powering a turntable AC21v engine from dismantled microwave

Lestraveled

Joined May 19, 2014
1,946
Why do you need any 21 volt turntable motors when you can get 120 volt and 240 volt turntable motors without making a special fan motor (with a 21 volt winding tap)? The fan motor and the big power transformer have to match the local power voltage. What's so hard about installing a turntable motor that uses the same voltage as everything else?

What? They only have to carry the 21 volt motors if they custom wind every fan motor for 120 volts and 240 volts?
I would think custom winding a fan motor costs more than stocking 2 voltages of turntable motor...or...they could use 240 volt fan motors with a center tap and only stock one fan motor and one turntable motor.

Here is a schematic for a Millermatic 150 Mig welder. Notice a part on the left labeled "FM". It stands for "Fan Motor". Also notice that it has a separate winding, it provides power to the wire speed control board. You don't have the expense of a transformer.

I think the 21 volt tap on the microwave oven fan fed more than the turntable motor. I bet it was rectified and powered the control board also.

 

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#12

Joined Nov 30, 2010
18,224
it has a separate winding, it provides power to the wire speed control board.
Well, now we have a reason to steal a voltage off a fan motor, but I still wouldn't have 21 volt gearmotors custom made when I can get gearmotors that run on the power line voltage.
 

Lestraveled

Joined May 19, 2014
1,946
@#12

There is something about that turntable motor. You can buy them anywhere. They are listed on Amazon. They are not customs, they appear to be a "standard" appliance part.

Maybe a 21 Vac motor is cheaper than a 120 Vac motor. I don't know.

People that design for mass production think differently than us. They have different rules.
 

ian field

Joined Oct 27, 2012
6,536
Why do you need any 21 volt turntable motors when you can get 120 volt and 240 volt turntable motors without making a special fan motor (with a 21 volt winding tap)? The fan motor and the big power transformer have to match the local power voltage. What's so hard about installing a turntable motor that uses the same voltage as everything else?

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Might be cheaper if you don't have to spot weld a pressed steel cover plate on the bottom of the case, because the wires are low voltage.

Often they're fixed on with self tapping screws - not a trivial assembly step.
 
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