Have this fan from a MicroWave Oven (MWO). Wiring it according to the top schematic results in the fan running at full speed. When wired the other way (bottom setup) the fan still runs, but runs on a much slower speed. The question is: Can this harm the motor or the cap?

 

Looks like I have two threads same subject. Moderators; please remove older thread. Thank you.

 

What is the reason for wiring the bottom method?
It will run the motor OK, just not very efficient.!
Compare the current between the two.
Max.

 

I've had the fan sitting on the shelf for some years. Had to figure out how to wire it. One way resulted in a weak flow, the other way a strong flow. I might want to use the lower method because I don't need the fan blowing like heck. But if I go with the lower schematic I wonder if I might hurt something. The motor or the starter cap possibly. So that's the reason for asking - to not damage equipment. The fan is currently sitting on the shelf awaiting connecting it up to something.

 

The cap should be OK, probably Motor run rated.
As I said, measure the current, but it should be low enough not to damage cap or Fan.
Max.

 

Thanks Max.

 

In the lower circuit the capacitor is in series with the opposite windin, which may have a different resistance value and a different resistance. and it may not be able to handle the power without getting a bit too warm. So you might have a heat -problem, either in the motor or in the capacitor.

 

Thanks @MisterBill2, I'll check that out.

 

@DickCappels Thanks for locking the other thread. Nobody responded to it anyway.