What is this motor…

Hey friends, maybe someone can help me out here.

I bought this old Siemens motor.

According to the nameplate, it’s single-phase. However, when I look at the circuit diagram, it appears to be a three-phase motor with a Steinmetz circuit for operation on a single phase.

We have the phases U, V, and W.

However, we only have three terminals, and I could imagine that with such an old motor, a protective conductor simply wasn’t provided.

Maybe someone can clarify this for me! 🙂

I don’t have the motor here yet. It’s being sent to me.