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Counting motor poles

Counting motor poles

Counting motor poles

(OP)
Hi guys & gals!

Could someone please clarify this for me......

Motor Poles,
I think I am confused. A motor pole is not necessarily one winding is it? If it were then surely a three phase motor can have a minimum of 3 poles not 2 as there is a minimum of three windings inside.

I have a diagram here with a Y connected supply and this is meant to be a 2 pole motor but I cannot understand where the poles start and end!!

Any help would be appreciated.

Thanks

Kev

RE: Counting motor poles

In simple terms, 2pole means 2poles per phase. Your 3ph motor has 3, 2pole circuits in it, one for each phase. Pole numbers are only divisible by 2. i.e. 2 4 6 8 etc. Increasing the number of poles increases the number of coil groups in each phase circuit and reduces the speed.

RE: Counting motor poles

A motor pole is not necessarily one winding is it?
Typically, Yes. A two pole motor has a North winding (group) & South winding (group). And the reason I say typically is there are whats called "consequent pole" motors. Which I doubt you have.

If it were then surely a three phase motor can have a minimum of 3 poles not 2 as there is a minimum of three windings inside.
There is a minimum of SIX in a three phase motor. Three phases, multiplied by two poles, equals six GROUPS.

I have a diagram here with a Y connected supply and this is meant to be a 2 pole motor but I cannot understand where the poles start and end!
Are the leads numbered?
What leads have continuity?


RE: Counting motor poles

(OP)
Thanks to both of you for that.

RE: Counting motor poles

Yup.  All correct.

The reason for the terminology 2-pole comes not from looking at the electrical side (how are the windings arranged) but from looking at the magnetic side.

A 2-pole motor has a rotating field with two magentic poles (N and S if you will).  We can in theory produce that same type of magnetic pattern with a variety of windings, 3-phase, single-phase (has a forward and reverse rotating field... each two pole)4-phase (if it existed) etc.  


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RE: Counting motor poles

(OP)
Thank you to everyone that responded. I nowunderstand a bit more about motor poles and motor theory.

Motors = Extremely complex subject!!!!!!

thanks again it was a great help

Kev

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