Well, this turned out to be an interesting motor, at least, if you are a nerd like me 
Best as I can tell, it is likely 50 to 80 years old. After a little cleaning and wiring though, it still runs perfectly.
This is what is known as a replusion start motor. It has a wound rotor with the rotor windings terminating at a commutator. The brush sets are connected to each other and cause the rotor to develop magnetic poles which push against the magnetic field from the stator, and deliver a high starting torque on very little starting current. At about 3/4 of operating speed, a centrifugal mechanism at the front pushes the brushes away from the commentator and at the same time pushes a copper ring into contact with the inside of the commutator, shorting all the bars together. After that, the motor runs like normal squirrel cage induction motor. The brushes are no longer needed once the motor is running.
