# Reversing a 2 pole DC motor for reverse



## Randeb56 (Apr 6, 2015)

Just wondering if there is anything that can be done to get my odd Thrige motor to switch into reverse? It's all wired internally to turn clockwise only. Because of the Smart car design putting it in reverse in the manual tranny is a bear to access. Has a stepper motor of some sort and was controlled by a computer. May get it to work but it won't be easy. 
I heard someone mention 'double Alderson connectors' on a project they were working on, what are they?


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## Sunking (Aug 10, 2009)

Randeb56 said:


> I heard someone mention 'double Alderson connectors' on a project they were working on, what are they?


Not for certain but sounds like the same kind of switch a Series Golf Cart uses for reverse. It is a mechanical switch and reverses the polarity to the motor.


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## major (Apr 4, 2008)

Randeb56 said:


> Just wondering if there is anything that can be done to get my odd Thrige motor to switch into reverse? It's all wired internally to turn clockwise only. Because of the Smart car design putting it in reverse in the manual tranny is a bear to access. Has a stepper motor of some sort and was controlled by a computer. May get it to work but it won't be easy.
> I heard someone mention 'double Alderson connectors' on a project they were working on, what are they?


You need to nose around on this forum and do some searching. There is a useful sticky thread on forklift motors. You can pick up the terminology and common parts used.

You have a 4 pole motor. Poles refer to the magnetic poles inside the motor; N-S-N-S. It has 2 terminals for the power connections. Since it is a wound field motor, this makes it unidirectional. To reverse rotation, you must internally disconnect and reverse polarity of the field relative to the armature. This is best done by a motor rebuilder or machine shop who knows what they're doing.

Your motor was the pump motor from the forklift and therefore unidirectional. It is possible it is compound wound which would complicate control. That forklift would have used a traction motor which would be series wound and reversible (4 terminal). Any chance it is available?

Anderson connector? Most guys use the model SB350 or SB175. Sometimes the charger uses a SB50. http://www.waytekwire.com/products/12/Anderson-Connectors/


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## Randeb56 (Apr 6, 2015)

Good info. Thanks. I guess I'll have to figure out that stepper motor to get the tranny to reverse. Good to know.


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