Fixed the microwave turntable.

[ss]

I got a new `motor` for the turntable £5 on ebay and that sorted the non turning turntable. Out of interest I dismantled the `not working` one and it appears that when in use liquid has been allowed to spill out and leak through the the spindle to the motor. As far as I can see I just need to clean up the cogs of all the sticky stuff that has accumulated on them. From the image one part has wiring, is there any way to check if this is ok as in not broken as I intend to put it back together to see if it still works. I have a multi meter but dont know how to use it for this part. (continuity?)

[T i m]

Cool.

Good man. ;-)

Given the spindle sits under the turntable and can't normally be accessed directly, that could either be from something boiling over and running under the turntable or over zealous cleaning and liquids?

I can't see the picture here for some reason (I just get a black screen in Chrome or FF but this is an old XP box) but you might first need a solvent for the spilled stuff (hot soapy water?) and then a soak in say paraffin followed by good dry out and re-lube of any bearings or re-grease any gears etc?

Yes, you are looking for ohms across the motor coil. Might be around

100 ohms but that's just a bit of a guess.

If it's short circuit (0 ohms) or infinity then it's faulty.

Cheers, T i m

[Fredxx]

Set meter to resistance, say 20k and measure. I suspect/guess you should see 2k or so. If the meter doesn't show a change when connected to the winding then it's probably open circuit.

To be honest the pic looks a mess and not obvious its going to clean up!

[Paul]

TURNTABLE MOTOR 1. Remove wire leads 2. Measure resistance. Normal: Approximately (ohm meter scale: Rx1000) 2.0 to 3.0 Kohms

But that's a 120V microwave service manual, and a microwave with a higher mains voltage will likely use a different motor.

Google search term: "microwave motor ohms"

rather than just search for a manual.

I was hoping to see some values for the HV cap, but no such luck.

Paul

[Brian Gaff (Sofa]

These motors seldom die though, unless something has corroded where wires join or the actual coating on the coil has been attacked by something, but if it went short I'd expect there to be evidence, like a blown fuse or charred and melted components. Brian

[ss]

Yes it is a mess but if the wiring checks out ok I can clean the rest up that wont be a problem.

[ss]

Ok zilch reading from the multi meter, on closer inspection I can se some broken wires so thats that little exercise finished and heading to the bin.

[alan_m]

Are you sure that its not the grease applied during manufacture?

Video of some American who hasn't got a clue why he got a shock from a microwave turntable motor when driving the spindle with an electric drill. His dismantling of the motor does show grease around the gears.

So to see if the motor is OK attach a drill to the shaft that drives the turntable, put your tongue across the two terminals and turn on the drill at the highest speed. If you feel a slight tingle on your tongue the motor is likely to be OK.

[Andrew]

I think mine has though.

I forced back the knurled metal 'clips' that held the gearbox casing together and the gears were fine, plenty of grease. I tried connecting the motor to the mains and nothing happened, not even a buzzing. Resistance across the power tags a couple of mega-ohms.

Andrew

[Paul]

When it comes to enamel wire and magnetics, the place where the wire solders to any post, is a weak spot. On coils at work, that's where I was seeing failures.

Failures elsewhere are still possible. Poor quality wire, aluminium wire! and so on. They sometimes wind motors with Al rather than Cu to save a buck. Some pumps use Al.

Also, be aware there are two kinds of motors. AC Mains motors, and 21VDC motors. Don't connect the wrong kind right to mains. If the label on the motor admits to mains AC and is not a DC motor, then go right ahead.

*Never* connect stuff to mains, without some evidence it's the right thing to do :-) It makes Thor the god of electricity angry when you do that. Thor will send the magic smoke.

Paul