IEC 61000-6-4 EMC Testing for 3 Phase Induction Motors?

[BigMotorGuy]

Do 3 phase squirrel cage induction motors (550Hp, 3.3kv, 50Hz) produce EMI which may be problematic for IEC 61000-6-4? Do different neutral grounding systems (i.e. ungrounded, grounded, resistance grounded, etc.) have any affect on this? I believe this standard references a frequency range from 0.15MHz - 30MHz and 30MHz - 1000MHz, but it is my understanding that typically only brush type motors can create electrical noise in these high frequency ranges???

 

[Skogsgurra]

I was absolutely of the same opinion until last year. Then I changed my mind.

It is a very little known fact that induction motors can produce EMI. It does so if the supply voltage isn't balanced or if it contains so much harmonics that the rotor's capacitively coupled voltage gets high enough to cause EDM. The EDM then sends out high-frequency components that, in fact, has disturbed radio communication in an air field near Grenoble, France.
Frame 39 (and 40) in

http://www.gke.org/presentationer/files/GE Bearings and their electric environment w O and E.pdf

explains what happens.

I do not think that any standards organization or any authority is aware of this. So, I do not think that there is any formal need to test an induction motor for EMC. But there may be a practical need to do the test on an installed motor.

Gunnar Englund

http://www.gke.org

--------------------------------------
Half full - Half empty? I don't mind. It's what in it that counts.