Exploding Surge Packs in Motors
Exploding Surge Packs in Motors
(OP)
I work for a company that has two main air compressors powered by 2 36KW synchronous motors. They are soft started by a medium voltage VFD and placed on an 11KV run bus that has vacuum type contactors. Over the past several years lightning strikes has caused two of the surge packs in the motor T-boxs to explode and damage the motors(analysis from motor factory). We would like to eliminate the surge packs. A friend informed me that there was a test called a "steep front voltage" impluse test that couls be preformed on a sample stator coil. If the coil withstood this impulse then there really was no need to have the surge packs. Yes the surge packs are sized properly with ample margin. Has anyone heard of this test? I would also like some reference soources. Thanks.





RE: Exploding Surge Packs in Motors
=====================================
Eng-tips forums: The best place on the web for engineering discussions.
RE: Exploding Surge Packs in Motors
Why have surge caps on motors fed by VFDs anyway? if there is a line surge it might damage the VFD. But don't forget, the VFD output is akin to being a new power source for the motor circuit, so the only "surges" the motor terminals would see would have to come from the VFD transistors (unlikely) or from a complete catastrophic failure of the VFD, in which case the motor damage would be the least of your worries.
JRaef.com
Eng-Tips: Help for your job, not for your homework Read FAQ731-376
RE: Exploding Surge Packs in Motors
RE: Exploding Surge Packs in Motors
JRaef.com
Eng-Tips: Help for your job, not for your homework Read FAQ731-376