Electric Motor DeRotator

I know some of you are asking “what does it do” ? I would assume it is used for decelerating an electric motor. The paperwork I have on it says that it originally cost $50,000, but I am expecting to get a bit less !
The unit offered appears to be in good physical condition. The only damage seen on the unit is that the left dial adjustable potentiometer is missing its cover and right dial adjustable potentiometer has been broken. The cover is still with the right one, so it should be able to be put on the left. Due to my lack of experience with these, I have no way to further test this unit, therefore it is being sold "as is".