In article ,
Brian Reay writes:
On 13/03/2018 12:26, The Natural Philosopher wrote:
On 13/03/18 11:39, Brian Reay wrote:
On 12/03/18 11:39, Andy Burns wrote:
Andy Burns wrote:

That said I expect to be able to get at the turntable motor/gearbox
without going near the "active" end ... any other gotchas?

Oh, and how universal are the "so called" universal motors?


They tend to be the larger motors sometimes used in washing machines.
The motors used to drive turn tables in uwaves (and water pumps in
washing machines and dishwashers) are small, AC, motors.

I dont think so for washing machines and dishwasher. Fairly sure the
ones I have taken out were brushed.


Universal motors of the type I'm describing have brushes.

I don't recall seeing one in a dishwasher but I've not looked at many so
that isn't conclusive.

Main wash pump motors that I've seen in dishwashers are all
2-phase with a run capacitor.

The waste pumps in dishwashers and washing machines are all
shaded pole motors.

Drum motors in washing machines are universal motors (i.e.
with brushes) when belt driven, and stepper motors (brushless)
when direct drive. Drum motors need good starting torque and a
very wide speed range, which the other motors above don't have.

I can still recall my parents' first washing machine, which
predated any sort of electronic motor control. I'm not sure
what the motor was, but it was single speed, single direction.
It had a sodding great gearbox attached with a handful of large
solenoids around it to do the gear changes. I can still clearly
recall the loud bangs as the different solenoids engaged to
change the drum speed throughout the program. When it was
scrapped, I saved the mains solenoids and some other parts,
which got used in a few projects afterwards. They did tend to
overheat, as the washing machine was for 200V mains, and had
been converted to 240V when the mains voltage changed by
fitting a large autotransformer inside the case, which I
hadn't kept because it was too heavy.

--
Andrew Gabriel
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