Sewing Machine Help!

[nathan211]

Hi all,

first post here go easy on me.

I have a sewing machine that im attempting to repair, iv'e checked over all the motor that runs the belt but on inspecting the foot pedal it seems like a capacitor in the pedal has popped.

Symptoms are the machine will run for around 20 seconds or so then it will trip the breaker. Almost as if its getting too hot and theres some sort of thermal cut out. The motor turns freely by hand theres no alot of resistance.

Question is if this capacitor had gone faulty why would the machine work at all?

I dont know how to identify capacitor resistance etc so i will upload a picture of what i have.

I was hoping it would be a solder out and in job.
Thanks for taking the time to read this all
Nathan

[Andrew F. Ali]

Re: Sewing Machine Help!

That is a start/run capacitor for the motor. You MUST get the correct replacement else you end up burning the Motor. The two red wires and one black is two caps in one casing.

[R_J]

Re: Sewing Machine Help!

It is likely a arc suppressor cap across the line, does one lead go to chassis and the other two go across the line and neutral?
The machine should work without it but you may not be able to listen to your AM radio at the same time.
This should be the replacement

[Andrew F. Ali]

Re: Sewing Machine Help!

Yes that looks like what I was thinking of.

[momaka]

Re: Sewing Machine Help!

Interesting arrangement. It could indeed be an arc-suppressor car, as R_J suggested. Though, if the machine doesn't work because of this, maybe it's also possible that it is some kind of a start/run cap.

In any case, you can see there are three caps inside this one cap: 2x 5.0 nF and 1x 0.1 uF. You could probably use 2x 4.7 nF Y-caps and 1x 0.1 uF X-cap, all rated for 250 VAC. Just connect them in the same way as the diagram that R_J posted above and all should work well.

[stj]

Re: Sewing Machine Help!

it's called a "Delta Cap", they are just for noise suppresion.
i used to see them in vac cleaners.

2 wires to the motor contacts, one to the body/earth

[Behemot]

Re: Sewing Machine Help!

It's also called input filter, you can often find some which also have common-mode coil in them, forming a complete input EMI filter.

That machine has it's own circuit breaker or? If it is asynchronnous motor there may be the starting cap inside the motor. It is also possible the startup (or even the main) winding developped a short.