Thread: Sewing machine motor problem

Arron, historical forum discussions on Singer sewing machines may help as I have no idea.

This are just some suggestions - if you are not really familiar and comfortable dealing with AC mains powered stuff I suggest the $4 loss is not worth the risk

I presume the pedal is one that controls the speed if so it could be a problem with the pedal speed controller.

I would start by removing the pedal from the situation and try applying the power direct to try motor. This is not as easy as it sounds because I know they mostly used proprietary moulded plugs and sockets so you need to find you way around this.

Is it a plain motor? or does it have some sort of electronic box attached. Those motors sometimes have a load adjustment circuit whereby they allow more current when loads increase. This could also be a problem. Look for burned or overheated components on any boards is usually a place to start and if you find any replace them. However, unless you are familiar with electronics then there's probably not much that can be done.

Whatever you do be careful.

Very common fault 99% it's the brushes or the motor is saturated with oil and worn belt debris disassemble the motor and clean it especially the commutator, if this does not fix the
find a new motor, plenty of Chinese generic replacements available you may find some one who can rebuild it although it will most likely cost more that the entire machine

Need some more details Arron. Model no. would help

Originally Posted by NCArcher

Need some more details Arron. Model no. would help

Singer Capri Model GL 340

So I took this a bit further tonight.

I swapped the foot pedal for another, no change.
I disconnected the motor by removing belt, motor turns over easily, and the drive train of the machine turns over effortlessly as well.
Then I ran motor with no load (ie belt off) and it ran smoothly.
But reconnect the belt and the variable speed thing continues.
Belt tightness to spec.
Ran it hard for a while, to see if that lubed it up. It didn’t.
So I removed the motor, with the intention of disassembling it and doing the things China advised. However it’s obviously designed not to be tampered with, so I was hesitant to go further. Brushes not accessible either.

Image of motor attached.

I’m thinking the motor is just knackered. No big deal, it is pretty easy to use as is. Still I’ll fix it if I can - so any last comments?


D73971BD-EA4D-4A1C-AE3C-F5A03D3E6C1B.jpg

looks like some one has already replaced the the motor at some stage, is this a electronic model if so could be the circuit board, you will need to find a electronic technician
to trace the fault

Originally Posted by China

looks like some one has already replaced the the motor at some stage, is this a electronic model if so could be the circuit board, you will need to find a electronic technician
to trace the fault

What makes you think it’s a replacement ?

Plus I can’t find a circuit board - disassembled a bit more looking for it.

It's not the belt developed hard spots from being in the same position for ages? And being harder to get around the pulley at the hard spots?
Have you tried loading the motor by holding something against the pulley, so that the load is constant, and seeing if it still runs consistently?

Originally Posted by arose62

It's not the belt developed hard spots from being in the same position for ages? And being harder to get around the pulley at the hard spots?
Have you tried loading the motor by holding something against the pulley, so that the load is constant, and seeing if it still runs consistently?

No, belt is Ok, and the timing of the variations is longer then a single belt revolution.

I haven’t tried putting the motor under artificial load. I will do that.

just looks like one of the generic Chinese replacements Singer will usually have Singing on the name plate

I you have can of contact cleaner and compressor what about giving it a couple of long squirts and then a good blow?
Maybe wait for China and NCArcher comment on that first?

Originally Posted by China

just looks like one of the generic Chinese replacements Singer will usually have Singing on the name plate

It does, on the lhs. I guess I should have turned the motor around till it was in the photo.

BTW, I was using the machine today while recovering some dining chairs. It’s really very nice to use. Very tractable.

Cheers
Arron

Originally Posted by BobL

I you have can of contact cleaner and compressor what about giving it a couple of long squirts and then a good blow?
Maybe wait for China and NCArcher comment on that first?

Couldn't hurt to give it a squirt but I'm not sure if it will help. My guess is that one of the windings is damaged/worn out. It sounds like it is failing under load. It may have gotten a bit too warm at some stage and a section of the insulation is breaking down as the current increases. Only a guess but I can't think of anything else that would cause a regular cycle. Although.....if it is full of lint it may be getting hot under load and causing the problem. Try blowing it out with compressed air as Bob suggested