# One controller, two motors?



## Woodsmith (Jun 5, 2008)

I hope this is a simple question.

I have two small 24v wheel chair type gear motors.
I am getting a Curtis 1214 controller 36-48v

Can I run both motors from the one controller? 
Should I wire them in parallel or series?

I am planning on coupling the motor shafts together to double the 'oomph' for a project.

Cheers.


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## major (Apr 4, 2008)

Woodsmith said:


> I hope this is a simple question.
> 
> I have two small 24v wheel chair type gear motors.
> I am getting a Curtis 1214 controller 36-48v
> ...


Yes, yes, and yes.

How's that for a simple answer 

More than likely, they are PM commutator motors. Since you have the shafts coupled mechanically, both have the same RPM. So in series, the motors will each see half voltage from the controller, but have the same current. If in parallel to the controller, each will see full controller output voltage and each will draw half of the controller output current.

Of course, running a 24 V motor at higher voltage will make the RPM proportionally higher for a given load. Series? Parallel? Up to you 

Regards,

major


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## Woodsmith (Jun 5, 2008)

OK, that's simple then I can play without fear of damaging anything.

I will need to see what happens to the motors in series and parallel with the 24v, 36v and 48V as I don't know what speed I want yet.

Thanks Major.


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## Qer (May 7, 2008)

You can also arrange them as a series/parallel shift and use that as a kind of electrical low/high-gear. Start in series, when acceleration starts to drop off release the pedal, shift to parallel and hit throttle again.

Firework's guaranteed if you shift with throttle applied...


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## Woodsmith (Jun 5, 2008)

Interesting option, Qer. I know of that but hadn't considered it.

What I am thinking is this.

I am getting a remote transfer box from a Lada Niva. It has an input flange and a front and rear output with a locking diff and two gear ratios, 1.2:1 and 2.135:1.

I was thinking of either using a biggish golf cart motor (which I am also getting) on a chain drive or both the small gear motors together on a chain drive to the input. That would let me sort out the gear ratios.
The outputs would then be used to directly drive lawn tractor wheels as a two speed trans axle with locking diff.
The Curtis controller has electrical reverse circuits so I can go both directions.

The whole thing would be mounted on a simple chassis with a pair of steering wheels at the front, some batteries and a seat.

Then I would have a small tractor/tug to play with and I won't have to use my car for shunting my trailers and trees around.


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## Qer (May 7, 2008)

Then I'd say you want to run the motors in parallel, run the motors as fast as they can handle and gear them down to a sane pace. Then, when you need more force to trail stuff, you can shift them over to "low gear" to be able to move even with heavier load. Just make sure you don't overheat the motors in series mode. Running high current at low rpm will mean higher losses and you might have to cool the motors by forcing air through with an external fan.

Oooor you could add a normal, mechanical gear box? Then you can just hook them up in parallel and let the gears convert rpm to torque.


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## Woodsmith (Jun 5, 2008)

Qer said:


> Then I'd say you want to run the motors in parallel, run the motors as fast as they can handle and gear them down to a sane pace. Then, when you need more force to trail stuff, you can shift them over to "low gear" to be able to move even with heavier load. Just make sure you don't overheat the motors in series mode. Running high current at low rpm will mean higher losses and you might have to cool the motors by forcing air through with an external fan.


I will probably do this as I don't need lots of speed but I do want to learn about what I can do with motors, controllers and different ways of throwing electrons about.



Qer said:


> Oooor you could add a normal, mechanical gear box? Then you can just hook them up in parallel and let the gears convert rpm to torque.


That is what I would have done in the past but I want to keep it simple and cheap. The Tbox will be sideways so the front output does the right wheel and the rear output does the left wheel. It gives me a diff and a diff lock, one up on most little tugs.
One step down ratio with a chain drive between motor and Tbox will be fine, fast walking speed and slow walking speed when the throttle is fully open.


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