Sincronous Motor fault
Sincronous Motor fault
(OP)
Hi I´m working with a 9600hp 40 poles (180rpm) sicnronous motor with a brushless exciter.
My question is: is possible to drive this motor to a extreme condition of 200% of nominal current and 160rpm by increassing the exciter volt?
This was a real condition, and I´m trying to figure out if the problem is on the brushless exciter or is an overload condition
Thanks
My question is: is possible to drive this motor to a extreme condition of 200% of nominal current and 160rpm by increassing the exciter volt?
This was a real condition, and I´m trying to figure out if the problem is on the brushless exciter or is an overload condition
Thanks





RE: Sincronous Motor fault
If sync speed is 180 RPM, then to get to 160 rpm you had to have pole slips. This could be caused by severe mechanical overload (although you'd think there should be protetion to trip the motor in this case) or very low field current. The only way I could see high field voltage causing a problem is if perhaps it resulted in rotor pole damage? (just thinking out loud).
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RE: Sincronous Motor fault
respectfully
RE: Sincronous Motor fault
It seams that a higher field current drive the motor to a higher stator current but I don´t know if is possivel to reach 200%
RE: Sincronous Motor fault
Look for mechanical overload to cause both under-speed and high current.
respectfully
RE: Sincronous Motor fault
Assuming the machine was in synchronism, raising the field current will increase the reactive output of the machine. It is quite possible to reach 200% stator current given a powerful enough exciter and a sufficiently stiff utility connection. A weak utility connection will experience a voltage rise which will limit VAr export; a stiff connection will absorb VAr's without a significant rise in terminal voltage.
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RE: Sincronous Motor fault
RE: Sincronous Motor fault
Anything else is likely to result in some bad odors coming from your motor. The amortisseur winding is not meant to do much besides give starting torque, and therefore does not have thermal characteristics suitable for extended operation. It'll melt down pretty quick.
old field guy