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Patrick
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Joined: 08/01/2008
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Posts: 1

Posted: 06:14am 08 Jan 2008

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Hi: I'm seeking info on converting an older multi speed DC motor into a generator for my wind project. I have a field wound 180 VDC 1750rpm Baldor continious duty 1 1/2 hp motor. It has 2 sets of fields, on fairly light guage wire and one very heavy guage. I would like to convert it to a 12 volt generator, with maximum amperage so as to be efficent in my conversion. Any suggestions?

Thanks

Pat

pat

Gizmo

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Joined: 05/06/2004
Location: Australia
Posts: 5116

Posted: 09:23am 08 Jan 2008

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Hi Pat.

I think your going to have difficulty with that conversion. You would need to power up the field winding before you can get any power out, and thats going to be a big problem.

Someone else might have a few idea's. Treat it like a car generator, in the days before alternators.

Glenn

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herbnz

Senior Member

Joined: 18/02/2007
Location: New Zealand
Posts: 258

Posted: 03:21pm 08 Jan 2008

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Hi
The unit you have as stated above requires a DC sopply to excite the magnetic fields. It is what is known as compound main field smaller wire is feed with supply volts unfortunity 180V needed problem if only have 12v.
The other heavy winding goes series with soupply provides boost as load comes on

Herb

KiwiJohn
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Joined: 01/12/2005
Location: New Zealand
Posts: 691

Posted: 01:18am 09 Jan 2008

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As has been pointed out by Herb and Glenn your motor needs field excitation before it would work as a generator.

However, DC generators, including the type that were once common on cars, may have residual magnetism and if you spin your motor with a meter across the armature you may see a voltage. If you connect your armature in series with the heavier gauge field winding there might be something useful there.

According to my minimal understanding if you put 12volts on the field windings you will get 12volts on the armature when turning the motor at a few hundred RPM but the output in watts will be only a fraction of what was consummed when it was a motor, something like 50 to 75 watts.

Unless you can find someone who has experience with a similar motor I think the best course of action is to put it on a bench connected to another motor or in a lathe etc and just do some experimenting!

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