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Is there a way to make a DC motor spin more freely? Answered

I have a 36V, 15.5A, 450W  PM dc motor that i would like to use in a wind turbine, but is has quite a bit of resistance when spun by hand.  what mods can be done to change this, if any?

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boondocker

Best Answer 8 years ago

Depending on the size of the prop you're going to hang on the end of that thing, it may not be as big an issue as you think. The torque will always feel greater with the palm of your hand than with a long lever arm. Maybe weight the ends of the turbine blades, if blade length is an issue?

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Re-design

8 years ago

Probably not.  It sounds like a high quality motor already and that means the bearings are probably high quality already.  The resistance you feel is probably the pull of the magnets on the armature.  The stronger the pull the stronger the magnets the better the motor more or less and the better the generator.

Is this a new or lightly used motor or are the bearings going out.  Is it a geared motor?

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SafetylastRe-design

Answer 8 years ago

It's quite well built, but the bearings stink.  it is slightly used; it's out of a 36V scooter.  i think you must be dea don about the magnets.

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kramerr

8 years ago

Generators have a lot of internal inertia and back EMFwhen their starting up. Once they get going its much easier to keep them going.

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seandogue

8 years ago

just remove those silly magnets. It'll spin like a top.

Seriously, assuming secondary friction isn't the culprit, (cruddy bearings, etc.) or, as MahavishnuMan suggested, an internally geared motor, that resistance to movement is the effect of your generator doing its job.

You could always drive it using a reducer to minimize the frictional loading seen by the prop

reducer (conceptual) ==> large wheel drives small wheel...large wheel connected to prop, small connected to motor shaft.

In other words, use a transmission.

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MahavishnuMan

8 years ago

It sounds like it might be a geared motor.  I was going to suggest using gears to reduce the necessary amount of torque (at the expense of lowered output due to less RPM's generated by the spindle).  If that's a satisfactory sacrifice to catch fainter winds, then go for it; otherwise, find a motor with less friction.