Electronic – How to wire an old single phase AC brushed motor to be reversable

acmotorreverse-polarityuniversal-motor

I have searched several forums and found a lot of interesting stuff, but nothing yet that really applies to my situation. I have an old Westinghouse FH motor 1 1/2HP single phase brushed AC motor. There are four wires coming out of it. The wires are labeled T1, T2, T3, and T4. It is currently being used as a motor for a lathe. The T1 and T2 wires are joined together. And the T3 and T4 wires are joined together. I have the leads connected to a drum switch, but no matter what polarity is provided the Motor always spins one direction CCW. I don't see how reversing the polarity doesn't cause the direction to change. It doesn't appear to have a capacitor. I inherited the motor wired in this condition and have poked around on it a bit with swapping leads and other stuff but cant get it to run in any other configuration. Any knowledge is appreciated.

Wires
Motor Plate

Best Answer

Old Westinghouse Type FR motors were what is called an Induction / Repulsion motor, a very early type that is now no longer made because Capacitor Start motors are simpler and easier (and reversible). Yours probably dates back to the 1920s or 30s, maybe the 40s pre-WWII, but not younger than that. The brushes are used in acceleration only by creating repulsion with the stator windings, but are moved out of the way via a centrifugal mechanism as the motor speeds up. The video below shows the basic concept, albeit in an earlier form where the brushes were moved manually. https://www.youtube.com/watch?v=_KdaipeodLo

The thing about those motors was, they are not reversible. Sorry.