant DC drives. The range’s functionality and compact design has proven to be ideal for retrofits when a more cost effective, modern drive system is required. Digg this //  Bookmark this on Delicious // Subscribe to receive newsletter updates http://www.sprint-electric.com/news.php?view=4 admin@sprint-electric.com Tue, 25 Nov 2008 16:10:17 GMT Sprint Electric offers four quadrant DC drives that use little space and are very energy efficient. Sprint Electric’s 340XRi, 680XRi and 1220XRi DC drives are designed to regenerate energy back into the mains supply under braking without the need for complex intermediate storage, resistive dumping or additional power bridges. This is an important feature in these days of greater attention to energy conservation. Four quadrant regenerative DC drives offer an extremely energy efficient system using their ability to return the braking energy to the mains thereby lowering demand from the incoming AC supply. If these drives are operated on equal driving / braking cycles, the cost of running the drive is only the electrical losses in the motor and drive. By comparison, an AC drive generally uses a braking resistor to control down ramps dissipating the energy as heat to the atmosphere. Continued use in this mode is extremely wasteful. The ability to control the rate of braking is also lost when using braking resistors. A four quadrant regenerative DC drive is fully controllable in both motoring and braking modes, and conserves the maximum amount of energy. The DC drive package offers other energy efficient improvements. In comparison lower speed motoring losses are not as significant as those in AC motors. The DC drive package has better power conversion efficiency across a wider speed range. At the lower motor speeds, the DC drive package provides better power/torque conversion, typically from 10:1 to in excess of 100:1 speed ranges, eliminating the need to ‘oversize’ the motor to achieve useable low-end torque. A four quadrant DC drive is more energy efficient when dealing with torque at start and near zero speeds. The DC drive develops full rated torque at or near zero speed in exactly the same way as throughout the entire speed range. This is because the torque is generated by the linear interaction of the two magnetic fields of the armature winding and the field winding. The commutator ensures that the axes of these magnetic fields are constantly kept perpendicular to each other, thereby in the optimum torque producing position. The resultant torque is practically a linear function of the two DC armature and field currents. The heat dissipation in the windings at a given torque will be constant at any (including zero) speed, and therefore the cooling arrangements can be dealt with in a standard fashion. The DC motor is usually of an open-frame through-vent construction. This suits the purpose of its applications, and allows advantages to be made in terms of ease of cooling, and therefore compactness i.e. a smaller frame size for a given kW rating. Conversely, the AC motor is normally of totally enclosed fan-cooled construction, which places a further burden on the cooling arrangements. The four quadrant DC drive can also independently set the required current levels in each winding to meet a certain load requirement without the need for complicated algorithms since the interaction between the two is practically zero. In contrast an AC motor needs special cooling arrangements to allow full torque to be developed near zero speed. Due to the fact that there is no need for intermediate energy storage (as per DC link-fed inverter), i.e. no electrolytic capacitor bank and choke, the four quadrant DC drive is also far more compact than the equivalent AC inverter. Sprint Electric’s 340XRi, 680XRi and 1220XRi DC drives offer a solution to four quadrant regenerative drive applications. Using little panel space and mounting on standard DIN rail, these drives are designed for use with motors up to 1.8kW, 2Hp. With four quadrant operation, the torque can be reversed very gently or almost instantly, as required. Although compact in size, the 340XRi, 680XRi and 1220 XRi offer all the system functionality required for four quadrant regenerative drive applications. Digg this //  Bookmark this on Delicious // Subscribe for newsletter updates http://www.sprint-electric.com/news.php?view=6 admin@sprint-electric.com Tue, 25 Nov 2008 16:11:59 GMT Sprint Electric provides new drives for naval propeller testing facility VT Shipbuilding, whose headquarters are in Portsmouth, design and construct naval vessels for the Royal Navy and navies worldwide, as well as smaller craft and equipment for the marine, offshore and aerospace industries. During a recent major refurbishment programme at the VT Shipbuilding propeller testing facility, the cavitation tunnel’s control system was retrofitted with DC drives from Sprint Electric. A major supplier to the Royal Navy and one of the world’s leading exporters of naval vessels and