Elec. Motor ??'s

[SteveR]

In reading this, please keep in mind a fifth grader knows more about electical than I do .

I purchased a couple of used grinder/polishers at a garage sale awhile back ($5/ea. ). Finally have a use for one. This one is a two speed (1750/3750 or close to that) and regular plug in outlet (110) and it turns the wrong way. Usually they spin toward you or downward. This one spins away or upward. It does not have a capacitor on the outside that I can see.

I opened up the bottom to take a look at the wiring. From the plug in, one wire goes to ground, the other (I will call it the switch wire) goes to the switch (low/off/high) wth a whole slew of wires for the switch itself, and the "last" one goes to a set of two wires. There is an identical set of two wires on the other side. Can I simply move the "last" wire to the other set of wires to get it to rotate correctly? Could it be a simple as this? I can get a pic if this would help.
Thanks in advance!
Steve

[cabinetman]

A picture might be a good start.

[Daryl]

I think if the motor was reversible it would have a diagram or other instructions inside the cover plate.

[eezlock]

electric motors

most electric motors are reversible, they will have the wiring diagram
on the contacts cover or on a plate riveted to the motor itself. The plug you described may be a 20 amp plug instead of a standard 15 amp plug, that is why it looks different or strange. Post some pics if you can, may be more able to help from that. eezlock

[SteveR]

No pics yet

Thanks for the responses.
I will check the plate/cover to see if there is a diagram. It is pretty filthy with white residue......I think it belonged to a dental/denture/orhto type person as I got a box full of dental tools with the grinder/polishers. I'll get it cleaned up better now since it sounds like this is do-able. If there is nothing I can see, I'll get a pic up.

An odd thing about this unit I have not come across before. The shafts are slight tapered, similiar to a morse taper on a lathe. They had a couple of keyless chucks mounted on them..after some playing with it, I discovered that there is a threaded collar right next to the main body that unscrews and forces the chucks off of the shaft. One of them is a Baldor and the other name escapes me now, but both appear to be old and heavy duty.
Steve

[LCHIEN]

Baldor makes motors and presumably the motor shafts in this case.

AC induction motors (which are usually used in grinder applications) cannot be reverses simply by swapping leads to the motor. The motor really has no way of knowing which is leading and lagging since they are simply out of phase with each other. Most induction motors use a starter cap to advance the phase of one winding of the motor to induce it to start in that particular direction.

The number of poles sets whether its a 1750 or 3500 RPM motor. In a dual speed motor, there whould be a switch that connects or disconnects the second set of pole windings.