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Motor speeds according to poles

Motor speeds according to poles

Motor speeds according to poles

(OP)
I was looking for a table of speeds of 3 phase motors according to no of poles for 50Hz.  Does anyone know the whereabouts of one of these?

RE: Motor speeds according to poles

n = f/p

where n = rpm
      f = frequency - cpm
      p = number of pairs of poles

So :

2 poles - 3000 rpm
4 poles - 1500 rpm
8 poles - 750 rpm etc
 
(synchronous speeds - ie not counting slip)

RE: Motor speeds according to poles

agreed.

Although the f in the numerator has not been clearly defined.

I would prefer to say sync speed = 2*FL / poles
where FL is line frequency.

Put the units in and you'll see the need for any additional required unit conversions such as 60rpm / hz.

Actual speed for general purpose NEMA design B motor is required to be in the range 0-5% below sync speed, and usually in the range 0-1% below sync speed.

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