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230 mtr using 110vac

230 mtr using 110vac

230 mtr using 110vac

(OP)
I have tested several 208-230vac mtrs using 115vac and they spin. Is there any reason not to do this? I know the rpm is less. Might the mtrs expire pre-maturely, and if so by how much? Might they overheat?

RE: 230 mtr using 110vac

If you are using 115V (120V) these are probably single phase motors. If they spin up and the centrifugal switch operates quickly there is probably no problem.
If the motor is very slow to accelerate, the start winding may overheat at even 50% voltage.

Bill
--------------------
"Why not the best?"
Jimmy Carter

RE: 230 mtr using 110vac

(OP)
yes, Im talking single phase. I have heard that some 3 phasers run on single, but I have not tried that....yet....

RE: 230 mtr using 110vac

Good! Don't! Three phase motors will not start on single phase. They just burn up.

Keith Cress
kcress - http://www.flaminsystems.com

RE: 230 mtr using 110vac

Speed on an AC Squirrel Cage motor is dependent on supply frequency and the number of poles in the motor winding; voltage has no direct effect on speed.

But voltage has a dramatic affect on torque and loss of torque MAY influence the speed indirectly. In fact the motor torque varies by the square of the applied voltage change from it's design, so by giving your motor 1/2 voltage the motor torque will be cut to .52or 25%.  

Unloaded, a motor only needs a small fraction of it's rated torque output to spin the mass of its own rotor, so because the frequency is correct it may indeed spin at the correct speed. But motors are "dumb animals". As soon as you put any appreciable load on that motor it will be unable to keep it spinning, the motor will slow down, the slip will increase and it will pull so much current in an ATTEMPT to get to normal speed that it will burn itself up.


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