Electric Mower Motor for bike

General Discussion about electric bicycles.
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markz   100 GW

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Electric Mower Motor for bike

Post by markz » May 03 2014 7:48pm

Hello, has anyone done this kind of conversion for an electric bike. Around here these things are a dime a dozen. 2 kinds the corded mower and the battery powered mower, they are either free or ultra cheap. The corded ones I believe have a bridged rectifier. I couldnt find much on them, but I found something here about corded mowers stating "The peak output from the rectifier is about 170 Volts DC from a 120 Volt AC input."

I believe the battery mowers run in the range of like 24V to 36V with 12A's. They are of the permanent magnet variety. Dunno how much amps they draw.

I wonder how much these puppies weigh.

Other ideas I stumbled across was office equipment (old photocopiers), 24 Volt starter motors which wont do much good but worth the research, and a couple other ideas I wrote down on a piece of paper that I dont have handy right now.

dnmun   100 GW

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Re: Electric Mower Motor for bike

Post by dnmun » May 03 2014 10:24pm

you are correct. the mowers which run on 120AC have a diode to make DC current for the motor. the winding wires are tiny and could not handle the currents needed to drive the mower blade if the voltage was 24V DC.

torqueon   1 kW

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Re: Electric Mower Motor for bike

Post by torqueon » May 04 2014 8:36am

I built my bike using a brushed motor off a 24 volt ryobi cordless mower, running on 36 volts. Its good for about 600 watts continuous and fairly peppy from a stop.

However this type of build is not easy to do, since you need at least a 12 to 1 reduction on 26 inch wheel. The motor is 9 lbs.

The biggest problem I have with this built is finding replacement brushes.

markz   100 GW

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Re: Electric Mower Motor for bike

Post by markz » May 07 2014 9:47pm

Where did you mount yours?
I read the newer emowers are rocking out at over 1kW.

I was thinking rear rack mount, sprocketed.

What kind of off-the-shelf, cheap DIY motors are good?
Treadmill Motors are out.
I had my hopes on the electric mower idea, still is viable though.

Was thinking I could put a couple motors in series on one chain. Found a surplus store, that sells AC and DC motors, some with torque ratings that have a decent cheap price. The specs are kind of hit and miss but all I look for is the weight, and torque rating. Found some wheelchair motors, with reduction already installed, havent really looked into it too much, been busy with my school.

999zip999   100 GW

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Re: Electric Mower Motor for bike

Post by 999zip999 » May 07 2014 11:01pm

Hub motor kits are cheap and get you on the road fast.

torqueon   1 kW

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Re: Electric Mower Motor for bike

Post by torqueon » May 08 2014 9:33pm

The motor is under the rear of the seat and tire. Between the motor and wheel is a 2 stage reduction, on the left side. This is the best I can describe in words. I have pictures , I have tried to post, with no success. Sorry

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Ykick   100 GW

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Re: Electric Mower Motor for bike

Post by Ykick » May 08 2014 10:00pm

markz wrote:Hello, has anyone done this kind of conversion for an electric bike. Around here these things are a dime a dozen. 2 kinds the corded mower and the battery powered mower, they are either free or ultra cheap. The corded ones I believe have a bridged rectifier. I couldnt find much on them, but I found something here about corded mowers stating "The peak output from the rectifier is about 170 Volts DC from a 120 Volt AC input."

I believe the battery mowers run in the range of like 24V to 36V with 12A's. They are of the permanent magnet variety. Dunno how much amps they draw.

I wonder how much these puppies weigh.

Other ideas I stumbled across was office equipment (old photocopiers), 24 Volt starter motors which wont do much good but worth the research, and a couple other ideas I wrote down on a piece of paper that I dont have handy right now.
Last weekend I put a volt meter across the brushes of my B&D MM875 corded 12A mower and saw about 140VDC while spinning. 'been wanting to power it with old RC Lipo so I wanted to see what the motor sees.

Kinda the reverse of what you're thread is about but figure and hope this tidbit of voltage data might be of use?
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