Bosch WFM3030GB/02 motor not rotating

[vinceofarrell]

Machine is 19 year old Bosch WFM3030GB/02. Drum not rotating or spinning under power but can be rotated by hand. Control knob rotates and makes usual noises. Machine fills and pumps out OK and belt looks fine. Motor removed – part number printed on side is 3047603AB5 – web suggests a standard Siemens motor but brush access looks different to that shown on usual Youtube videos – seems to use a U-section brass guide with rubber around guide, possibly with leaf rather than coil spring.

Checked resistance of pairs of contacts on the six contact socket. LH outer pair around 1.5 ohm varying as pulley rotated. Middle pair apparently open circuit continually as pulley rotated. RH outer pair around 15 ohm varying as pulley rotated.

Thoughts and suggestions welcome!

Does open circuit contact pair suggest motor windings failed?

If brush replacement indicated, how are they replaced? Does this motor require this replacement brush unit http://www.bosch-home.co.uk/store/product/Carbonbrush/496872 or is there a cheaper brush-only spare available?

TIA

Vince

[Martin]

Re: Bosch WFM3030GB/02 motor not rotating

The link you gave is the correct part and that will resolve the problem. You can bodge in a far cheaper alternative (though I wouldn’t recommend it) shown HERE

[vinceofarrell]

Re: Bosch WFM3030GB/02 motor not rotating

Thanks Martin for the link. I used that part – a pair of new brushes – and bodged a fix which is working well. The basic problem with this model of motor is that the brush housing is a large item not designed for brush replacement alone. Replacement brush units are a significant part of the complete motor assembly and cost over £50.

Small difficulties to be aware of when using this approach:
– ensuring the new brushes when fixed have long enough leads to reach, given that brushes are at their maximum (new) length. Need to cut off old brushes and new push-on tags to leave maximum lengths of braid to be connected.
– soldering the new copper braid leads to the old apparently steel braid leads. My iron being designed for modern electronic circuitry was not really powerful enough.
– ensuring the braid conductors are insulated – I used tape after realising the possible shorting risk – so that there is no risk of them shorting against the motor casing.
– making sure the conducting pins which mate with connectors on the motor body align properly before bolting the complete unit together again.

Thanks again for saving me over £40.

Vince O’Farrell

[Author]

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