Sweep Motor Buzzing when returning from guard position

[ReddFoxx]

First things first. We are working with Omega-Tek single boards, and Westinghouse motors. We are having a hesitation accompanied with buzzing coming from the sweep motor when the machine attempts to return to home position from guard. While I was away on business, the pinchaser swapped motors with a known working unit with the same results. He also swapped chassis. Now that I finally got to look over the situation, I was dumbfounded to find that the chassis he moved onto this lane caused the (s1) sweep run finger to operate backwards. When the finger is all the way back, the lane would run and then stop when it came to the high spot on the lobe. My guess is that our previous head mechanic made a mistake with the chassis wiring while replacing burnt pins and that would be the issue. Anyway, that chassis works fine on lane 3 where we pulled it from. Now, my question is, What would cause the motor to hum and heat up when trying to return home? I know sometimes they will do this when you have a bad capacitor. My pinchaser did say he checked out the capacitors with a multimeter, but didn't see any issues. Also this only happens when it is attempting to return. I would guess this is because it is working against gravity to lift the sweep. Any help would be appreciated. Thanks!

Kevin Blaney
General Manager
Valley Worlds of Fun
Fairmont WV 26554

[Grit]

When you say "S1 sweep run finger to operate backwards" are you saying the SA cam lever is running the sweep until it stops on the high side of the cam? Since you said its running backwards it sure makes me inclined to say your sweep reverse switch needs looking at. which could be part of your problem with the humming since its part of starting the sweep motor.

if you've got everything going in the right direction, crank your sweep through and feel for any binds. Let us know what you find out.

[ReddFoxx]

I do apologize for the misunderstanding. Without being too technical, the sweep cam finger on the leftmost position is the one I was referring to. With Chassis switched, the sweep cam microswitch seemed to be operating opposite from the way it normally does. This must be a wiring issue in the Chassis, as it does work fine on the lane it came off of. What I did notice that I was not happy with is the fact that one of the counterweights used on the centrifugal starting switch is missing, and I believe this is what caused a small part of the gearbox fan assembly to break off. Would this be a problem?

[felix]

Armature winding and rotating switch I'd worry about. A small part of the gearbox fan assembly to break off should not make much of a problem.

[slb785]

Something is messed up in one of your chassis. Try that chassis on another lane and see if you get the same result. Sounds like you are going to have some fun trying to figure the wiring issue out. Ive come across multiple things on my machines where they were wired improperly, which makes diagnosing and repair almost impossible. can take hours with a continuity tester to sraighten it out. Not fun

As for your motor issue. Sounds to me like your cent. mech. is sticking. If you say it threw a weight then it should be replaced. change the gearbox or replace the cent. with a good one and im sure your problem will go away

[AMFDOCTOR]

ALSO CHECK YOUR CAPACITORTS

[keeth]

Redd you stated that the pinchaser changed the motor with a known good one,did that include the gearbox or just the stator? If it was just the stator the faulty cent mechanism can still be left behind. If you can, plug the table cable in there and see if that circuit can power it from all 3 stopping and starting positions without grunting and groaning.This can tell you if it is a mechanical or electrical issue.
Does multiple chassis operate "backwards"on this lane or on lane 3? The one lane that only operates with its own chassis has two wiring issues to counteract each other,probably something like 2 c2 pins in each side of the plug mismatched to make its own little world seem ok

[BigClive]

I'd also say double check the capacitors on the motor, since the phrase "My pinchaser did say he checked out the capacitors with a multimeter, but didn't see any issues." means absolutely nothing if any start/run capacitors weren't actually swapped out. Make sure that centrifugal switch is actually operating on the motor too, since a continually energised start winding will potentially burn out the motor. As the others have said too, check for mechanical resistance during the phase of operation that's causing the humming, since a high load will make the motor hum and heat as described.

[ReddFoxx]

Wow guys, I do appreciate the quick response and I will definately jump on these as soon as possible. I am kind filling in as Head Mechanic right now. I have spent quite some time on these machines over the years, but I try to shy away from the more in depth things like chassis work. I will double check the capacitors as well. The way I was taught was to use a screw driver to release the electrical charge, then use a multimeter across the two terminals and see if it builds resistance to infinity. Is this the best way to test these? Once again, thank you all for the advice. Hopefully i'll have things back up in a jiffy!

[BigClive]

The resistance change technique is very rough and ready that at least checks if the internal safety mechanism inside the cap hasn't opened. (often visible externally anyway.) The correct way to test a cap is to measure its capacitance and ESR (Equivalent Series Resistance) with a suitable meter, but another really good test is just to swap it with a spare.

I take it you all do keep at least one spare in stock to minimise machine down time?

[Gym]

Chassis, Stator, Caps. Swap the chassis with the neighbor. Swap the stator with a known working one. Check to make sure Cent Mech is secure and flat. Partially engaged start winding's are an overheat. Swap the caps.