Effect of higher frequencies on breaker and CT

[pukar12345]

Hi All,

I have a feeder feed by Variable Frequency Drive (VFD)of 60-200HZ.
I have breaker and CT after VFD. Is there any effect on CT and breaker when frequency changes from 60 to 200hZ.

 

[davidbeach]

Don't do that. Just rely on the protections of the VFD. Most relays won't work above 75Hz, if even that high. The VFD will do a perfectly goo job. Breaker after the VFD is just asking to fry the VFD.

 

[scottf]

CT performance improves with frequency up to a certain point. Normally that's around the 30th harmonic or so.