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Inside Advanced Energy’s Motor Test Lab | August 2005
A quarterly electronic publication for companies applying electric motors
- Testing Your Product
- Increasing Dynamometer Capabilities
Testing Your Product
Most OEMs understand that to remain competitive in today’s global economy, cost-reduction programs are a necessary way of life. Electric motors are frequently one of the higher cost sub-assemblies in their product offerings; therefore, they tend to be good candidates for savings per unit produced. Cost (purchased price) is only a part of the cost equation. Warrantee cost, the cost to the company’s reputation and potential loss of market share are also at stake should your product not perform. One way to determine that you have chosen a reliable alternate supplier is to perform side-by-side performance and accelerated endurance tests.
Here are highlights from two recent test projects completed by Advanced Energy.
- One client requested that we perform characterization tests on several motors manufactured in China. The motors arrived well-packaged and with no indication that they were mishandled during their transit from the manufacturer. The stator of one of the motors had shifted so significantly that the cooling fan on the rotor rubbed one of the end shields when it was energized. The screws that held the auxiliary conduit box in place on another motor were stripped causing the box to vibrate while operating, resulting in an unacceptable noise level. Another motor exhibited very high stray losses and unusual power factor characteristics. Without precision instrumentation, only the obvious deficiencies of this "vendor qualification batch" could be detected - and there’s no telling what other complications would occur.
- Results of another client’s side-by-side characterization and 200,000 cycles of accelerated endurance testing were very favorable for the alternate motor tested. Changing to this alternate motor will save the client at least $150,000 annually for the life of the design.
Increasing Dynamometer Capabilities
After 14 years of service, Advanced Energy retired its first dynamometer (a Clayton water brake) which helped us gain a national reputation for accuracy and repeatability unmatched by any other independent electric motor test lab world wide. Our Clayton was primarily used for testing motors in the range of 20 to 200 hp up to 8,000 rpm for efficiency.
Our new dynamometer (which employs eddy current technology) was commissioned June 1, 2005 to test motors from 20 to 250 hp up to 9,000 rpm and is already busy at work testing motors for a U.S. Department of Energy (DOE) research project. We currently have dynamometers with the following range of performance:
- Constant torque, high load inertia: 1,200 Nm (800 lb-ft), 0-1,800 rpm, 300 hp maximum.
- Variable torque, low load inertia: 0-8,000 rpm, 1,320 Nm (880 lb-ft), 250 hp maximum (8,000-9,000 rpm @ 125 hp maximum).
- Small motor capability down to 0.25 hp. Lower horsepower available with consultation.
Our lab is the first in the world to be NVLAP accredited under the National Institute of Standards (NIST) for motor efficiency testing program and still remains the only independent motor test lab in North America with this accreditation. We are proud to maintain accurate results with a repeatable of +/- 0.2 percent.
Inside Advanced Energy’s Motor Test Lab brings you the latest information about our strategic plans to enhance our testing capabilities especially in the area of motor reliability. For more information about Advanced Energy’s motor test and consulting capabilities, visit our website at www.advancedenergy.org or contact David Berkowitz at 919 857-9047 or dberkowi@advancedenergy.org.
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