Protections for standby set

[dcset]

HI,
I have ask for a cabinet to control on start, stop, alarms of a standby set, 3000 kva, according to nema standards, friday, i cheek the wirings and saw there´s no alarms on pt100´s of the winding of generator, for me here in Europe, the normal situation in this size of genset is to have this protection for the temperature of winding generators.
Please, could somebody tell me according to nema what the standard talks about this protections, or the minimun requirements for a standby group more than 3500 kva, please tell me references or some place where i could read and show this guys about the need to install this protection, cause i think they will discuss with me that it´s no needed.
thanks a lot

 

[7anoter4]

I don't know if NEMA requires RTD monitoring of slot temperature but usually NEMA motors and generators on frame 360 and larger are provided with RTD. The National Electrical Manufacturers Association (NEMA) recognizes embedded detectors as a standard protection for motor and generator insulation.
Usually all the motors and generators of medium voltage I saw were provided with 6 RTD [pt100] and 2 pt100 for bearings. There are 3 terminal boxes: for main power, for stator RTD's and for bearing.
If the Generator is for emergency purpose one may avoid this protection to trip the power whatever as the supplied equipment has to stay energized in any case.

 

[dpc]

There are no code requirements for use of stator RTDs on a generator. It would probably be fairly common for a base loaded 3000 kVA generator, but pretty uncommon for a standby generator.

If these are not specified when the generator is ordered, I would not expect to see them.

David Castor

http://www.cvoes.com

 

[dcset]

Thanks a lot for your time,