Help with belt sander

[waldershelf]

I need some advice please, from someone who knows about electric motors. My belt sander has a starting problem, normally it starts, runs slowly then after a second or two speeds up and runs at full speed. However here's where I have the problem. Sometimes it just hums and doesn't start at all, sometimes it just runs at the slow speed and sometimes it works normally. When it's not starting properly if I give the belt a shove it will quickly run up to full speed. Can anyone diagnose whats wrong with it and what I need to do to fix it? TIA

 

[pedrobedro]

Does it have anything like a start/run capacitor ? It sounds like that is failing.

 

[Ton-up]

Are you talking about a bench mounted linisher type or hand held?

 

[gaz1]

you need a capacitor so the motor knows which way to spin
without it the motor just hums away while it decides, when you spin it you aid the motor therefore stopping its hum and it spins up

 

[bourbon]

what make is it? It could be full of debris and that's causing the issue

 

[waldershelf]

Thanks for the replies. Yes it has a capacitor mounted on the side of the motor. It's a bench top job with a belt and a disc. It came from aldi or lidl quite a few years ago.

 

[Climber]

I've had exactly the same symptoms with a garden chipper /shredder. It's pretty obvious when the capacitor goes on that.

 

[The_Yellow_Ardvark]

Thanks for the replies. Yes it has a capacitor mounted on the side of the motor. It's a bench top job with a belt and a disc. It came from aldi or lidl quite a few years ago.

I may have a spare one in the grave yard.
Can you pass me the details so I can look to see if we have.

 

[waldershelf]

Thanks for all the replies and cheers for the offer TYA I'll try and bum one off a "mate" if I can't I'll get back to you on your kind offer.

 

[brightspark]

ebay sell them for peanuts just check the voltage and how many uf

 

[RichardM]

Last one I swapped on my bench grinder was 5uf out of a florescent light fitting. Near enough for capacitance and works.

 

[waldershelf]

I stripped the cover off the capacitor and found markings suggesting 450v and 6uf. Managed to get hold of one and fitted it today. When I got the thing off I realised what I was looking at was a case and the actual capacitor was lurking inside. If you look at the picture you can see the diagnosis was bang on the capacitor shell is buckled and leaking. Fitted the new one and its running like new again.

 

[Climber]

I stripped the cover off the capacitor and found markings suggesting 450v and 6uf. Managed to get hold of one and fitted it today. When I got the thing off I realised what I was looking at was a case and the actual capacitor was lurking inside. If you look at the picture you can see the diagnosis was bang on the capacitor shell is buckled and leaking. Fitted the new one and its running like new again.View attachment 198260

Yep, I can confirm that ones definitely knackered.

 

[waldershelf]

Yep, I can confirm that ones definitely knackered.

 

[bourbon]

+1 for that not being too well.
glad it's sorted now