lectronic motor drives have the same problems as almost all the product categories we&rsquove written about lately: A declining market over the past several years, a move of major markets to Asia, and a dearth of new products and technology hitting the street all at once. When a market is down, manufacturers tend to cut back on research, development, and new products, and the same appears to be true with motor drives.
The North American AC and DC drives market declined 2.3% over the past two years, says , mostly because of the Iraq war. It expects a slight pickup in the North American drives market in 2004, but a fall off in 2005 and 2006.
The Asia-Pacific market for AC and DC drives is booming, however. No surprise there. predicts sales of high-power AC drives will grow 11.1% in China over the next five years, while IMS says overall drive sales will grow in India by 13.3%.
ARC says the motion control market in North America is stepping up, and predicts a annual growth rate of 6.2% over the next five years, with machine builders on the front line of development. ARC says manufacturers are faced with the need to handle greater product variations, run at faster production speeds and achieve higher quality. To achieve this, ARC analysts say, machine builders will put advanced motion control techniques into new production equipment.
Trouble is, according to ARC, the motion control industry is engaged in standardization battles involving networks, programming languages and architectures and machine builders are in the thick of it.
Therefore, as machine builders seek new and advanced drives and motion control systems that conform to some—any!—sort of standard, they may be frustrated by the lack of new products available. Several of the products covered in this year&rsquos roundup are largely warmed-over versions of older products, with a few &ldquoenhancements&rdquo thrown in. Similarly, few manufacturers are taking the lead in setting standards. However, as always, there are a few new technical advances hidden amongst the products we&rsquore listing here so read carefully.
This might not be troubling to you, but we&rsquove also noticed that when it comes to motor drives, there seems to be a distinct decrease in the quality of certain vendors&rsquo marketing communications. For example, several of the product descriptions we received were virtually indecipherable. Just when machine builders need to be able to fully understand the complexities of the technology, suppliers appear to be unable to articulate just what makes the re products so special. I guess that&rsquos where we come in.
Perhaps drive and motion control vendors are waiting for something clearly positive to happen so they can unleash all their pent-up new product designs and pay professionals to communicate all the major advances in motor drive technology. We&rsquore ready, and we expect you are too.
Variable-speed AC Drives
Allen-Bradley PowerFlex 700H and 700S AC drives are available in power ratings 0.5-450 hp at 400 and 480 V. Machine builders can integrate drives into a manufacturing process using NetLinx, DeviceNet, ControlNet or EtherNet/IP networks. Software includes DriveExecutive and DriveTools SP for programming, configuration, monitoring and troubleshooting. Options include 24 V or 115 V digital I/O plus analog I/O. All drives are CSA/cUL-certified, UL-listed, and carry the CE mark.
Rockwell Automation: 800/223-5354,x1686; www.ra.rockwell.com
Motion Controller Uses Fire Wire
Automation 3200 NMotion SMC controller offers 32 axes of synchronized motion control through one interface, expandable to 62 axes. It uses a distributed control architecture that enables it to maintain performance independent of the number of axes being controlled. This avoids the processing bottleneck caused by its previous single-processor control architectures. Trajectory generation is done on the PC, which sends incremental position commands to a drive via the IEEE-1394 (FireWire) serial bus.
Aerotech: 412/963-7470; www.aerotech.com
Seven-axis Motion Controller
The NextMove ESB provides seven axes of motion control, including up to three axes of servo and four axes of steppers, or seven precision servos. It supports servo loop closure times of 100 Âµsec and will provide pulse and direction for steppers up to 500 kHz. On-board I/O includes 20 digital inputs, 11 digital outputs, two 12-bit differential analog inputs and a precision 12-bit output.
Baldor Electric: 800/828-4920; www.baldor.com
Amplifier Attached to Motion Controller
The AMP-20540 servo amplifier board attaches directly to the 96-pin DIN connector of the company&rsquos DMC-2143 controller without the need for cable or wiring. The board drives brush and brushless motors up to 500 W. The 6.92x4.85 in. board contains four transconductance PWM amplifiers, each capable of producing up to 500 W. It accepts 18-60 VDC, produces 7 A of continuous current and has a PWM switching frequency of 60 kHz.
Galil Motion Control: 800/377-6329; www.galilmc.com
Smart Servo Drive Goes Camming
Compact Compax3 provides position, speed or torque control, label registration, and advanced gearing. Multiple units can be synchronized for multiaxis applications. Units incorporate motor drive, full-feature controller, and power supply in a single module. Setup is done with an intuitive interface, wizards, online help and an oscilloscope function. Motion controls include advanced camming, curve linkage virtual master, feed-forward, observer, and over-sampling functions.