Bosch Washing Machine won't ever spin to full speed

[chrisken]

I have a Bosch WFO 2460 washing machine, as it begins to spin it will not increase speed ( you can hear it reining itself back) so the laundry is still dripping when you take it out. I have replaced the motor brushes, which were worn down to 10mm. Now it will spin properly to full speed when it is empty; but as soon as it has laundry in, it will not go to full speed.
I was thinking maybe uneven load would make this happen, but I have tried lots of different loads and still no joy.
Any help gratefully received, thanks in advance. Chris

 

[Bankrupt]

Could the belt be slipping ? Did you change the brushes with the motor in-situ or did you remove the motor ?

 

[chrisken]

Hi Bankrupt, thanks for your reply. I replaced the brushes with the motor in situ, good thinking but I don't think it is the belt as you can hear the motor backing off speed and I am not sure if this would happen if it was a slipping belt. Chris

 

[big-all]

part blockage [filter or pump]when draining stopping the fast spin as the water level hasn't lowered enough ??
try a fast spin with a load off clothes an 1 gallon /5L off water

does it wobble./shake more than normal when it tries a fast spin?

 

[chrisken]

Thanks Big All, I have tried your suggestion, first I filled machine with with 5 litres of water but no clothes and the spin worked fine at full speed. Then I put in a load of clothes and 5 litres of water and spin did not get to speed, the machine gave up trying after 5 minutes with 7 minutes left to run on the timer. Then as another test I put in a really small load of dry clothes (1kg) and no water, but still the machine would not spin upto speed and again it gave up and stopped with 7 minutes left to run on the timer.
The machine does not wobble or vibrate but I can't help thinking that there is some sensor that is shutting down the spin or possibly for some reason the motor cannot take the strain of a load spinning and reins itself back. Could it be that the uneven load sensor has become over sensiitve, has anybody any idea where it is and how I could check it. thanks

 

[cjapeterborough]

I would check the brushes again -the contact angle might not be good and/or brushes not
moving freely in the holders(wet n dry).

If the armature is damaged or uneven then this can also mean the motor will
have trouble under load and/or higher speeds.

When you changed the brushes was their any scoring/scratches on the armature?

With the rear plate removed can you see any arcing when running?

Sometimes the motor gets damaged if the brushes wear down to the copper braid
and despite best efforts has to be replaced (approx 1 in 10 go this way
imho)

 

[JohnD]

I don't know about washing machines but I know a high-speed machine that checks for out-of-true wobble, and slows down the motor if it detects the device is out of balance.

Your speeding up/ regulating down motor noise fits the pattern.

It might be that you have either an uneven load, or worn bearings, or loose counterweights, or uneven feet, causing the drum to get out of true. Or perhaps the out-of-true detector is faulty.

 

[cjapeterborough]

I am pretty sure the machine does not have any logic to decide whether it is
wobbling or not.........if bearings or weights were a problem then it would be very obvious.

Afraid motor gets my vote.........seen it myself on a couple of Bosch machines this year which I had hoped
would be simple brush replacements.

Unfortunately if you keep perservering with a bad motor then at some point it will short/overload and take out the board.

 

[chrisken]

Thanks CJApeterborough, I will take the motor out and check armature (couldn't see it before as I changed the brushes in situ). I have checked for sparking with the back plate off and there was none apparent. If it turns out that the motor has had it, do you think it is worth spending £160 to £200 on a new motor for a nine year old washing machine??

 

[cjapeterborough]

If the armature has any scoring -usually directly in the middle-then it is unlikely to recover.

Can you hear any ticking or clicking when the motor runs?
Again sure sign of the brushes bouncing on the armature.

Its a good machine and built to last -you would need to spend
towards £400 to get a new equivalent at least.

If it was me I would lookout for a Bosch/Siemens motor 2nd hand
eg Ebay...or do a google on casaparts.
this strategy requires time though and washing can pile up I guess!

You may even get lucky and pickup a donor machine.

£200 is simply a ridiculous price that is set to get you to buy a new machine.......

You need officially part number 141875 or 144797 however its highly likely
that a 1200 spin Bosch/Siemens from any of the models will fit especially when made in Germany imho.
ie WAE/WFL/WFO/WFX etc and Extraklasse etc.

I know the WAA motors have longer shafts and wont fit though.

 

[Leccy758]

You would be paying around 50% the cost of a new machine for that motor and at the end of the day the rest of the machine will still be a nine year old one, Bosch W/M are designed for around a 10 year life.

The speed sensor/out of balance circuit on the PCB could be faulty which would double your cost.

Does it spin up to full speed when set at a lower speed, was fairly common on Electrolux boards would spin at full speed when empty but not with any load at all, would spin ok when set to lower speed/short spin cycle though.

 

[chrisken]

Thanks for your help everyone, I think I have finally solved it. It was the motor, I cleaned the commutator with a piece of really fine emery cloth stuck to the end of a thin piece of wood which I then stuck down the hole where the brushes go, put the brushes back in and it spins full speed with a load now. I guess the problem was a bad contact between the brushes and the armature.