Need help troubleshooting reversing motor

Edit: fixed! See 5th reply


What I know: 1/2 hp capacitor start gear motor. Controlled by momentary push buttons (think winch/hoist with momentary buttons to spool out and spool in).

Tonight, when engaging in forward I heard a rapid cycling/clicking of the contactor. Releasing the button did not stop the cycling. I panicked and pushed the button to run it the other way which stopped the cycling. Motor would not re-engage in forward and I could not hear the contactor clicking, although I did hear a hum. Motor operates in reverse just fine. I replaced contactor for fwd direction and no change other than a more audible click of the contactor.

It seems the motor is a standard 4-wire reversible capacitor start motor. It may be dual voltage as there is a 5th (orange) wire that is capped. FWD direction white & brown are to line, black is to neutral, and yellow is to capacitor. REV direction has black & brown to line, white to neutral, yellow to capacitor.

I was hoping capacitor but I suspect not considering it works in reverse. Other thoughts? I hope not winding, it's a proprietary motor and the mfr of the system will only sell a complete motor assembly at a steep cost.

What should be ohmed to verify winding resistance?

Do you have a wiring diagram and/or nameplate for the motor?

The fact that it works in one direction would tend to imply that it's not a winding issue; the same windings are generally used for both speeds, just reversed.

Are you indicating that the FWD button engages the contactor properly but there is no motor movement, both FWD and REV contactors respond to the push buttons but only the REV contactor makes the motor respond? The FWD contactor has been replaced with a known good one? Are these all true?

Stuart

atomarc said:

Are you indicating that the FWD button engages the contactor properly but there is no motor movement, both FWD and REV contactors respond to the push buttons but only the REV contactor makes the motor respond? The FWD contactor has been replaced with a known good one? Are these all true?

Stuart

Click to expand...

True except the last, I did not verify the contactor was fully good. I know it clicks like it should. I have several of them so I'm going to verify proper operation then install another contactor. That being said, I think contactor is fine bc if, while the motor is spinning REV, I hit the button for FWD the contactor will engage but bc of existing REV momentum motor will continue in REV. Which tells me it's getting power through the FWD contactor circuit. It just won't rotate.

I did get some more info from a vendor that sells replacement parts. He says it's a baldor 6-wire motor. He sent a diagram but it doesn't match what I have so I'm going to have to sit down and see what is going on.

That being said, what internally changes in the motor to reverse direction?

No nameplate, I thin OEM of this removes it to force replacement procurement through them (they won't even share any troubleshooting or P/N's, they will only talk to you if you pay a $250 svc call plus mileage (80 miles one-way to my place). Vendor of replacement parts has a 3/4 hp motor with no capacitor or contactor that he says is much better and more reliable, drop in replacement. Only $1400!

I'm not a motor guru so take this with a grain of salt. A typical single phase, reversible motor has only one start winding and one run winding. Reversing is accomplished by electrically reversing the connections to the start winding.

IMHO, if the motor will run in reverse but not in forward, it proves the motor windings are intact but that the connection to run forward is bogus..the FWD wiring or contactor has failed in some manner.

This could be proved by switching wires to make the FWD contactor command a REV rotation. That will tell the story.

Stuart

atomarc said:

I'm not a motor guru so take this with a grain of salt. A typical single phase, reversible motor has only one start winding and one run winding. Reversing is accomplished by electrically reversing the connections to the start winding.

IMHO, if the motor will run in reverse but not in forward, it proves the motor windings are intact but that the connection to run forward is bogus..the FWD wiring or contactor has failed in some manner.

This could be proved by switching wires to make the FWD contactor command a REV rotation. That will tell the story.

Stuart

Click to expand...

The one odd thing that I can't wrap my head around is that the switching is not on the leads with the cap. So is it a start cap internal (on the switched leads) and an external run cap?

Either way, you were right, running in 1 direction but not the other indicates windings are fine. To rule out contactor issues I bypassed the contractors and push buttons and direct wired the motor for FWD operation and flipped the breaker on. Motor ran FWD. I did find the problem. The contactor is made up of 2 individual Allen Bradley contactors that are held together by molded plastic jumper assemblies on each side that consist of multiple wires in exact positions to jump power leads on the input side and motor leads on the output side. Upon close inspection, 1 of the leads on the REV contactor side had been stressed and broken and thus power to the run winding wasn't getting where it needed to go when the FWD contactor was energized. The only explanation I have for it suddenly stopping is that the stress point was thinner and I recently had an overloading issue that may have further damaged that section of the jumper and vibration did the rest. I didn't catch this because I never loosened the terminals on the REV contactor, I just loosened them on the FWD and gently wiggled the contactor free to replace it. Cut that broken jumper and put a wire in and voila!

You can reverse *either* the start winding *or* the run winding. It looks like they're reversing the run winding in your case.

Good to see you've got it fixed.

SomeoneSomewhere said:

You can reverse *either* the start winding *or* the run winding. It looks like they're reversing the run winding in your case.

Good to see you've got it fixed.

Click to expand...

I had wondered that but every tech article I could find stated the start winding was to be reversed. It's working now so I'm happy! Wife is happy we don't have to drop $1400 on a new motor!