Electronic – How to safely discharge this capacitor with broken wire

capacitordischargehigh voltage

My electric lawn mower won't start, upon inspection some wires got loose and damaged by the motor.
broken wire

It's a 20µF 500V capacitor. Normally I would try to short the pins with a screwdriver, but as you can see one of the pins is not connected anymore.

I don't have a power resistor. Can I try to put the leads of a light bulb socket with an incandescent light bulb to the connector + wire?

I'm used to dealing with low voltages, but I'm a bit hesitant to "mess" with a (probably still charged) high voltage capacitor.

After discharging, can I just strip the wire, heatshrink & solder the wire to fix it?

Best Answer

I would take a 0.25W 10k ohm resistor, hold the ceramic body gently with a pair of pliers, bend the legs so that they will fit between one connector contact and the nick in the wire and hold it between the two. Keep in in place for a second or two, and once done use a voltmeter to check the voltage across the same two points. When it is properly discharged it should read less than 1 volt. If it reads more, repeat the above.

If you use a piece of wire / screwdriver / other short circuit you will pull a huge current (for a short amount of time) from the capacitor - you will see this as a momentary arc (spark). This could damage it - it is certainly not designed for arc discharge given the application you have pulled it from.