Synchronous Motor & Need for Rotor Earth Fault Protection
Synchronous Motor & Need for Rotor Earth Fault Protection
(OP)
Is this required!
What is the practice generally!
I find Shell standard doesn't recommend Rotor earth fault protection for Synch motors (it recommends Loss of excitation protection).
The Steel industry in India specifies in their purchase requistion.
Siemens motor unit says, 90% of Synch motors supplied by them world over are without Rotor earth fault protection.
Look forward to hearing from you.
Thanks.
What is the practice generally!
I find Shell standard doesn't recommend Rotor earth fault protection for Synch motors (it recommends Loss of excitation protection).
The Steel industry in India specifies in their purchase requistion.
Siemens motor unit says, 90% of Synch motors supplied by them world over are without Rotor earth fault protection.
Look forward to hearing from you.
Thanks.






RE: Synchronous Motor & Need for Rotor Earth Fault Protection
i don't know if it's some standard.
What is size of motor and volatges.
function 40( loss of excitation)is must and 55( loss of synchronizm) not bad practic. 64R, we provided on all big synch motors.
Between us, is not so expensive.
best Regards.
Slava
RE: Synchronous Motor & Need for Rotor Earth Fault Protection
It could also be possible to resistively ground the supply transformer feeding the field bridge to limit the fault current.
RE: Synchronous Motor & Need for Rotor Earth Fault Protection
RE: Synchronous Motor & Need for Rotor Earth Fault Protection
This is true!!!
Regards.
Slava
RE: Synchronous Motor & Need for Rotor Earth Fault Protection
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If we learn from our mistakes I'm getting a great education!
RE: Synchronous Motor & Need for Rotor Earth Fault Protection
Scotty UK,
Thanks. I agree with that.
The issue is to do with the Synch motor with the brushless excitation and vendors are not recommending the same saying it is not much of use and affects integrity due to the need to increase the shaft length to accommodate additional slip ring.
RE: Synchronous Motor & Need for Rotor Earth Fault Protection
----------------------------------
If we learn from our mistakes I'm getting a great education!
RE: Synchronous Motor & Need for Rotor Earth Fault Protection
----------------------------------
If we learn from our mistakes I'm getting a great education!
RE: Synchronous Motor & Need for Rotor Earth Fault Protection
Scotty, for the big generators (like that you have) I think must use 64R protection with level of signal( about 10kOhm) and level of trip( about 1kOhm). More from that, only injection principle.
It's additional cost, but you sleep good.
From bad exp of one nuclear power plant with generator 1000MW, rotor e/f---half year of repair.
Regards.
Slava