Any use for a 1.5hp DC motor?

[Toller]

My old treadmill wouldn't sell, so put it out by the street; but first pulled out the motor.

Why a DC motor, rather than AC? Is there anything in particular it is good for, other than a treadmill?

[Frank]

Makes great drive for a BBQ spit. Great speed control. Frank

[Chris Friesen]

Just visited a shop where a guy used the same type of motor (with a power supply from ebay) for a continuously-variable-speed drill press.

Chris

[Chris Lewis]

According to Toller :

DC because it permits you to vary the motor speed to anything you want. Largish AC motors (eg: 1/6HP+) are usually locked to line-frequency.

Especially useful in lathes and other woodworking equipment (like the drillpress someone else mentioned). Without a DC motor, you're stuck either changing belts, or using highly complex variable pulley arrangements (similar to snowmobile and automotive CVTs) to change tool speed.

Highschool electric car projects too, tho, those are usually 12 or 24V.

Should have pulled out the control electronics too. Together, in working condition, it's worth a fair amount.

[Toller]

I did put out the controls; fortunately there is even a wiring diagram. It seems small for a 1.5hp motor, but is a GE. Are DC motors smaller and AC? My lathe has a 1/2hp motor on it. Would this be a reasonable replacement; assuming I can get the right size pulley?

[Chris Lewis]

According to Toller :

The wiring diagram won't be of much use unless you're into doing your own electronics. _Without_ the matching speed controller this thing may be useless (eg: rev too fast for your application). DC motor top ends are usually considerably higher than equivalent AC induction motors, and without the controller, it won't regulate speed very well under load (or at all).

Usually.

If you still had the controller board and could jury rig the thing, probably. Without it, hard to tell.

If the motor has more than two wires and an obvious ground wire, I think you're screwed without the control circuit.

[John Gilmer]

By "DC" I assume you mean than it has permanent magnet pole pieces.

Compared to a "universal" motor (which is a series field winding "DC" motor at heart), the permanent magnet motor "tends" to be constant speed with the speed proportional to the applied voltage.

The 1.5 hp rating likely has something to do with the supposed response to a sudden increase in load.

As another poster said, it would make a great drive for some shop machines. The "locked rotor" current can be quite high and there should be some means of shutting down power BEFORE either the motor or power supply is fried.

"They" make some cheap garbage disposals with such motors. I put one in my rental unit but it didn't last long. As I recall the motor didn't fail (I entertained salvaging the motor and the bridge rectifier) so I guess it must have leaked.

[Phisherman]

DC motors are much more expensive than AC motors. DC motors can vary in speed using a variable resistor, AC can not. DC motors are useful for buffing wheels, lathes, grinders, sharpening stones, sanders, etc. If your motor is a "Baldor" it's a very good brand.

[dpb]

Thanks for the idea -- hadn't crossed my mind. Next time the disilliusioned homeowner calls the local call-in free trader show w/ one, I'll pay more attention! :) Like Toller's, they're nearly always desperate to get rid of the things...

[Dave Martindale]

Permanent magnet DC motors are easy to control the speed of. Speed is proportional to voltage, while the current varies as needed to maintain speed as the load changes.

Old treadmill motors are favourites for converting small lathes to variable speed drive, both metal and wood lathes.

Dave

[gfretwell]

Why didn't you save the speed control from the treadmill?