Motors and Drives

Advanced Energy adds motor reliability testing

For many years Advanced Energy’s motor team has offered testing consulting, training, and research to end users, utilities, government, original equipment manufacturers (OEMs) and motor manufacturers. Operating the first in the world and still the only independent NVLAP accredited motor test lab in North America has afforded us many opportunities to test motor efficiency. We also have always offered performance testing such as vibration, speed torque curves and customer specified testing that helps determine some measure of a motor’s reliability.

Recently we furthered our motor reliability testing capabilities on a project with an OEM that manufacturers a wide array of products and control systems. The company needed to evaluate motor performance to select the best motor for their application. They have a world-class testing lab with strong capabilities but were not equipped to test motors. That is when they began consulting with Advanced Energy for guidance.

A global RFP was sent out with several motor manufacturers responding. Through performance testing (speed/torque curves) and the OEMs set objectives the candidates were quickly whittled down to two brands. Now the task at hand was to determine, through testing, which motor would hold up best to the operating parameters it would face. Testing the motors over their life span in the field was not feasible or practical. Devising a test in the lab that could simulate the operating life could easily be done but might take years, again not practical.

The OEM’s engineering team was determined to make the best choice and do it within the project timeframe (about three months). Through discussions with Advanced Energy’s motor systems engineers it was determined that the capacitor start motors, that were being considered for this application, weakest links would be the start windings and the switch that automatically engages the run winding once the motor came up to speed. Also, during a normal operating life it was determined by the OEM that their product systems would be operated (turned on and off) 300,000 times. The last thing to determine was how many motors to test to get a fair representation from each supplier.

With five motors from each supplier (10 total) in hand the Advanced Energy team went to work building a test rig and devising a control mechanism to test for motor reliability. There were many issues to be addresses to get 300,000 start/stop cycles within an acceptable time frame. The motors needed to be loaded, they needed to come up to speed to engage the capacitor switch and stop again so they could be restarted quickly, a system for control and remote monitoring needed to be established as testing was continuous seven days a week, and temperature rise from rapid starting and stopping needed to be monitored and minimized as a variable due to the accelerated life cycle testing each motor was being subjected to.

After 10 weeks of testing the OEM now has the information needed to make an informed decision. They have gone to the winning supplier and specified the exact design they will need. And to be safe they are bringing back more of these motors for further reliability testing. When we asked the engineering team at the OEM what this testing has meant to them they said, “Advanced Energy’s flexibility and willingness to make things happen has provided us with a wealth of knowledge we could not have gotten anywhere else. We now have the confidence we need to make a good decision and continue to provide the highest quality to our customers.”