RCD trip on hotpoint washing machine

[Midge]

Folks,

Just to add to my list of jobs to do this weekend (sigh!) the washing machine decided to trip out the RCD on my distribution board mid-wash a short while ago.

Obviously a genuine fault as its reproduceable every time I plug the machine back in, but I noticed it doesn't trip the second the machine is plugged in as a hard cable fault might - it's more like 4-5 seconds after, during which there are the normal power/cycle indications.

Sticking my DMM across live and eth at the plug, I'm getting a reading which toggles between about 4K ohms and 1.4M ohms every second. Any ideas what might be at fault?

TIA Midge

[Harry Stottle]

My first guess would be the motor brushes worn down.

[BigGirlsBlouse]

The changing in resistance that you observe is in my opinion a mains interference suppressor that includes a capacitor, hence the change in readings. The capacitor also serves to improve the power factor which an inductive load like a washing machine motor presents across the supply.

[Midge]

Thanks folks - I'll let you know what I find...!

[Midge]

Well it's fixed but I confess it most certainly WASN'T what I was expecting!

Basically the connectors on the bottom of the control board were wet due to water getting across from the powder draw. I'd say bit of a design flaw and if I get a min, I'll post a link to some pics in case anyone else hits this problem. The machine is a WMA31 Aquarius.

Thanks again for the pointers.

Midge.