Sliver
Member
I have a 800hp 4160V induction motor (FLA 104) that is tripping on current overload and I have a question about the CT sizing.
How can the motor protection unit (GE multilin 469) that uses a 0-5A CT input measure 500Amps when the CTs used are labelled 100:5 Amp. The 469 would have to be able to see 25A? This unit has been in service for many years and the 1,000 HP motor (FLA 127 A) uses 150:5 CTs without problem.
Shouldn't the primary of the CT be greater than the FLA?
thanks,
Brian.
How can the motor protection unit (GE multilin 469) that uses a 0-5A CT input measure 500Amps when the CTs used are labelled 100:5 Amp. The 469 would have to be able to see 25A? This unit has been in service for many years and the 1,000 HP motor (FLA 127 A) uses 150:5 CTs without problem.
Shouldn't the primary of the CT be greater than the FLA?
thanks,
Brian.