# Motor Spinning in Reverse!



## migreig (Aug 5, 2011)

Hello,

I have a 6.7" ADC mounted in my 91' Sprint and just hooked it up to 12V for the first time for a little test run to ensure everything is connected correctly. The thing is, no matter how I wire it, the motor spins backward. That is, the car moves forward in reverse and backward in the 5 drive gears. What could be causing this?

The motor came from a 1980 Renault Lectric Leopard.


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## palmer_md (Jul 22, 2011)

ah, French car.. explains a lot. haha. You say you tried wiring several ways, but you did not indicate how. How is it wired right now, and what other ways did you try? 

- Battery + connected to which terminal
- Battery - connected to which terminal
- Are other terminals connected directly together?


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## major (Apr 4, 2008)

migreig said:


> Hello,
> 
> I have a 6.7" ADC mounted in my 91' Sprint and just hooked it up to 12V for the first time for a little test run to ensure everything is connected correctly. The thing is, no matter how I wire it, the motor spins backward. That is, the car moves forward in reverse and backward in the 5 drive gears. What could be causing this?
> 
> The motor came from a 1980 Renault Lectric Leopard.


Hi there mig,

First off, congratulations on moving your EV under electric power 

The motor is probably the MTA-4001 Prestolite 7.2". It is a unidirectional motor designed to run in only one direction of rotation. Unfortunately it seems to be wrong for your new application. It is a compound wound motor and cannot be simply reversed by reversing polarity and has no provision to reverse the armature polarity with respect to the field. It would require internal modifications. And note it likely has the standard Prestolite brush advance for its rotation direction.

Regards,

major


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## major (Apr 4, 2008)

palmer_md said:


> ah, French car.. explains a lot. haha. You say you tried wiring several ways, but you did not indicate how. How is it wired right now, and what other ways did you try?
> 
> - Battery + connected to which terminal
> - Battery - connected to which terminal
> - Are other terminals connected directly together?


It is a 2 terminal motor, A & S.


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## Tesseract (Sep 27, 2008)

migreig said:


> The thing is, no matter how I wire it, the motor spins backward.....


Yes, that's how series motors behave. To change the direction you need to flip the polarity of the field (S1 and S2) in relation to the armature (A1 and A2). You do this by moving the jumper that connects the armature to the field to the other field terminal. Ie, if the jumper connects A1 to S1 then move it to S2.

Note, you also need to change the brush advance as it will now be retarded rather than advanced. I can guarantee you the motor won't last long with retarded brush timing.

EDIT - nevermind... didn't realize the motor only has two terminals so the direction is fixed.


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## migreig (Aug 5, 2011)

This is the motor

http://www.cloudelectric.com/product_p/mo-l91-4003.htm

It has 4 posts on it. This is a little unclear. Is this possibly just a result of how I am wiring it? I can't remember off the top of my head how I did. I did it according to a wiring diagram i found online. Is there a simple fix for this?


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## migreig (Aug 5, 2011)

http://www.diyelectriccar.com/forums/attachment.php?attachmentid=12401&stc=1&d=1331940830


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## major (Apr 4, 2008)

migreig said:


> This is the motor
> 
> http://www.cloudelectric.com/product_p/mo-l91-4003.htm
> 
> It has 4 posts on it. This is a little unclear. Is this possibly just a result of how I am wiring it? I can't remember off the top of my head how I did. I did it according to a wiring diagram i found online. Is there a simple fix for this?


That is not the motor from the "1980 Renault Lectric Leopard". So it can be reversed externally.


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## migreig (Aug 5, 2011)

I guess I should clarify. The motor is from that car, but I don't believe it's the original motor. I think the car was rebuilt in the late 1990s.


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## palmer_md (Jul 22, 2011)

ok, after going in circles about which motor ADC or otherwise were back to the question of how have you wired it currently and in the past?

See Tesseract's post above for how to reverse the direction.


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## migreig (Aug 5, 2011)

OK, I will try wiring it both ways and check back. If the motor spins correctly int he opposite direction, how can I know whether the brushes are correctly positioned, or need to be retarded or advanced?


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## palmer_md (Jul 22, 2011)

Not your motor, but the concepts are the same.

http://www.go-ev.com/end-users/005_004_SU050412_001_Motor_Wiring.pdf

and probably more info than you need...

http://www.cedengineering.com/upload/DC Generators and Motors.pdf


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## migreig (Aug 5, 2011)

I wired A2 to S2 and A1 to +, S1 to - and it worked properly this time. Obviously it was my mistake. Just to be sure, is there any way to ensure that the brushes are set properly.


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## migreig (Aug 5, 2011)

Thanks for that wiring info Palmer!


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## migreig (Aug 5, 2011)

Palmer: according to that information. Wiring it the way that I did should produce "counter clockwise at drive end" rotation. Is that looking at the shaft or from the motor down the shaft?

I am just trying to make sure that the brushes are set correctly for what I need.


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## major (Apr 4, 2008)

migreig said:


> Palmer: according to that information. Wiring it the way that I did should produce "counter clockwise at drive end" rotation. Is that looking at the shaft or from the motor down the shaft?
> 
> I am just trying to make sure that the brushes are set correctly for what I need.


It is sold as a reversible motor from what I can see. So it should be neutrally timed. Maybe you can check with Cloud. It is hard to visually verify, but the brush contact center line on the commutator should line up axially with the pole bolts (the 3 hex bolt heads in line on the frame) for neutral.


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