# # of motor power connectors



## BenNelson (Jul 27, 2007)

What determines how many power connectors there are on a motor?

My Etek motor on my motorcycle has 2 - one for positive and one for negative.

The motors I have on the electric forklift I am dismantling have two connections for the pump motors, and 4 connections for the drive motor.

I see that most the motors being used for EVs have 4 connections.

Can somebody please explain the difference to me?

Does the number of connections have anything to do with wether or on it is a series-wound or shunt wound?

Please help!


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## Twilly (Jan 22, 2008)

Most motors have 4 windings. 2 field windings, and 2 windings on the armature. In a 4 terminal motor, the field windings are wired to 2 terms, and the armature windings are wired to 2 terms. In a 2 term motor, the field and armature windings are connected in series inside the motor, and because of this, no matter how you wire the motor, the direction will always be the same because it is not possible to reverse the polarity of the field in relation to the armature.


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## BenNelson (Jul 27, 2007)

OK, I think I get it.

That's why on 4 terminal motors, a short cable connects two of those terminals, to put the field windings and armature in series.

So it sounds like my two terminal motor should work ok, I just need to use the reverse gear on the car.

Oh, and pray that the motor spins the right direction for the transmission of whatever car I end up putting it in.


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## Twilly (Jan 22, 2008)

I think that 99 percent of ICE's turn CCW when looking at the crankshaft output to the transmission. I think Hondas are odd balls. Hook 12 v to your motor and find out... If it is wrong, you might get lucky and be able to open the motor and reverse the field polarity, or else a pro will need to get involved.


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## BenNelson (Jul 27, 2007)

I have heard that about Hondas too.

I think I just need to test this out and then buy a Metro if it spins the one way, and a Civic if it spins the other.

There is still one more motor to pull out of the forklift. It is the drive motor. It's a little smaller than this pump motor, but has four power connections on it. I assume that the other end of those cables goes to a reversing contactor and that's how you make the forklift drive forward or reverse.

I think I want to use the largest motor I can out of the forklift. If that one won't work, then I will use the drive motor.

Not sure which would be cooler, just shifting into reverse, or having a big red button on the dashboard that puts the car in reverse.


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