Control Engineering Motors, Drives, & Motion Control Newsletter for June 2000
In this issue:
Medium-voltage ac drives on the move - ashore and under water
Rejuvenated medium-voltage (MV) ac drives are making some agile moves for such large sized equipment. On May 26, ABB (Turgi, Switzerland) launched its ACS 6000 MV ac drive family, rated from 6 to 27 MW at supply voltages up to 3.3 kV. This extends the range of ABB's MV drives substantially above 5 MW provided by ACS 1000-launched in late 1997. ACS 6000 is being marketed worldwide on an industry-specific basis, with units for the metals sector (rolling mill main drives) now being built, as I saw during this product launch-press event. I was also excited by a demonstration of how ABB is developing a deep submersible version of ACS 1000 medium-voltage drive for variable-speed control of subsea pumps in offshore oil and gas production. More in a later issue of Control Engineering .
Figures verify open-loop usage dominates step motor systems
One of the themes in my June cover story on Step Motor Systems (see below) is the growing, but relatively limited use of position feedback. Market numbers from technology research firm Motion Tech Trends (Inglewood, Calif.) back this up. MTT estimates the North American market size for step motors and drives in factory automation (FA) at $172 million in year 2000. Of these FA sector stepper systems, 92% run in open loop, 5% in closed loop with end of move position verification, and 3% in fully closed loop, says MTT. All values are in terms of dollars.
Need to empower your processing intensive motor controllers? Take a look at a spate of new digital signal processors (DSPs) coming. Availability of the devices is between now and 4Q2000.
Analog Devices (Norwood, Mass.) just introduced ADMC5xx Series DSPs with 1-300 MIPS (million instructions per second) speed for digital control of motors in the appliance, factory (and office) automation markets. DashDSP includes 64-KB flash memory, an integrated 12-bit flash A/D converter, full controller area network (CAN) bus implementation, etc. Why would such 'seemingly simple' applications need high-performance DSPs? It's the motor manufacturers' need for software development, complete system simulation, and debugging capabilities. At the same time, DashDSP will perform complex modeling for sensorless motor control, diagnostics, and predictive maintenance functions, according to Phil Davies, director of ADI's Motor Control Group.
Motorola Inc. 's (Phoenix, Ariz.) newest chip announcement is the DSP5680X line that features DSP architecture with MCU capabilities. Four new 40-MIPS, flash-memory-based DSP controllers offer PWM modules specific to motor control. Interfaces for both synchronous and asynchronous communication are included.
Texas Instruments (Dallas, Tex.) has released its C24X Series DSPs operating at 40 MIPS, specifically for speed control of small industrial, commercial, and appliance motors. Among device features are 16 pulse-width modulated (PWM) channels, a CAN bus module, serial communication/peripheral interfaces, and a 10-bit A/D converter.
New digital dc winder drive
Who says new initiatives are past for dc drives? Reliance Electric WebPak 3000 DC Winder drive, recently introduced by Rockwell Automation (Cleveland, O.), adds numerous functions specific to the needs of users in web handling, such as programmable field shaping over a 6:1 range; gain profiling based on roll diameter; and parallel or cascade outer loops for position, current, and tension. Based on the company's FlexPak 3000 product, the new 3-phase, regenerative adjustable-speed drive comes in 1.5-75 hp ratings (at 230 V ac supply) and 2-150 hp (at 460 V ac).
Unidrive now available at 230 V
Said to be first motor drive to offer five operating modes in one package, Unidrive from Control Techniques Americas/Emerson Motion Control (Eden Prairie, Minn.) now comes in 230 V input models with 1-30 hp output (3-70 A). These drives complement prior 460-V units of 1-1,600 hp range (2.1-2,400 A) and have potential for inventory cost reduction and ease of use benefits. Simply change Unidrive's control mode-among V/Hz, open-loop vector, closed-loop vector, servo, and regenerative control-via the front panel or the company's UniSoft configuration software. The Windows-based tool allows user access to 750 drive parameters.
Control Engineering in June
See my June cover story ' Step Motor Systems Battle for Motion Control Market Share ,' which is an update on how steppers compete and, at the same time, combine with servo systems. DSP-based stepper drives, integrated packages, and an Asia/Pacific snapshot round out technology and user issues. Please take part in our 10-second survey of what you look for in a stepper system.
Other motor/motion-control-related coverage includes company news about the latest moves of Danaher Corp. on Kollmorgen and Colfax Automation 's Warner Electric; also in news is a market highlight on numerical control software. In the products section, see motion control programming software, a sensorless servo controller, and multipurpose servo drives.
Help for the beleaguered designer or user
A six-page reference guide-entitled 'Smart Motion Control Cheat Sheet'-loaded with formulas, conversion factors, reference data, and tutorials to figure out 'every aspect of a motion control system' is available as a free download from AutomationSolutions (Petaluma, Calif.). One question: Why not a more positive name for such a useful technical aid?
Released earlier this year, 'The Allen Bradley Practical Guide to Motor Control' is intended for motor management professionals. Available from the Automation Bookstore , this CD-ROM simplifies the mysteries of electric motors and associated controls, such as relays, starters, sensors, overload protection devices, and pushbuttons.
Long-standing Motion Control Symposium
Both recent advances and existing technologies will be on review at the 29thannual Incremental Motion Control Systems & Devices Symposium to be held July 17-29 at the Radisson Marine Hotel, Berkeley, Calif. An extensive technical program of lectures on motion systems (motors, actuator devices) and controls, four short courses, and a table-top exhibit will be presented. Contact Dr. B.C. Kuo at firstname.lastname@example.org .
A recent book provides practical know-how on the complexities of brush permanent magnet (PM) dc motor design. Yes, I said brush dc-the motor type that 'continues to die' over the decades, yet is used in large numbers in automotive and other cost-sensitive markets. 'Design Handbook for PM Motors & Tachmometers' by Robert C. Perrine, Sr. is available from the publisher, Motorsoft Inc. (Lebanon, O.), contact email@example.com .