Stirrer motor

i have a GE microwave. it makes noise when turned on. I noticed if i unplug the stirrer motor the noise disappears. what is the stirrer motor used for?

Did you ever find the solution to your problem? I got the exact same problem. I unplugged the Stirring motor and the spark goes away. I plugged it back on and I can see the sparks between the motor casing and metal frame. I removed the Stirring motor and ordered a new one and I am hopping that this will eliminate the sparks.

Thanks