Need help with weird motor wiring of Vacuum Pump [SOLVED]

[AveragePhysicsEnjoyer]

Hello,

I am currently working on repairing a Leybold Trivac D10e Vacuum pump, but no matter what I try I cant figure out the motor wiring. When I got it someone already tempered with the wiring and the rotor was locked so I pulled everything apart figuring I will be able to wire it from scratch.
So the motor is a dual voltage motor, the motor must have been wired for both voltages at the same time, selectable by how you wire the connector.  It came with two 30uF Capacitors, which measure good. The coils of the motor seem to be tapped as I have drawn up in the schematic, I suspect a thermal switch between the gray and black wire.
I already tried some common configurations for these single phase motors, some of which included only one capacitor or two in series, but nothing just a small step opposite of the turning direction.

I haven’t found anything about induction motors with voltage selection on the internet and am not that familiar with the theory of operation of these motors that I can see what I am missing. Maybe some of you might know something or have an idea of what I can try to figure out the correct wiring.

[vindoline]

I would try reaching out to Leybold. They have been very helpful to me for repairing several older pumps I inherited in my lab.

[themadhippy]

I suspect a thermal switch between the gray and black wire

sure its not a centrifugal switch to switch the capacitor  once its got started

[BrokenYugo]

Those caps look huge to be the start cap for an easy starting ~1/2 hp motor, and I don't think the windings are symmetrical in a start cap motor. My guess would be it's a PSC motor.

[AveragePhysicsEnjoyer]

Currently waiting for Leybold to respond.
I did some research and am now sure its definitely a PSC motor,
I think there is one capacitor for each voltage range, for whatever reason they would do that.
I will post an update when I figured it out.

[Edison]

I suspect a thermal switch between the gray and black wire

sure its not a centrifugal switch to switch the capacitor  once its got started

If the motor had a centrifugal contact, the capacity of the capacitors would be different and the parameters of the auxiliary winding would be different. The running capacitor capacity would be about three times that of the starting capacitor, since both capacitors have the same value, the contact shown will be the thermal protection of the motor.

[IanB]

I watched this video recently, and thought it was a very good summary of how to analyze motor windings. I'll drop it here in case it might be helpful to you or others:

[Edison]

I watched this video recently, and thought it was a very good summary of how to analyze motor windings. I'll drop it here in case it might be helpful to you or others

Thanks for the link, but washing machine motors are a little different, the example shows a motor with centrifugal contact and a different winding (newer washing machine motors now have a speed sensor and the control is completely different). But it's nice to see what I wrote about, which is the difference in the winding.
Small thermal fuses in the winding cannot withstand a permanent load from the motor current and are intended to interrupt the motor control (in some motors they are replaced by a temperature sensor and this must not be connected to the winding at all)

[AveragePhysicsEnjoyer]

Damn, that's what I call good customer service.
They answered in less than 24h with a full wiring diagram of the motor,
I attached it bellow in case someone runs into the same trouble of rewiring such a weird motor.
The pump is over 20 years old, how awesome is it they still provide support for it?
I cant really say I understand how this motor is wired, but it works, so problem solved I guess.

[Edison]

I cant really say I understand how this motor is wired, but it works, so problem solved I guess.

The explanation of the principle of this connection is actually very simple - it is a classic motor connection with a main and auxiliary winding and one capacitor, but for the sake of easy switching of the operating voltage, both coils were divided in half, the auxiliary windings got their own capacitor and by changing the order (serial/parallel ) winding, the operating voltage is selected.

Thanks for sharing, we never know when it might come in handy.

[vindoline]

Damn, that's what I call good customer service.
They answered in less than 24h with a full wiring diagram of the motor.

Great news! They are great pumps.