Motor rotation question

Re: Motor rotation question

John in NM

Not all motors are reversible, I would guess that one isn't.

He could flip it around if possible, which it may not be given the application.

twist the belt

Re: Motor rotation question

John McGaw

Lots of questions about just that subject online and sometimes no agreement as to the answers. I found this answer which seemed quite succinct (but it might still be wrong, of course):

"In a three phase induction motor, reversing any two of the three wires will change the rotation direction.

In a single phase induction motor, the direction is controlled by a starting capacitor. Change the pole on which it it placed will reverse the direction it starts and then runs in.

For synchronous motors, a shading ring (often copper) is placed on one of the armatures - swap the ring location to the opposite armature..

For universal motors, swap the wiring of the brushes."

I guess I've been lucky since, the few times I've needed to do it, there was a diagram readily available.

Re: Motor rotation question

Ellis Walentine

Thanks, John. I get the feeling that swapping the poles of the starting capacitor might be the best bet. I'll pass this along.

Ellis

PS He considered twisting the belt, but figured it wouldn't last long.

Re: Motor rotation question

Keith Newton

Sometimes the needed info is on the inside of the cover plate rather than the motor name plate. Its pretty easy to miss by removing the screws, lifting off and laying face down without ever looking on the underside.

Diagram

Ellis Walentine

Yes, Keith, and it's amazing what we miss. But, this is an old motor, with no schematics on the cover. Either the capacitor fix works or it doesn't. If worse comes to worst, he'll twist the belt or weld up a motor mount on the other side of the rig. Or, pick up a used motor that spins in the preferred direction.

Ellis

Re: Diagram

John K Jordan

Might also drop by a local motor repair shop an ask, if you have one. The guy at the shop here knows just about everything related to motors.

Re: Motor rotation question

ebd

Might be a dumb question, but ... Why does the direction of rotation of a cement mixer matter? Seems to me it would mix rotating in either direction. What am I missing?

I know

Dustmaker Mike

the paddles in the mixer are made to work counter clockwise. OK I am guessing.

Re: Motor rotation question

John in NM

On mine the fins inside are intended to rotate a specific direction. I think it is more to make pouring easier, but I suppose that depends on the mixer design.

Good info...

John in NM

Good post John, though some of those are too difficult to try. I never knew about swapping the capacitor leads, that is a really good one to know and super easy... I kind of wonder if its really that simple, but my motor theory gets a little vague to know offhand.

Re: Motor rotation question

Joe Kaufman

I do not believe that reversing the wires on the capacitor will change motor rotation direction. You need to change the relationship between the starting winding and the run windings, which usually means getting to those connections inside of the motor and reversing those connections. Not a simple task.

Re: Motor rotation question

Walter Ahlgrim

I agree with Joe swapping the 2 wires around on the start capacitor will not change the direction of the motors rotation. The only way is to remove wire around for either the start coil or the run coil but not both. This will require opening this motor and finding the connection tied to the coils and varnished in place.

It is likely less work to find another motor.

Walta

Re: You are correct!

Larry Clinton At Frankfort, (Central) Indiana

The wires on the cap will not reverse the rotation.

Reversible motors have four (4) wires coming out of the motor winding's. Two are connected to the "start" winding"s, two are connected to the "run" winding's inside of the motor. One of the start winding's is connected to one of the run winding's, these are both connected to one side of the "120V line, either hot or neutral.

The other start winding wire is connected to the capacitor. the other lead from the capacitor is connected to the starting switch. The other wire of the "starting switch is connected to the other run winding lead, then go to other side of the 120V line of the Line (ground or hot).

To reverse the motor rotation the 2 run winding leads must be reversed with relation to the 2 starting winding leads. IE: if you label the run winding leads "A" and "B" and the start winding leads "1" and "2" and wire "1" is connected to "A" and the current rotation is CW, hooking "2" to "A" and hooking "1" where "2" was connected the motor will rotate CCW.

It sounds quite complicated but really is very simple, just hard to put into words. The easy way to determine if a motor is reversible is to remove the rear end cap and see how many leads are coming from the winding's, if three it is not, (as one end of the start and run winding's are connected internally) if 4 it is made to reverse!

Thought that sounded a bit odd...

John in NM

But then I really don't have a good picture of motor function beyond that 4-field cartoon from physics class and rules of thumb.

Thanks for straightening it out.

try it

Bill Tindall, E.Tn.

"PS He considered twisting the belt, but figured it wouldn't last long. "

Maybe he should try it and see how long the belt lasts. I'll predict more batches of cement than will get made any time soon.