Hoover washing machine drain pump

Hose throbbing is caused by the remaining body of water oscillating up & down the pipe, into and out of the pump. Once it starts throbbing the machine has emptied. Unfortunately this thread will now get lots of google hits.

NT

Virtually all w/m pump motors are ac shaded pole types. no permanent magnets in sight. Generic replacements are cheap and usually easy to fit. Check that the impeller is firmly fixed to the motor shaft and no hair wound round the shaft. Noting else to go wrong really.

Shaded pole motor - non-synchronous low efficiency induction motor. The armature is a lump of iron (laminated for efficiency) with a squirrel cage of copper wire around it to form one-turn coils, and the stator induces a matching AC magnetic field into it.

It doesn't sound like there's anything wrong with it, but you haven't actually said what is wrong.

I had (I think it was) a CH pump which stopped working because all the fins had corroded off the impeller. But WM/DW pumps usually have plastic impellers of course.

That's actually quite common. Caused by cavitation rather than corrosion (and probably use of cheap alloys).

and don't run for anywhere near as long.

The pump motor runs when removed from the washing machine and connected to the mains by itself. The bearings appear OK. What I can't tell is whether it delivers full power.

The washing machine does not empty itself properly. The water level sensor pipe is not blocked. So maybe the fault lies with the programmer or the sensor.

I'd bet on the hose/drain slowing down emptying too much

NT

Shaded pole motors either work or they don't. In which case they'll be open circuit, or heat up like crazy.

Leave it running for 10 minutes or so and if it's still ok, ie no smoke, then the motor is fine.

Are the blades intact and run with only a small clearance to the housing.

If all the above is fine I would start blaming blocked pipework or something else.

Hmm, I'm pretty sure I've had one that just became feeble. It spun, but with much reduced torque.

I could be wrong however. It's not like they have a lot to go wrong with them.

Tim

Tight bearings / seals from carbonate will steal torque.

It spun freely enough by hand...

Tim

I eventually decided to remove the armature. This is what it looks like after I had cleaned it, removing both crud and water. I suspect the seal on the shaft it failing.

That looks like my pond pump. They definitely DO lose power/torque/strength over time. Just replace it.

Tim

The small drain pumps don't normally have a shaft seal - the whole armature runs in the water (and relies on the water to lubricate it). I can't see enough detail on yours to tell if it is meant to work like that.

The main wash pump (much larger) normally has an axial shaft seal, and failure of that, resulting in dishwasher water running into the motor bearings, often writes off that motor and the dishwasher.

I've seen ones that run but run very hot, ones that jam/stall etc

NT

The rotor does not look quite right for a standard shaded pole motor. Looks more like a lump of ferrite and so could be a permanent magnet. The plastic moulding and absence of an obvious squirrel cage bars suggests to me it could be a total immersion type rotor with the driving coil magnetically coupled through a thin plastic cylinder to form the water seal and yes very like small pond/water feature pumps.

I'd just replace it with a pattern part - ebay etc if you can wait for it to arrive or pay through the nose over the counter.