Anyone know 120V motors? (capacitor question) - Toyota Yaris Forums

CoryM · 10-22-2013, 04:30 PM

Thanks guys. Took it to work and now, of course, it is working fine. Capacitor it required to start the motor, and motor will turn if manually assisted. Do capacitors ever intermittently work? Took motor apart, it is brushless so not much to look at .

CTScott · 10-22-2013, 04:36 PM

Quote:

Originally Posted by CoryM

Thanks guys. Took it to work and now, of course, it is working fine. Capacitor it required to start the motor, and motor will turn if manually assisted. Do capacitors ever intermittently work? Took motor apart, it is brushless so not much to look at .

Caps can dry-out and as they do they lose their capacitance. It may be that the pump starts fine with no load, but with a load the capacitor may not be doing its job to start the motor.

CoryM · 10-22-2013, 11:28 PM

Drying out caps seems like a permanent thing, not a "works most of the time" thing. I'm just worried it's a bad section/transistor of the motor, and only doesn't work when stopped on that spot. It does, however, make the same sound with the cap unplugged as it did when it was in the machine and not working. I live alone so it's not like this dishwasher gets overused.... much to my girlfriends chagrin

That makes me think the capacitor is more likely, rather than the motor. I'll see what I can get a cap for locally, and if cheap enough, throw it in. Arg. I don't mind spending $60 but hate wasting money. It's not worth paying anyone to test anything either.

Cheers.

dj92 · 10-29-2013, 11:05 AM

I've had issues like this on our clothes dryer and a concrete tumbler.
Pleas note, these are not usual electrolyte capacitors with a conducting fliud inside!
Instead, it's some kind of oil.
The capacity loss is a result of inuslation failures between the aluminium sheets.
They are so thin that the short circuit burns away ("self healing"), but this always results in a capacity loss and one day the motor won't spin up anymore.
The ones I replaced smelled like having been fried in a pan as I opened them

I've replaced both with solid state foil capacitors and up to now they both work like a charm.
Capacity and voltage should match (voltage is the maximum allowable, so the value of the predecessor can of course be exceeded by the replacement capacitor), that's all, considering the flowing current is usually rather low.

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10-22-2013, 04:30 PM	#1
CoryM Drives: 2009 5-door, 5-speed Join Date: Sep 2011 Location: White Rock BC Posts: 687	Thanks guys. Took it to work and now, of course, it is working fine. Capacitor it required to start the motor, and motor will turn if manually assisted. Do capacitors ever intermittently work? Took motor apart, it is brushless so not much to look at .

10-22-2013, 11:28 PM	#3
CoryM Drives: 2009 5-door, 5-speed Join Date: Sep 2011 Location: White Rock BC Posts: 687	Drying out caps seems like a permanent thing, not a "works most of the time" thing. I'm just worried it's a bad section/transistor of the motor, and only doesn't work when stopped on that spot. It does, however, make the same sound with the cap unplugged as it did when it was in the machine and not working. I live alone so it's not like this dishwasher gets overused.... much to my girlfriends chagrin That makes me think the capacitor is more likely, rather than the motor. I'll see what I can get a cap for locally, and if cheap enough, throw it in. Arg. I don't mind spending $60 but hate wasting money. It's not worth paying anyone to test anything either. Cheers.

10-29-2013, 11:05 AM	#4
dj92 Embracing Curves View User's Garage Drives: '14 Prius Executive Join Date: Aug 2013 Location: mid-western Germany Posts: 256	I've had issues like this on our clothes dryer and a concrete tumbler. Pleas note, these are not usual electrolyte capacitors with a conducting fliud inside! Instead, it's some kind of oil. The capacity loss is a result of inuslation failures between the aluminium sheets. They are so thin that the short circuit burns away ("self healing"), but this always results in a capacity loss and one day the motor won't spin up anymore. The ones I replaced smelled like having been fried in a pan as I opened them I've replaced both with solid state foil capacitors and up to now they both work like a charm. Capacity and voltage should match (voltage is the maximum allowable, so the value of the predecessor can of course be exceeded by the replacement capacitor), that's all, considering the flowing current is usually rather low.