Control Engineering Motors, Drives, & Motion Control eNews for December 2002



National Instruments -

Motion Assistant Makes It Easy
National Instruments Motion Assistant is a revolutionary new development and code-generation tool for motion control system programming. It offers an intuitive point-and-click interface where you develop your motion control applications and then generate the LabVIEW code, thus helping you make motion control easy.


National Instruments
Tel: (800) 452-6914 (U.S. and Canada)
Fax: (512) 683-9300
URL: Click Here

Let's go forward with more confidence in ourselves and our objectives
as we bring this tough, tumultuous year to an end.

- Frank Bartos, Executive Editor, Control Engineering



Unidrive goes more ''universal''

New Unidrive SP (Solution Platform)

Building on its pioneering development of Unidrive in 1995 that offered several methods of ac motor control in one unit, selectable by software, Control Techniques (Eden Prairie, MN; Newtown, Wales, U.K.) has just introduced a new generation ''universal'' ac drive named Unidrive SP (Solution Platform).

Through the universal drive selection feature, Unidrive SP can operate in the following control modes: V/Hz, open- and closed-loop vector, brushless servo, and regeneration. The single drive approach offers potential savings in equipment cost, inventory, training, and maintenance. Universal encoder feedback permits software selection of up to 14 feedback signal types-including absolute encoders-as a standard feature. A series of optional plug-in solution modules (SMs) further enhances Unidrive with control, communications, interface, and connectivity functions. As many as three SMs can plug into the drive at one time. SMs are available for extended PLC functions; servo control mode; resolver feedback; a duplicate universal encoder, also usable as simulation output for any of the encoder signal formats; five fieldbus communication options; and extended I/O feature.

Initial Unidrive SP sizes are in the 1-40 hp size range, in normal- and heavy-duty versions. The servo mode provides 1-484 lb-in. continuous torque. Models are available with 208-575 V ac inputs. The product line will be expanded to 1,300 hp and inputs to 690 V.

Another standard feature is Smartcard, which gives operators ability to program a vast number of control parameters to ease drive setup, programming, and maintenance. Smartcard also stores parameters for automatic backup and economical cloning of multiple drives, among other functions. Rounding out Unidrive SP's many features are user interface choices, onboard EMC filter, 24-V dc control supply input (back-up during commissioning or supply disconnected), 48-V dc back-up power supply input, and a secure disable feature that stops drive torque generation during standby or stop mode, without extra parts.

Pricing is equivalent to existing Unidrives, with the added benefit of new technology, says Control Techniques, which is an Emerson Industrial Automation company.

For more information, visit the Emerson web site .

Let me know your thoughts about applying this high-capability ac motor drive in your automation plans: Email me at

Motor rewinding without fear of efficiency loss

Results of a comprehensive study should dispel users' fear about effects of rewinding on energy efficiency of their motors.

Many users have the misconception that rewinding reduces efficiency, leading to confusion when a repair or replace decision must be made. With more than 97% of motor lifetime costs going to electricity usage, the right decision is crucial to operating costs.

Launched in 2000-under the leadership of the Electrical Apparatus Service Association (EASA, St. Louis, MO) and the Association of Electrical and Mechanical Trades (AEMT, Layerthorpe, York, U.K.)-the study concludes that when ''using best repair/rewind practices,'' electric motor efficiency can be maintained within

Key to such positive results is the use of best practices, which the report outlines.

The study was based on testing and analysis of 23 motors in the 50-300 hp range. Motor varieties included low voltage, medium voltage, IEC and NEMA designs, 50 and 60 Hz models, totally enclosed fan-cooled, open drip-proof, and 2- and 4-pole speeds. ''Ten of the world's largest electric motor manufacturers provided motors, technical data, assistance,'' according to EASA. Also sponsoring the project were the U.S. Department of Energy, the U.K.'s Energy Efficient Best Practice Program, and other British agencies.

For more information, including a white paper, ''The Results Are In: Motor Repair's Impact on Efficiency,'' and related publications, visit '' Industry Info ''.

For more information on AEMT , visit the company web site.


