Starter capacitor

[poweritup]

Hi all,

I’m trying to repair my potato peeler and have spotted this little burned out capacitor inside. I noticed the melting in the top corner which also melted away some of the wire touching it.

These capacitors I’m having trouble finding. It has the resistor at the top also.
Anyone help with which I could use to replace this.
Images of the original capacitors below. hoping to find some alternatives as the originals are hard to find and cost 60 quid from supplier.

Thank you in advance.

 

[James]

RS PRO Polypropylene Film Capacitor, 440V ac, ±10%, 25μF, Screw Mount | RS

uk.rs-online.com

 

[Darkwood]

Replacing the starter maybe a solution to the cause but it maybe that the motor is faulty and not switching out the starting cap which is not uncommon in a old cap' start motor, replacing it is pretty cheap so see it it occurs again, if so then there is probably an issue with the centrifugal switch or the motor is simply not getting to speed due to other friction/torque based issues.

 

[Marvo]

RS PRO Polypropylene Film Capacitor, 440V ac, ±10%, 25μF, Screw Mount | RS

uk.rs-online.com

With a voltage rating of 440 the capacitor you've linked is more suitable as a a run cap, I wouldn't recommend it as a replacement for a start capacitor. I'd suggest a voltage rating of 275VAC or lower would be suitable.

 

[James]

With a voltage rating of 440 the capacitor you've linked is more suitable as a a run cap, I wouldn't recommend it as a replacement for a start capacitor. I'd suggest a voltage rating of 275VAC or lower would be suitable.

What is the reason behind this?
I am not trying to argue the point, just trying to learn. my possibly incorrect knowledge of these things is that the voltage rating is irrelevant as long as it is high enough to cope with the voltage applied. over spec should make no difference??

 

[Lucien Nunes]

I'd expect the film cap to be physically larger but if it will fit, should work fine. For electrical work a higher voltage rating is invariably better and will last longer, provided that size and cost are not an issue, and a film cap is invariably more resilient than an electrolytic. In electronics, it's not advisable to use electrolytics with vastly inflated voltage ratings, e.g a 100V rated cap in an application that will only ever see 3V, because in the long term the loss of oxide layer thickness (unforming) can cause the value to increase and affect reliability.

Looking at the OP's pics, I don't think the melting was anything to do with the capacitor itself. It seems to have been the bleeder resistor that has cooked, which reinforces Darkwood's suggestion that the centrifugal switch might be stuck shut or the winding faulty.

 

[poweritup]

Thanks for all the replies and info guys. Really appreciate the expert knowledge.

Ill probably order the genuine replacement for £25 quid after searching high and low to find it so I don’t cause any further damage.

fingers crossed it all plans out.

good day.