technology, VT Shipbuilding has state-of-the-art facilities in Portsmouth. Naval vessels built by VT range from advanced surface warships including frigates, corvettes, fast attack craft and mine counter measure solutions to offshore patrol vessels and patrol craft. The company has a long history of design, development and testing in the field of ship hydrodynamics. VT uses a cavitation tunnel for tests on naval vessels’ propellers. This facility is based in Portchester near Portsmouth. Cavitation is the process where a void or bubble in a liquid rapidly collapses, producing a shock wave. Cavitation often occurs in propellers and can cause undesired noise, damage to components, vibrations, and a loss of efficiency. Propeller tests and the study of forces on rudders, fins, submerged bodies, hydrofoils and cable fairings are carried out in a cavitation tunnel. VT’s cavitation tunnel, first commissioned in 1956, has since then been involved in extensive performance assessments of propellers for both in-house and consultancy work. During a major refurbishment programme that was recently undertaken at VT’s cavitation tunnel, a new drive system was installed. Design, build and installation of the new control system was completed by Hemco Power and Control Systems Limited of Eastleigh, Hampshire. The specialists for electrical control systems used two 4-quadrant DC drives from Sprint Electric to replace the aging Ward Leonard control system that dated back to the 1970s. Using the original motors, one DC drive, PLX65 / 155Amp, now controls the tunnel drive system which operates a 4-bladed impeller to achieve water velocities up to 8m/s. The second drive, PLX40 / 99Amp, operates the Kempf and Remmers propeller dynamometer, which allows a test propeller to rotate up to 1800rpm whilst acquiring torque and thrust measurements. Integrated with new control and data acquisition software, the new PLX DC drives from Sprint Electric now allow for automated control of tests and experiments, bringing with it time savings as well as improved test accuracy and quality, vital for such demanding and sensitive applications as naval vessels. Increase in accuracy and productivity, and lower energy consumption make DC drives ideal for retrofits when a more effective, modern drive system is required. Whether in retrofits or original equipment, DC Drives from Sprint Electric are being used in many different applications including the metal processing industry, the pulp and paper industry, rubber and plastic processing, lifting equipment, food processing, pharmaceutical and chemical manufacturing. DC drives from Sprint Electric cover a power range from 0.37 to 800KW. Over fifty models are available, analogue or fully digital, covering both single phase and three phase, regenerative and non-regenerative applications, from low voltage servo performance controllers to highly sophisticated fully digital three phase DC variable speed drives of many hundreds of amps. Digg this // Bookmark this on Delicious // Subscribe for newsletter updates http://www.sprint-electric.com/news.php?view=11 admin@sprint-electric.com Tue, 25 Nov 2008 16:13:55 GMT Manual for PLX size 4 and 5. http://www.sprint-electric.com/manuals.php?view=31 admin@sprint-electric.com Tue, 9 Jun 2009 14:25:38 GMT DC drives manufacturer Sprint Electric has supplied DC drives for retrofitting the control system of a theme’s park rollercoaster. Chessington World of Adventures, a popular theme park and zoo in south-west London, offers 25 different rides and attractions. One of the most famous attractions is the Vampire ride. It became the UK’s first suspended rollercoaster when it opened in 1990 and the only coaster to fly above tree height. During the summer season, the Vampire now thrills adrenalin junkies of all ages – it is one of the few rollercoasters Europe-wide available also for small children, starting at a height of 1.1m. At peak periods, the Vampire ride attracts 17,000 visitors a day. Three trains make, on average, 720 laps of the track over an eight-hour day. This creates a substantial workload for the ride’s DC motor control system. The ageing control system was becoming costly in both maintenance and downtime. Chessington World of Adventures needed to improve the ride’s reliability ahead of the summer’s peak-season. Chessington World of Adventures had two options: Redesign the control system to use AC motors and AC drives, or keep the existing DC motor control system and retrofit it with modern DC drives. Redesigning with AC technology would mean a lengthy and costly Health and Safety review. Keeping the already installed and proven DC technology proved both easier and more cost effective. System integrator B & G Controls of Sittingbourne, Kent, was contracted by Chessington World of Adventures due to their knowledge of fairground applications. B & G Controls chose DC drives from Sprint Electric because they had previously worked together on another demanding ride application at Chessington World