no load motor tests

[majuba]

Good day

I am busy testing a 6.6 kV, 1 MW, 121 Amps AC motor with no load. I am interested to know what no load current should I expect? What % of full load current is expected and will it reach full load current?

Thanks in advance.

 

[Baldor]

Someone on this board a little craftier than me may be able to answer that, but the easiest way to find the no-load current is to ask the manufacturer. I've tried to calculate this in the past and have never been 100% accurate. There's just too many variables.
When I can't get the unloaded(or magnetizing) current from the manufacturer, I'll simply run it at rated frequency and voltage and measure it.
The more poles the motor has the higher the magnetizing current will be, as low as 20% of FLA or so for a 2-pole, and as high as 60% for a 4-pole.

 

[electricpete]

I agree with Baldor.