Tumble Dryer start capacitor

[pintglass]

Hi

I've just had to replace a belt on our tumble dryer which had snapped.

Upon testing the dryer the motor will not start by itself but will happily run if i push the drum to begin with, which lead me to test the start capacitor.

The capacitor rating is 9 uf 450v ac +/- 5%, testing capacitance with my multimeter gives me a reading of 8.5 uf which is just under the lower end of its tolerance.

Would this small amount be significant enough for it to not be capable of getting the motor running?

[sam_sam_sam]

Re: Tumble Dryer start capacitor

Some of these motors have a switch that at low speed start winding with the capacitor and when it gets up to speed it takes this winding out and goes to high speed winding

This switch sometimes hangs up and does not switch back to the low speed or the low speed winding it open

If this motor one of these switches take some brake cleaner with the dryer unplugged from the wall and clean the springs for the switch and then oil it fan motor oil in other words 5 weight machine oil

Make sure that the spring switch works freely

[pintglass]

Re: Tumble Dryer start capacitor

The motor does have a third wire going to it will this be for the switch?

[redwire]

Re: Tumble Dryer start capacitor

What make and model is the dryer?
You likely have a run capacitor and a start switch. But that's more than three wires...

[pintglass]

Re: Tumble Dryer start capacitor

I've attached a few images of the motor.

Sorry just realised the start capacitor is not installed, that obviously connects to the red and black wires that are hanging down.

[R_J]

Re: Tumble Dryer start capacitor

Can you here a relay click when you push the start button?

[pintglass]

Re: Tumble Dryer start capacitor

Yes it does make a clicking sound, but motor won't run unless i push the drum first then it runs fine.

[stj]

Re: Tumble Dryer start capacitor

meter the windings - probably o.k. but worth checking

[pintglass]

Re: Tumble Dryer start capacitor

Sorry I've never tested motors before.

Do you mean check voltage on them, is the motor housing my ground reference.

[R_J]

Re: Tumble Dryer start capacitor

Yes it does make a clicking sound, but motor won't run unless i push the drum first then it runs fine.

Do you have a meter? if you do, check the a/c voltage between white and red wires, you should have full mains, then check the voltage between white and black while pushing the start button, if you have voltage when you press the start button, check for an open motor winding, if there is no voltage, you could have a bad connection on the relay or plug wiring coming from the control panel.
If you want to check the motor resistance, check between white and red and white and black, it should be low resistance

[pintglass]

Re: Tumble Dryer start capacitor

I have put the capacitor back on then with the machine plugged in and switched on with the power button but the start button not pressed, I only get a few volts which is falling between red and white.

I've tested resistance and get about 30 ohm's between red and white but get OL between white and black

[R_J]

Re: Tumble Dryer start capacitor

I suspect the motor winding could be open, white should be the common, I suspect Red must be the main winding, and Black could be the start winding.
Do you read any resistance between Red and Black on the motor?
It could be like this diagram (this is from a reversable motor model)

[pintglass]

Re: Tumble Dryer start capacitor

I'm getting a high reading that's jumping around of about 4 Mega ohm's

The readings I'm taking are from the wires connected to the motor but are also connected to the control board should i be disconnecting them from the control board.

[R_J]

Re: Tumble Dryer start capacitor

I would disconnect it, but the readings for a motor winding are usually very low, One winding will be the main run winding and one should be the start winding and it seems like the start is open.

[redwire]

Re: Tumble Dryer start capacitor

Hotpoint TVF770G Aquarius tumble dryer 95687010000, also goes by Indesit, Ariston, Cannon, Creda, Proline etc. I could not find the service manual.
But looking at another model, the motor has two windings and the control board seems to have a relay to do the start/run switching.

The motor might actually be OK, it's just the rolling load is too high. The belt might be installed wrong or too tight and I would check the support rollers are not worn out or need lube, the dryer is level. Otherwise a new belt will just wear out fast.

Check the huge safety recall on it too.

[pintglass]

Re: Tumble Dryer start capacitor

What could cause this to happen could I have damaged it while changing the belt I had to use a lot of force on the shaft to get the belt on.

[pintglass]

Re: Tumble Dryer start capacitor

Hotpoint TVF770G Aquarius tumble dryer 95687010000, also goes by Indesit, Ariston, Cannon, Creda, Proline etc. I could not find the service manual.
But looking at another model, the motor has two windings and the control board seems to have a relay to do the start/run switching.

The motor might actually be OK, it's just the rolling load is too high. The belt might be installed wrong or too tight and I would check the support rollers are not worn out or need lube, the dryer is level. Otherwise a new belt will just wear out fast.

Check the huge safety recall on it too.

The belt did seem tight to get on, but i have been assured its the correct belt for the machine, all it does is raps around the drum and then round the motor shaft.

I'm unsure now what could be the cause of this as @R_J has said i should have low resistance between red and black.

If i remove the belt and start the dryer would this indicate the motor is ok if it starts by itself of would the fact that it has no load mean the start winding is unused.

[redwire]

Re: Tumble Dryer start capacitor

You should get continuity, a reading of a few ohms. With the motor unplugged, white-red should be a few ohms and white-black as well. black-red should roughly equal the sum of the two.

If you get open circuit, then you might have tugged on the motor's wires and broken a connection somewhere, have to look hard or take the motor apart to fix.
It needs the start winding to get going with drum and clothes as a load. A motor will start up with no-load, belt off even though no start winding connected.

[pintglass]

Re: Tumble Dryer start capacitor

The motor won't start even with the belt removed unless I help to get it going.

[redwire]

Re: Tumble Dryer start capacitor

WAIT this motor is reversable?