of Adventures. David Garwood from B & G Controls explains, “Two 430 Ampere PLX digital DC drives were installed to control the Vampire’s flight. Each flight has many twists and high-speed turns, but the two lifts create the serious demand. To raise the three trains and 24 passengers, the drives operate at 90 percent current for the first lift and 100 percent current for the second.” To make the ride’s load-run-disembark process a smooth one for the park’s visitors, the PLX has to interface with an existing SLC-500 series PLC from Allen Bradley. “The PLX DC drives’ software made it possible to re-program inside the drive, some of the signals coming out of the PLC to suit the application better. Signals such as Field o.k. and Tacho o.k. required logic function and timer function PLX application blocks to re-create what the PLC needed of them,” explains Sprint Electric’s research and development director Aris Potamianos, who helped with the software integration and commissioning. Other PLX safety features ideally suited to this application are the drive’s coast-stop input and the ability to revert automatically from tachogenerator speed feedback to armature voltage feedback. The PLX's coast-stop input ensures the ride control can effect an almost instant isolation of the drive from the rest of the process in the unlikely scenario of hardware or software failure inside the PLX. The coast-stop input forces the drive to cease supplying armature current to the motor irrespective of drive operating conditions.   Another useful safety feature is the PLX’s ability to automatically revert from tachogenerator speed feedback to armature voltage feedback in case of mechanical or electrical damage to the tachogenerator or its connection medium to the drive. The drive will give a warning of this failure to the PLC but it will continue to be under closed loop speed control until the next convenient stop instance when the fault can be attended to. With the installation and commissioning complete, Chessington World of Adventures’ engineers are pleased with the re-vamped control system, having noticed the ramp up to full speed is a lot smoother now. David Garwood concludes, “The test runs during the park’s closed season were really successful. We were all looking forward to seeing the improvements when the park opened again in the summer.” Excited young visitors’ comments on the Chessington website give evidence that the refurbishment of the Vampire ride was a success: “One of the best rides ever! Great for all ages; my cousins aged five and seven loved it,” says a girl. “This is probably the most exhilarating ride in the whole park – amazing,” comments a boy. And another visitor adds, “Can’t wait to go on it again next year!” Increase in accuracy and productivity as well as lower energy consumption make DC drives from Sprint Electric ideal for retrofits when a more effective, modern drive system is required. Sprint Electric offers a full range of PLX digital DC drives from 12 Amps up to 2250 Amps, with all models available from stock. Whether in retrofits or original equipment, DC Drives from Sprint Electric are being used in many different applications including metal processing, the pulp and paper industry, rubber and plastic processing, lifting equipment, food processing, leisure industries and many more. http://www.sprint-electric.com/news.php?view=25 admin@sprint-electric.com Wed, 10 Feb 2010 12:15:44 GMT Renolit Cramlington Ltd. in Cramlington, Northumberland, produces a range of decorative surfacing materials. The laminates are applied to domestic furniture such as speaker cabinets and kitchen cupboards. Many of these PVC-based laminates are embossed with a wood-grain finish and the embossing line is an important part of the production process. Recently, Renolit Cramlington’s existing embossing line’s control system was becoming obsolete and difficult to maintain, which meant downtime was becoming a problem. After an engineering survey, Oracle Drive Systems, a variable speed drive specialist based in Batley, West Yorkshire, presented two ways to upgrade the drives and the control system: One using AC drives and motors and another using DC drives sourced from Sprint Electric - nineteen 10KW and two 20KW digital PL/X DC drives. “The DC solution offered the best value for money. And because of Sprint Electric’s small drive footprint, the drives were retrofitted into the existing control panel”, explains John Mullins, Oracle Drive Systems’ Technical Director. The retrofit took place within a shutdown period of two weeks, replacing single-phase DC drives, a Leonard and Bauer digital phase locking unit and a Dingden unit, which was a large rack of analogue and digital control cards used to control the line drive system. Bardac Ethernet cards were fitted to the DC drives and a Bardac Smarty, which also sat on the Ethernet network, a DIN rail mounted processor unit, was used to control the phase locking. The functionality of the Dingden unit was