Software briefs: AGVs, ActiveX interface

End-users interested in automatic guided vehicle (AGV) systems can obtain free guidance in the form a PC program offered by Siemens Dematic, Rapistan Material Handling Automation Division (Grand Rapids, MI). With Q-CANDesigner program, prospective users can create their AGV design and run a demo of the proposed system on a PC. The trial version of the program includes video tutorials about using the program; sample system demonstrations; photo and video libraries of AGV systems in action; a comprehensive user's manual; printable literature; AGV specifications; real-time video help system; and other planning, layout, and reference tools. Q-CANDesigner doesn't require CAD experience, software knowledge, or direct vendor support.

To request a free trial-version program, click here for a request form.

Intended to speed the development of motion control and machine control applications, Motion Engineering Inc. (MEI, Santa Barbara, CA) recently released an ActiveX-compatible programming interface called MPX. End-users can more quickly program complex, multi-axis motion control with the new interface, while machine builders can create custom, specialized motion applications with VisualBasic, LabView, VBScript, XML, and other languages that support ActiveX controls, according to MEI. MPX programs can be compiled as stand-alone applications, or run directly in their native environments. MPX comes complete with the company's Microsoft Windows utilities MotionConsole and MotionScope, full documentation, and various sample projects.

For more information, visit Motion Engineering Inc .

Accurate, affordable in-cylinder position sensing

Are you looking for a lower cost alternative to non-contact position feedback devices for use in hydraulic and pneumatic actuators?

TDP-100 sensor's wear-resistant hybrid-track technology uses high-resistivity conductive plastic bonded to a precision wire-wound element.

If so, TDP-100 in-cylinder position sensor from Transducers Direct (Cincinnati, OH) may be your solution. The device provides absolute analog output and 0.15% linearity, without extra electronics. TDP-100 is available for a wide range of actuator sizes in travel lengths of 25-200 mm (in 5-mm increments) and 210-1,100 mm (in 10-mm increments). Operating temperature ranges from -30 to 100 °C.

For increased device reliability, the sensor mounts inside rather than outside of pressurized cylinders up to 7,200 psi (500 bar) that work with mineral-oil-based fluid. Testing to more than 50 million cycles at 25-mm stroke length and 250-mm/s speed speaks for the sensor design's durability.

TDP-100 sensor comes in two versions. The internal-flange version suits clevis-style actuators, where the flange can be completely encapsulated within the cylinder bulkhead. For tie-rod-style actuators, the external-flange model has industry-standard threads, with custom sizes available. List price starts at $275.

For more information, visit Transducers Direct .

Charitable season for technology

Donation of a 350-hp ABB DriveIT variable-frequency drive-ACS 600 with proprietary open-loop Direct Torque Control technology-was part of ceremonies to mark ongoing advances at Texas A&M University's Multiphase Field Lab, on December 5, 2002. The donation included drive installation, commissioning, and start-up engineering services with a total value of about $65,000.

ABB's drive will help Texas A&M students research multiphase pumping methods for oil and gas. Variable-frequency drive (VFD) technology enables pumps to be energy efficient and maximize oil/gas retrieval and transmission to processing facilities. The VFD will be used to power and control multiphase pumps at Texas A&M's Riverside Test Facility (near College Station, TX). The drive and pumps represent the latest technology being applied in oil and gas fields. To produce oil, companies have to handle natural gas typically associated with oil deposits. Multiphase pumps allow removal of the oil and gas mixture from the well and transmission through pipelines to processing facilities, where oil-gas separation is less costly, among other benefits.

For more information, visit the ABB web site .

State-of-the-art equipment and learning tools will give students hands-on training at Ranken College's renovated 2,500-square-foot Industrial Electronics Lab.

Also in early December, Siemens Energy & Automation Inc. (SE&A, Alpharetta, GA) announced that it will supply Ranken Technical College (St. Louis, MO) with industrial control products to outfit the institution's Industrial Electricity and Electronics Technology program-as part of an industry/academic partnership between SE&A and Ranken. Industrial motors, motor controls, operator panels, power distribution systems, and automation components make up the new equipment supplied. The donation is valued at $100,000, including product training for Ranken faculty and staff.

For more information, visit Siemens Energy & Automation Inc .

Contemporary Controls (Downers Grove, IL) announced, November 12, 2002, that it has donated a CAN PC/104 module to boost a student robotic project at Sherbrooke University (Quebec, PQ, Canada). The Perius Team of 11 mechanical, electrical, and computer engineering students will compete with 40 other teams in the Walking Machine Challenge to be held in Mexico in April 2003, sponsored by the Society of Automotive Engineers (Warrendale, PA). A six-legged pneumatic robot being designed and built by the team reportedly will be able walk, run, and even jump. The innovative robot design, based on the walking dynamics of insects, will use Contemporary Controls' module to enable bi-directional communication with error management.

