How to diagnose/fix a motor?

[dbhost]

Have you considered trying to find the windings / brushes / bearings for the existing motor? Many of these old tools are well worth rebuilding if you can get the parts, and many of the parts are standard off the shelf stuff...

If it were mine, I would take it to a local electric motor rebuilder to see what they could do for it...

[master53yoda]

Motors that have less then synchronous speed listed are listing the speed when delivering rated HP. NO electric motor will deliver rated HP with out operating below the 3600 or 1800 RPM most 3600 are 3450 at rated HP and most 1800 are 1725 at rated HP.

Electric motors will deliver the required torque to the load if the hp need is less then it will just deliver that which is needed. If the load is 5/8 hp that is all that a 3/4 or 1 hp motor will deliver. the real problem is that the 1/2 hp motor will deliver the 5/8 hp as well but it will smoke in time.

As stated before do not use a lower HP motor because you will burn it up.. Most induction electrical motors will deliver 150% of rated HP but will burn up if operated at the load very long. The miss representation that has become common in compressors is an example of this.

[chopnhack]

Thank you Lchien and Masteryoda. Very informative
I hadn't thought about it Dbhost b/c I figured labor would be more than the motor is worth. If its smoking and smelling like burnt electrical (insulation? resin to hold windings) I was thinking about diagnosing it, but as mentioned before, if its smoking, its likely that the windings are starting to short each other out. It would be cool to just pull the rotor/windings out and drop in a new one, but I don't know where to look for that around here. I will check the phone book under electrical motors and see what I find. Maybe on Friday I can call around.

[Stytooner]

http://www.surpluscenter.com/item.as...tname=electric


http://www.surpluscenter.com/item.as...tname=electric



Depending on your rotation.

[chopnhack]

Skytooner! that would be awesome. I have to check out which way my motor rotates. That would be an awesome deal as long as it fits and shipping's not a killer. Thanks!!

[Daryl]

Skytooner! that would be awesome. I have to check out which way my motor rotates. That would be an awesome deal as long as it fits and shipping's not a killer. Thanks!!

Be wary of the first one, it seems to have a short, splined output shaft.

[Stytooner]

I didn't catch that. They do have many more types of motors. I have bought lots of stuff from them including motors. Reasonable shipping.
This page is all reversible motors.
http://www.surpluscenter.com/sort.as...c&keyword=MBAD

[chopnhack]

You know, I was thinking about that lower rpm motor with pulley change, but was thinking, doesnt that reduce horsepower to the blade? Can't just create free energy, right

[LCHIEN]

You know, I was thinking about that lower rpm motor with pulley change, but was thinking, doesnt that reduce horsepower to the blade? Can't just create free energy, right

not really, you exchange speed for torque, the pulley puts it back right exchanges torque for speed.