back-end motor overheating

[davemac]

i have a motor overheating and cannot chase the problem down...i have switched the stator out with another lane...i have switched gearboxes out also...the problem remains with the original machine...i have checked and replaced male and female plugs at the motor...checked the C-1 plug...pulled the pit out for inspection...when the machine is turned on the BE motor doesn't start as if there is a problem with SS or capacitor so both of those have been changed...i can turn BE switch off ,manually turn the pit motor,then turn switch back on and motor will start...then it gets so hot you cannot put your hand on it...i am getting 125 volts to the BE plug...help me before the man kicks me out!

[keeth]

This all sounds like a defective start switch,in one instance the switch is stuck in run when it wont start then in the other case where it runs and gets stinky hot the switch is stuck in start. Check the condition of the cent mech of the gearbox also make sure that the switch and the black disc are of the matching type. The large disc uses the bar type switch and the small disc uses the one that looks like a pointer.

[felix]

Just for kicks, try another chassis. Maybe a bad glass relay or socket.

[Table_Head]

You could also have bad bearings in the motor or the gearbox. With the power removed you should be able to turn the carpet pulley with little effort and the motor input should turn a lot while you do this. If it takes a lot of effort just to move the carpet pulley then your gearbox might have an issue.

[AMFDOCTOR]

Try changing the BE MTR relay in the chassis. Over time the fingers on the relay tend to flatten out and a very small air gap develops between the stationary and movable contacts. You'll really see this if you're usinging potential relays. Sometimes the relay doesn't know wich way to go because of this happening.

[Tablejam]

Hmm.. is it trying to run the other pit as well as the one on that machine?

[Table_Head]

Hmm.. is it trying to run the other pit as well as the one on that machine?

Could be I had that happen before, but if it is a national it would be able to handle it. Although I wouldn't recommend it, I has happened to me and it ran until I could get my spare lift in.

[davemac]

i changed the chassis but problem remains,searched all through wireways and did find a potential problem(screw lying between terminals) but that wasn't it...i changed the SS again just to be sure and the motor starts like it should now ,however it still gets very hot, CM is new and i made sure SS was opening and closing as it should...turning the pit by hand is easily done so i'm pretty sure there is no problem there(i did pull pit last week) also,the adjacent pit is not being run by this motor...thanks for all inputs and i will keep chasing for as long as the man lets me...

[slb785]

Sounds like something is putting an additional load on the motor causing the overheating. Check that your pinwheel spins freely by turning it by hand while power is off. also check that your ball lift moves freely as well while power is of.

[inthepits]

with how quick it gets hot I'm with Keeth, really sounds like its stuck in the start winding.

[BigClive]

I'm getting deja-vu from a similar recent thread. I'd also suggest checking that the motors start switch isn't jammed in the on state.

If you're not familiar with the use of a start winding in the motor then it's an extra winding that has the function of starting the motor by giving it direction and a stronger magnetic field. Although some single phase motors that use capacitors for rotation have the cap and second winding on continuously, many just use the start winding briefly, and when the motor is up to speed a centrifugal mechanism disconnects the start winding. If the switch is faulty and doesn't open, then the motor can get hot quite quickly and ultimately risk burning out.

Motor capacitors are also rated for either start or run applications, with the start capacitors being smaller because they are low duty, and the run capacitors being bigger because they are in circuit all the time the motor is running. If a start rated cap is used in place of a run cap then it will often overheat and may fail. This usually happens when someone buys the wrong capacitor because it was cheaper.

[AMFsupt]

I would try first was to run the motor without any load on or belts or drive shaft on. If it still overheats that was maybe something in the C1 plug, like pins burnt or the plug itself something just a little cracked inside.

[AMF Brian]

If it's not mechanical, don't forget to look at the wires going to the terminal block for the back end motor plug in the back end control box.

[Gym]

I have run into a few, more than I'd like to admit, of these. On mine it turned out to be that the end plate of the stator where the bearing rides was worn. Sometimes turning this can work; However, I ended up asking a friend, machinist guy, if he could re square it. He did with a bit of milling and an insert. Worked great!

[davemac]

i'd like to thank everyone for their inputs....what i found was bad connections at C-1 changed pins on both sides and seems to resolved the issue...again,thanks