Comment on trying to test washing machine motor; saw a white flash, voltage dropped, what happened?
sj_zero 6 days ago
I feel like if a motor is showing resistance properly, the "safety capacitor" is a spot I'd look, since caps can fail pretty easily, especially at 220vac. You'd just get a replacement and try that.
diyrebel@lemmy.dbzer0.com 6 days ago
Right but I think that safety capacitor (SC) is the last thing I care about. IIUC, I could perhaps even simply bypass the SC because it’s merely improving the power quality. It’s not worth buying an SC if I fail to fix whatever else is broken. If I could get the machine working, I could then of course consider replacing the SC as a final protective measure.
The task at hand is testing every essential component of the washing machine, starting with the motor and tacho. I would like to understand what happened with the SC and motor though. Did I wire the motor wrong which caused the SC to flash and produce bad output for a moment? I don’t want to repeat that. I could power the motor directly without the SC, but if the motor is doing upstream damage then I guess I wouldn’t want my breaker box on the chopping block.
dgriffith@aussie.zone 6 days ago
Possibly your motor is having an insulation breakdown when 220v is applied. Looks fine when testing with an ordinary multimeter and it’s low supply voltage.
So everything looks fine until it powers up. This flashover would likely fry whatever control components are in your main board, and it’s possible that your safety capacitor has a set of polyfuses in it that temporarily go high resistance when excess load is applied.
To check for an insulation breakdown you’d really need a megger which can apply 250/500v to the motor windings to check the leakage to ground/between windings.
diyrebel@lemmy.dbzer0.com 5 days ago
Thanks for the feedback! So I guess I should buy a megger. Wow… not cheap. I think I see these at local 2nd hand street markets. I often thought “what strange multimeter… so few functions” but I didn’t realize what I was looking at. I will look for something that dials “500V” and has fewer modes than a multimeter, and ideally a “MΩ” printed somewhere although it looks like they won’t all print that on the device.
I suppose I could try to bring the motor into an appliance repair shop and pay them to test it with a megger.
As far as diagnosis of the whole machine-- suppose it’s true that I have an insulation failure. The control panel LEDs light up correctly when powered on, then when I try to start a program the start button just blinks. Does it seem viable or likely that faulty insulation would cause the controller to behave that way? I get the impression that the blinking LED means the controller detected an unspecified fault of some kind & refused to continue, which tempts me to think that the controller is functioning correctly – unless it’s a false positive of a failure.
I really want to avoid replacing multiple major parts because I don’t imagine I can return special ordered parts.