Changes in both hardware and software altered the landscape for drives and motors, says Robert Muehlfellner, director, automation technology, at B&R Industrial Automation (www.br-automation.com). "On the hardware side, a new generation of so-called 'trench IGBTs' for servo drives reduce power loss and lead to smaller drives, and new winding technologies reduce servo motor manufacturing cost," he explains. "On the software side, having a generic and PLCopen standard-based programming interface independent of drive hardware allows the selection of the best drive technology suited for any axis—servo, stepper, induction, brushed DC, hydraulic—without any effects on the application software to control those various types of drives."
For motor or gearmotor improvements, John Morehead, vice president, marketing and strategic planning at Bison Gear (www.bisongear.com), points to efficiency, intelligence and reliability. "We're on the verge of additional legislation for energy-efficiency levels that will cause machine designers to revisit whether they're using the most efficient solution," he says. "Motors today also are more capable of directly integrating with machine intelligence, and some more advanced motor solutions have intelligence built-in."
Kitt Butler, director of the motors and drives division at Advanced Energy (www.advancedenergy.com), submits that 70-90% of all electricity used in manufacturing is supplied directly to motors, which by themselves are the largest single category of electricity end use. "Although the U.S. government is raising minimum efficiency requirements for certain classes of new motors, many of these new motors already require or will soon be in need of repair—an event that is not being discussed by the DOE, even though its 1998 study, the 'U.S. Industrial Electric Motor Systems Market Opportunities Assessment,' concluded that improperly conducted motor repairs have the potential to reduce a motor's efficiency by 1-2%," says Butler.
"Some people are looking into open-loop permanent magnet technology to replace the induction motor," explains Rich Mintz, product management group at SEW-Eurodrive (www.sew-eurodrive.com). "They're expensive, but that's the next level of efficiency. I think we are near the end of efficiency gains in induction motors, and everyone has one of these permanent-magnet designs on the drawing board." Integrated intelligence has impacted drives, adds Mintz. "Most of the higher-end drives have had this for quite a while, but now it is really going to new levels with the ability to communicate directly with PLC or other master network systems and can control multiple axes simultaneously," he says.
Multiprotocol Ethernet architectures create new opportunities with drives and motors, says Dan Throne, sales and marketing manager at Bosch Rexroth (www.boschrexroth-us.com). "By incorporating command, I/O and safety technology, further cost reductions allow further encroachment into other technology areas such as stepper technology by servos," he says.
"Innovative design changes in winding technology have created very efficient and powerful motors in small packages," says John Walker, vice president of sales and marketing at Exlar (www.exlar.com).
Transistor efficiency has increased significantly, and drives are being built into motors even better, says Robert Bigler, CEO of Animatics (www.animatics.com). "Floating-point DSPs are available now at fixed-point prices," he says. "Drives will soon be smarter than ever, and PLCs will become more and more optional."
The areas of improvement that would prompt a new look at variable-frequency drives (VFDs) are integrated network communications, RoHS compliance, smaller physical size, universal motor control, higher performance and embedded PLC functionality, explains Mike Massie, director, drives product marketing, at Yaskawa (www.yaskawa.com).
"While linear motors are not going to replace every belt, precision ballscrew or rack and pinion on the market, they have begun to replace those components in certain automation applications," explains Steve Feketa, global product manager, linear motors and stages, at Rockwell Automation (www.rockwellautomation.com).
"For servos, there are more sophisticated and accurate auto-tune capabilities," says Max Wietharn, vice president, sales and marketing North America for Intelligent Motion Systems (www.imshome.com). "For steppers more advanced control technology prevents loss of synchronization without PID control."
Drives now can calculate energy savings in real time, says Mark Kenyon, product manager, ABB Low Voltage Drives (www.abb.com). "Never has the case for energy efficiency been more compelling," he says.
"There has been a step change in the usability of drive systems brought on by plug-and-play configuration between drive and motor," adds Craig Nelson, product marketing manager, Sinamics S servo and vector drives, at Siemens Energy & Automation (www.sea.siemens.com).
|High Starting Torque Drive|
3G3RX ac drives with open- and closed-loop vector have high starting torque of 200% at 0.3 Hz for zero-speed load holding. Combine an encoder with 3G3RX drives for feedback to perform low-precision positioning applications. A filter lowers noise impact on other drives and equipment.