BOsch exxcel 1200 express

paulsa · 16 Apr 2009

HI There

I had a problem with our washing machine not spinning when full of clothes would spin etc when empty but not when filled with clothes. it did trip the circuit breaker once.

Changed the brushes but it will not wash or spin now the motor seems completely dead - fills with water drains but thats it.

The only thing I could think of was that the motor was knackered?

Any ideas - have i done something stupid (I made sure the plugs etc all went back the same way)

Help!

cakeman · 16 Apr 2009

try checking the tacho

its on the end of the motor with 2 very thin wires coming out

check theres no issues here

Leccy758 · 20 Apr 2009

Are the brushes the right way round
Are they actually touching the armature (some have little break off tags on them that need to be removed)
did a wire come loose in the motor plug
was the wiring harness pulled at all when working on machine (maybe a loose connection on the other end somewhere)

Tripping the circuit breaker could be a sign of further problems elsewhere or that the motor itself may be at fault

Ok just re read you got a bosch
Did you clean the brush holders out when you fitted the new ones and do the new ones move freely in the holders

poundfoolish · 4 Nov 2009

This thread seems to reflect what's been going on with my machine. leccy's replies look very encouraging ...

The background: machine gets seriously heavy use (averages at least 1 wash every day, approx 5 years old); increasingly reluctant to spin and sometimes to wash, the wife used the old TV repair method (hitting it); checked all the pipes downstream of drum, all clear, drain pump working, concluded the brushes were giving up. While waiting for new brushes machine stopped washing at all, let alone spinning (no drum movement). Replaced brushes; old brushes approx half cm long, showing braiding. Fitted new brushes. No change. Depression.

Tonight I will take out the new brushes and clean the housings (as suggested by leccy) which were pretty filthy (new brushes weren't moving freely, but sounded like they were in contact with the commutator (? don't really know what I'm talking about) and I think I got them in the right way (longest edge furthest from the spindle).

Leccy/anyone have any further suggestions about what other problem(s) it could be? I'm reasonably competent, and happy to try testing to find out the bust bit. All help v gratefully received.

Leccy758 · 4 Nov 2009

depending on the motor you could have a thermal fuse in the motor case

you should have 6 wires to the motor connection plug from the motor.

2 go to the brushes
2 go to the tacho 'thin wires'
2 go to the windings and go through a thermal fuse

if you have a multimeter check each pair, you should get a reading on Ohms. spin the motor armature when you do this and the resistance should change.

if the windings pair is open circuit I would assume thermal fuse blown

poundfoolish · 8 Nov 2009

... but it won't spin properly.

As I said in my last post I checked the bushes again and found that one wasn't properly installed and wasn't making contact. A bit of delicate filing and it now seats properly and the motor runs again. So far so good, it washes BUT it won't spin. It's like it tries to spin but can't get going and reverts to agitation. Repeats twice, reverses, reverses again and gives up, the timer going from 10 minutes to 1 minute then 0. Have tried this half a dozen times.

The motor makes a different, sort of whining, noise. I presume this is because the brushes aren't bedded in and should improve? Will power and the ability to spin also improve.

The old bushes were very worn, and I notice there are marks where they contact the spindle. Is this damage causing the problem?

I also took the opportunity to make the continuity checks described by leccy, and all seems well there (unlike my multimeter, but that's another story...)

Any suggestions etc gratefully received.

1980sjohn · 24 Nov 2009

Leccy758 said:
depending on the motor you could have a thermal fuse in the motor case

you should have 6 wires to the motor connection plug from the motor.

2 go to the brushes
2 go to the tacho 'thin wires'
2 go to the windings and go through a thermal fuse

if you have a multimeter check each pair, you should get a reading on Ohms. spin the motor armature when you do this and the resistance should change.

if the windings pair is open circuit I would assume thermal fuse blown

Hi,

I have a similar problem on my Bosch 1000 rpm machine (sorry don't have exact model to hand). I have checked the motor, and have an open circuit on two of the pins. I dismantled the motor (having nothing to lose!) and traced the connectors as follows:

2 go to the brushes (go through what is probably a thermal fuse unlike above)
2 go to the tacho 'thin wires'
2 go to the windings (no fuse found unlike above)

Connections to the windings are fine (around 10 to 20 ohm each).

The connections to the brushes are open circuit. I think it the circuit goes via a thermal fuse - it is a small rectangular block with a shiny case and two wires, shows open circuit.

Any ideas what temperature the fuse is?

The machine is about 6 or 7 years old, and is on its 4th set of brushes. The brush holders were white plastic with a brass tube, the plastic is very brown (over heating) and the brass very dark. Are the brush holders replaceable?

Before totally failing the machine had the same fault as others have, ie it will wash the clothes, but when it came to spin the water would drain, drum would go back and forwards slowly, but when a fast spin was attempted the timer would jump from 10 mins to 1 min and the cycle finish prematurely.

Regards,
John

poundfoolish · 24 Nov 2009

Had meant to update the thread with how I got on, 1980sjohn's post seems a good opportunity.

