I took apart this Corning pc-420 hotplate stirrer without recording which wire goes where. Unfortunately there's no schematics online for these models. How do i figure out which wire of this motor is positive and negative?

 

Motors dont really have positive and negative input, they can rotate CW or CCW depending on the voltage... so the worst thing that can happen is your motor to rotate in opposite direction..

 

I took apart this Corning pc-420 hotplate stirrer without recording which wire goes where. Unfortunately there's no schematics online for these models. How do i figure out which wire of this motor is positive and negative?

View attachment 343931

Neither.
It's an AC motor. Looks like a shaded pole motor to me but @MaxHeadRoom will confirm, in which case it will have a fixed direction of rotation depending on the position of the shading rings.

 

If the motor is AC that is correct.
Probably that is why it doesnt have different colors on the wires.

 

Neither.
It's an AC motor. Looks like a shaded pole motor to me but @MaxHeadRoom will confirm, in which case it will have a fixed direction of rotation depending on the position of the shading rings.

It is a Shaded 2 Pole motor. We can see the Shading Coils in the photo.

 

It is a Shaded 2 Pole motor. We can see the Shading Coils in the photo.

That's it. It will always spin in one direction regardless of which of the two black wires go where. The green wire is just a ground.

 

Neither.
It's an AC motor. Looks like a shaded pole motor to me but @MaxHeadRoom will confirm, in which case it will have a fixed direction of rotation depending on the position of the shading rings.

Yup, shaded pole, you can see the two shorted turns.
Cheap form of AC motor, but not too efficient!
The only way to reverse it is to swap the armature end for end.

 

The only way to reverse it is to swap the armature end for end.

I've actually done that. Back when I was in High School. Had a fan that ran the wrong way (wrong spin direction). Unbolted the armature and swapped it around. I was so proud of myself.

 

This is the shade pole coil, (dead center of the picture) that copper thing. Don't ask me how it works.

 

The motor shade-pole is an inefficient way to generate a second phase of EM field energy from a single phase supply. That second phase provides the rotational vector to start the shaft spinning.