replaced by utilising the software within the Ethernet cards and the built-in software blocks of the DC drives. The whole retrofit and re-commissioning of 21 DC drives and the control system refurbishment was completed in two weeks, with Oracle Drive Systems working with shift engineers from Renolit Cramlington. The wireless network allowed commissioning to be done quickly and easily because it was possible to check in/out signals directly using a laptop computer. And because Renolit Cramlington’s shift engineers were involved in the commissioning process, they could get hands-on experience with the new equipment from the start. John Mullins concludes, “Renolit Cramlington’s new digital emboss line has much improved repeatability, is less prone to variation and is much easier to maintain.” Increase in accuracy and productivity, and lower energy consumption make DC drives ideal for retrofits when a more effective, modern drive system is required. Sprint Electric offers a full range of PLX digital DC drives from 12 Amps up to 1850 Amps, with all models available from stock. Whether in retrofits or original equipment, DC Drives from Sprint Electric are being used in many different applications including metal processing, the pulp and paper industry, rubber and plastic processing, lifting equipment, food processing, leisure industries and many more. Subscribe for news updates by email // Digg this http://www.sprint-electric.com/news.php?view=21 admin@sprint-electric.com Wed, 15 Apr 2009 14:55:55 GMT Line Reactor LR48. http://www.sprint-electric.com/manuals.php?view=24 admin@sprint-electric.com Wed, 15 Oct 2008 14:28:22 GMT Line Reactor LR270 http://www.sprint-electric.com/manuals.php?view=26 admin@sprint-electric.com Wed, 15 Oct 2008 14:31:29 GMT Line Reactor LR120 http://www.sprint-electric.com/manuals.php?view=25 admin@sprint-electric.com Wed, 15 Oct 2008 14:31:43 GMT Line Reactor LR330 http://www.sprint-electric.com/manuals.php?view=27 admin@sprint-electric.com Wed, 15 Oct 2008 14:32:25 GMT Line Reactor LR430 http://www.sprint-electric.com/manuals.php?view=28 admin@sprint-electric.com Wed, 15 Oct 2008 14:33:09 GMT Line Reactor LR530 http://www.sprint-electric.com/manuals.php?view=29 admin@sprint-electric.com Wed, 15 Oct 2008 14:34:05 GMT Line Reactor LR630 http://www.sprint-electric.com/manuals.php?view=30 admin@sprint-electric.com Wed, 15 Oct 2008 14:34:56 GMT PLA applications module from Sprint Electric -- Digital drive can reduce need for PLC or PC based systems Arundel, March/April 2008. Sprint Electric offers a Programmable Logic Arithmetic unit (PLA) with extended functionalities for diverse applications and motion tasks. The PLA is a stand-alone applications module that can compliment and enhance any analogue or digital drives system, simplify system design and reduce or eliminate the need for PLC or PC based systems. Designed primarily for use by system integrators, the PLA offers a powerful and flexible method of processing analogue and digital signals via easy to use configurable software blocks. Via its range of configurable inputs and outputs to the internal application blocks, the PLA enables the user to define a control strategy to exactly meet the demands of the process or application. The block diagram created is flexible and has a unique "Configuration Checker" detecting shorts within the user-defined connections. The standard application blocks in the PLA include diameter calculator, taper tension calculator, torque compensation for inertia and friction, motorised pot simulator with power loss memory, two high performance PIDs with gain profiling, two summers with inverting scaling clamping and hysterisis, two filters with precision time constants from milliseconds to 30 seconds, delay timer with roll-over facility, linear or 'S' ramp with independent up-down rates for forward and reverse, four comparators with programmable hysterisis and aperture option, eight multifunction blocks, and many more. All the facilities can be programmed and interconnected with each other and/or the extensive input/output facilities in the PLA. All source and target parameters are described in English or selectable other languages. Additional input/output facilities can be programmed and monitored in engineering units using the diagnostic facilities available within the PLA. The PLA measures 289 x 216 x 110 mm. The module includes Sprint Electrics PL Pilot configuration and monitoring software complete with PC to PLA programming lead. As a Windows based package, the software requires no previous knowledge of any programming language. An RS232 port enables the PLA to communicate to remote equipment such as other PLAs, drives, operator interfaces and other devices. Further connectivity can be achieved for the more demanding applications by the addition of further field bus communication cards including Profibus and DeviceNet. http://www.sprint-electric.com/press_releases.php?pid=21&pr=3 admin@sprint-electric.com Wed, 27 Aug 2008 14:36:30 GMT