Electric motor issue

Guys I picked up a pair of electric powered machines at an auction; after tinkering I got one to work with pets off both. My issue is that when the electric motor is "loaded" it clicks at the motor and stops/starts continuously. If there is no "load" it runs fine. Mixed reviews from people I've asked suggest that the starter in the motor is overloading (maybe but once it starts it shouldn't have to restart), the start capacitor is not large enough/too large, the windings are arcing and causing it to bind...

Any other thoughts?

In reply to chandlerGTi:

Has it only got a start capacitor or has it got a run capacitor as well? Usually a system with start and run caps will also have a switching mech of some type. If it starts ok and runs alright with no load it would indicate a faulty run Cap or switching relay.

If it only has a single Cap, then that Cap will be required to start and run while loaded, making a faulty Cap very plausable.

Outside of that, a potential short in either the armature or field windings or a sticking brush can provide similar symptoms.

Im sure you already know this, but be very careful with caps they can store energy longer than most realise and will give you one hell of a kick if you accidentally bridge them out. A big enough Cap can kill.

Thanks, it is just a start capacitor. How would I check what size capacitor it needs? Maybe the wrong one was installed at some point and is part of the reason it was kicked to the curb? It look new.

What kind of motor are we talking about here? Like a single phase induction motor with a internal starter? The starter in those is a flyweight setup that kicks the start circuit off when the motor nears it's running RPM, possible yours is gunked up or something, or the motor is trashed and you're bogging it down that far.

Yes, single phase 110. This is it, the cap sits in a shell that bolts to the housing like normal.

Capacitors usually have a stamping or sticker or the like that will tell you it's size in terms of farrads. Is there any available info on the cap? Alternatively, what's the machine?

Yugo also raises a good point regarding flyweights

Another thing is, if there is something in the machine itself that is excessively tight the cap may not have enough power to overcome the initial load.

If it starts itself its not the start cap (motor will run fine with a bad start cap, you just have to CAREFULLY spin it by hand to get it going), the cap does nothing once the motor is spooled up and you hear the switch click.

Is it possible something in your machine isn't right and overloading the motor?

Possibly, today I took the moving parts apart, made sure they were shimmed properly and greased/oiled everything. Same story.

This is the machine, it removes semi tires without much manual labor.

And here is a video of it under load removing a tire; it will still do the job but it isn't "right".

No video?

Weird, it was there

Video

Is it supposed to be reversing?

Yes, I ran it forward then reversed it. The clicking starts and stopes the motor as can be seen there but doesn't keep it from doing its job.

That looks like a run capacitor problem to me.

Is there an internal run capacitor? Usually it would have start and run next to each Other on the outside of the case right? There isn't one.

I think what you have is a start winding that is energised by a centrifugal switch, the click you are hearing. The capacitor is a run capacitor only.

So, the motor starts, the centrifugal switch shuts down the start winding. (click) The run windings take over, but with a bad run capacitor, the motor is out of phase and slows down to the point that the centrifugal switch closes again. (click) From there it's a cycle. Start, click, slow down, click, start, click...

I will admit that this is a guess. In your shoes, I would throw a capacitor on it and see what happens. They are cheap, and available at any real hardware store.

Ok, I'll pick One up. I believe I have one new one in one of the boxes of parts that came with it even. The one in it is a Dayton part so grainger supplied probably.

I'm pretty sure a motor like that with only one cap is always a start cap, but I could be wrong.