To keep track of the robot's progress on the robot, click here .

For more information, visit Contemporary Controls .

Control Engineering in November and December

As usual, in-print help with motors, drives, and motion control appears in each issue of the magazine.

My November article on ''Medium-Voltage Motors'' explores the contribution of electric motors that operate from supply voltages above 600 V to handle larger loads more efficiently than their more common but low-voltage counterparts. Among several advantages, MV motors limit power losses in long supply cables. Click here to read the article .

In the Products and Software section, Siemens Energy & Automation (Alpharetta, GA) introduces the MicroMaster 4 family of drives for 1/6-300 hp ac motors. These fourth-generation inverters are billed as offering more features for less cost.

Visit Siemens Energy & Automation for more.

Parker Hannifin, Compumotor (Rohnert Park, CA) refers to its new ViX intelligent servo drive as a ''dc-powered servo alternative to ac drives.'' The compact unit combines a controller and 250/500-W output stage.

For more, visit Computmotor .

In the December issue's Up Front section, Pack Expo 2002 highlights include Danaher Controls' (Gurnee, IL) Dynapar Acuro single- and multi-turn absolute encoders; and Decentralized Control Technology from SEW-Eurodrive (Lyman, SC) that promotes the advantages of distributed control architectures for motor and machine control.

Visit Danaher Controls and SEW-Eurodrive for more.

In December Products, Binsfeld Engineering's (Maple City, MI) Torque-Trak Revolution series provides monitoring of torque, power, speed, and direction of a shaft by non-contact (wireless) means.

For more, visit Binsfeld Engineering .

Motor innovations: Linear actuator, torque motors

A low-mass innermoving coil contributes to the quick mechanical response time of Servo Magnetics' actuator.

Voice-coil actuators permit direct generation of linear forces, without the complexity and cost of a mechanical rotary-to-linear conversion device, such as a ballscrew or gearbox. The reduction of parts also can improve reliability and life of a motion system.

Servo Magnetics Inc.'s (Canoga Park, CA) new compact voice-coil actuator targets applications that need linear force with high acceleration or high-frequency actuation. Measuring 1.25-in. diameter by 1.375-in. long, the linear actuator produces peak forces greater than 3.5 lb, with approximately 45 W of power. Custom mountings and winding configurations are available.

For more information, visit Servo Magnetics Inc.

Torque motors, such as Etel's TMA family, simplify machine design and reduce cost by eliminating worm-gear drives or other transmission elements.

Three new torque motor models from Etel Inc. (Schaumburg, IL) are specifically engineered for demanding performance requirements of the latest machine tools. TMA-0175, TMA-0291, and TMA-0450 series (corresponding to the motor diameter) fill the moderate to high-torque range of 20 to over 1,000 Nm (14.75-737 lb-ft). These direct drive, brushless, ring torque motors increase machine tool accuracy and velocity stability, provide very high bandwidth, and reduce wear and maintenance. TMA torque motors include liquid cooling provision to eliminate heat transfer to the machine structure. They are compatible with a wide range of popular CNCs and servo controllers.

For more information, visit Etel Inc.

Worth reading: Observers tell about plant behavior

A new book, ''Observers in Control Systems, A Practical Guide'' (Academic Press, ISBN 0-12-237472-X) by George Ellis, senior scientist at Danaher Motion, Kollmorgen (Radford Va.), will be of interest to control engineering professionals in general, as well find a place in the reference library of motion-control specialists.

Observers are algorithms that estimate the behavior of a plant (or element being controlled) from feedback sensor output and the excitation applied to the plant. Using the excitation signal, observers can tell us much more about the plant than the feedback device alone. Observer also can make high gain settings practical to obtain fast settling times, which are important in motion control, for example.

In eight chapters, this book reviews the place of observers in control systems; the frequency domain, which is the most common analytical basis for control systems; and various aspects of the popular Luenberger observer. Five appendices-two of them related to industrial servo systems-add to the book's usefulness. In observer-based resolver conversion, eliminating phase lag between position and velocity feedback is among items discussed. Ways to cure low-frequency servo system mechanical resonance are covered in the other motion-related appendix.

For more information, search by title at the Control Engineering bookstore .

Also visit the Kollmorgen web site for more.

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