I didn't give up on my motor, which still wouldn't spin after a brush change, because:

1) did the continuity checks that Leccy758 suggested and they seemed to show things were OK.

2) read somewhere that electric motors that are really totalled almost always smell quite strongly of burnt insulation – and this one was fresh as a daisy

So the wife and I took the motor out and put it back 4 times, but we now know it could be done just once!. What we did was:

1) cleaned out the brush seats of as much old carbon as possible

2) made sure the brushes were well seated by gently filing till we had them moving really smoothly and easily yet without slopping about

3) made sure the brushes made good contact with the slotted bit (commutator?) on the spindle by wrapping a tube of similar diameter in sandpaper (finest I could find, which was coarser than I would have liked but seems to have worked OK) and gently rubbed the brushes til they were the same profile

4) gently rubbed the commutator(?), which was dirty and worn, with sandpaper till it was pretty bright.

Bingo, now spins up beautifully. Ta da.

(Having said that, if you put too big a load on it won't spin up, so presumably the motor has sustained some wear/damage and won't develop as much power as it once did. Still, it works finel on an ordinary load and it's a whole lot better than a new motor or new machine).

Hope that's of some help or at least encouragement ... good luck

jquirke · 24 Nov 2009

poundfoolish";p="1400040 said:
... but it won't spin properly.

As I said in my last post I checked the bushes again and found that one wasn't properly installed and wasn't making contact. A bit of delicate filing and it now seats properly and the motor runs again. So far so good, it washes BUT it won't spin. It's like it tries to spin but can't get going and reverts to agitation. Repeats twice, reverses, reverses again and gives up, the timer going from 10 minutes to 1 minute then 0. Have tried this half a dozen times.

The motor makes a different, sort of whining, noise. I presume this is because the brushes aren't bedded in and should improve? Will power and the ability to spin also improve.

The old bushes were very worn, and I notice there are marks where they contact the spindle. Is this damage causing the problem?

I also took the opportunity to make the continuity checks described by leccy, and all seems well there (unlike my multimeter, but that's another story...)

Any suggestions etc gratefully received.[I had the same problem, there was something stuck in the filter at the bottom of the machine. When I removed it everything started working file]

jquirke · 24 Nov 2009

jquirke";p="1418463 said:
poundfoolish said:

... ]

Click to expand...

I had the same problem. There were small coins stuck in the filter. Once they ere removed everything started working as normal

mplar · 8 Aug 2010

I recently replaced the brushes on the motor of my Exxcel 1200 express and this did the trick. 4 weeks on, though, and I am getting a burning rubber smell emanating from the back of the machine. If I'm not mistaken, the smell peaks during the water heating stage, and lessens during spinning.

I think my intervention to replace the brushes may have disturbed some connections on the heater element, which may be the cause of the problem.

Has anyone had a similar experience after replacing motor brushes? Could the smell be coming from the motor, maybe because the brushes are not well seated? Any ideas would be very much appreciated.

Thank you.

mplar

Leccy758 · 8 Aug 2010

Start by checking the connections on the motor and the heater are good and the connectors are not melting.
The motor brushes may not be seating correctly (did you clean out the brush holders as they are prone to a build up of carbon dust which prevent the brushes moving properly)
Is the drive belt rubbing anywhere

mplar · 8 Aug 2010

Hi Leccy,

Many thanks for your prompt reply.

I haven't gone ito the machine yet, as it's really difficult to remove from the built-in kitchen.

The smell is similar to melting insulation - so I'm discounting the possibility of a rubbing drivebelt.

The smell peaks in the middle of the cycle, and during spinning, when the motor is drawing full power, the smell is less.

Based on these symptoms, my feeling is that the wires to the heater element are melting due to poor contacts. The cotacts may be corroded, or perhaps loosened during my intervention a few weeks ago to change the brushes on the motor.

As per your question, the slots for the brushes were relatively clean - but I did not clean them, so cannot say for sure that there is no sediment preventing smooth movement of the brushes.

One thing I did notice was that one of the brushes was extremely tight when pushed more than half way down the slot. Looking into the slot, I noticed that there was a dimple/screw-head on one side, which created a groove on the brush when inserted. I immediately thought this was odd, but it looked like a design feature rather than a something that had arisen due to wear and tear. The brush was not freely-moving, and actually quite tight after inserting all the way to the bottom. The second brush was moving freely/smoothly. A stuck brush could be the cause of the problem, but then why is the melting smell highest when the current to the motor is at its lowest point in the washing cycle?

Leccy758 · 8 Aug 2010

When we fit new Bosch brushes even originals we quite often have to shave or paper them down so they fit properly and move smoothly.

A blown RF capacitor can cause a strong smell and sometimes they burn through as opposed to fail completely so the power does not go off (they can stink though as the plastic and electrolyte heats up).

Best to identify the cause though or risk a a major failure and attendant large cost.

mplar · 8 Aug 2010

Thanks for your reply Leccy,

Please could you let me know where the capacitor is located and whether it is part of the heater or the motor circuit.

Thanks,

mplar

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BOsch exxcel 1200 express

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