# DC Motor Hacking/Conversion question



## Clyde (Jun 11, 2010)

Hello!


I have a 36v DC motor that is rated at around 18 amps, which comes to just about 650w. Unfortunately this is not quite enough to get my motorbike moving, even without me sitting on it! Are there ways I can modify the motor to produce more torque?

Thanks


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## DavidDymaxion (Dec 1, 2008)

What about feeding it more voltage?


Clyde said:


> Hello!
> 
> 
> I have a 36v DC motor that is rated at around 18 amps, which comes to just about 650w. Unfortunately this is not quite enough to get my motorbike moving, even without me sitting on it! Are there ways I can modify the motor to produce more torque?
> ...


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## major (Apr 4, 2008)

Clyde said:


> I have a 36v DC motor that is rated at around 18 amps, which comes to just about 650w. Unfortunately this is not quite enough to get my motorbike moving, even without me sitting on it! Are there ways I can modify the motor to produce more torque?


Hi Clyde,

Maybe you can modify the motor. I guessing it is PM commutator DC motor. Usually more torque means more copper, more magnet, more steel or combination thereof. Usually results in a bigger motor.

Unless you have an awfully big bike, a 650 W (.87 hp) should move it. You need to have it geared properly. And you need to have the proper electrical feed to the motor. I bet you have something screwed up aside. 

I had a 1/4 hp motor on a small 24 V 3 wheeler which would do about 10 mph with my fat butt on it. Even at 12 volts, it would putt around slowly.

Regards,

major


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## Clyde (Jun 11, 2010)

Having much less experience in electrical engineering than I would like to have, it is INCREDIBLY likely I've screwed something up.

I think this same motor/battery combination would definitely be able to move the average bicycle + myself quite nicely, but the motorcycle I'm trying to convert is somewhat heavier...

Changing the gearing would probably be a good start, since the rear wheel does spin very fast if I hold it above the ground but otherwise it's acceleration is negligible.


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## major (Apr 4, 2008)

Clyde said:


> Having much less experience in electrical engineering than I would like to have, it is INCREDIBLY likely I've screwed something up.
> 
> I think this same motor/battery combination would definitely be able to move the average bicycle + myself quite nicely, but the motorcycle I'm trying to convert is somewhat heavier...
> 
> Changing the gearing would probably be a good start, since the rear wheel does spin very fast if I hold it above the ground but otherwise it's acceleration is negligible.


 
Post up some pictures and facts about what you have for ratio, contoller, battery, etc. Good chance someone here can spot something amiss.


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## Clyde (Jun 11, 2010)

I have a pair of 12v batteries- which I wired to a switch and the motor. The motor is 36v and is rated at about 18 amps. The gear on the motor shaft is 10 teeth. (I haven't gotten to counting the numerous teeth on the rear gear, which is attached directly to the wheel.)

--I'll post more info later today...


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