Re rating a Synchronous Machine
Re rating a Synchronous Machine
(OP)
We have a 9MW 4P 6.6Kv 60hZ Synchronous Motor, and we are thinking of using this on another plant where the frequency is 50 hZ. We know we will have to rate the motor for a lower power, but is this feasable. What are the issues we have to think about





RE: Re rating a Synchronous Machine
FAQ237-1224: Motors: Changing between a 50 and 60Hz supply.: Motors: Changing between a 50 and 60Hz supply, gives detailed analysis of this.
You would require to derate it for power & voltage to avoid cooling issues.
Additionaly probably you will need to find out the critical speed of the motor, incase it falls near the new rpm (in this case it is unlikely).
Anand Sekhar
RE: Re rating a Synchronous Machine
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If we learn from our mistakes I'm getting a great education!
RE: Re rating a Synchronous Machine
What is the rated power factor? usually its unity, but if not you may be able to run at a lower power factor.
I dont see any probems mechanically, unlikely to be near the critical speed and the bearings will be fine.
Where is it? Can u get ot to a repair shop and test it, see what it will do? Iknow one in the Uk that will do that for you and rewind if necessary