Brush type ac motor. There are at least three types of ac motors that use brushes on the armature synchronous wound rotor induction motor for low speedtorque control used on cranes etc and universal acdc series connected motor i would say you have the latter if it is on a band saw. A brushed dc electric motor is an internally commutated electric motor designed to be run from a direct current power source. The addition of a compensating winding yields the compensated series motor overcoming excessive commutator sparking. So why choose one technology over the other.
There are several key differences between the different technologies. Oriental motor manufacturers a wide range of ac motor and brushless dc bldc gear motor products. If you have seen sparks through the motor cooling vents on a power drill you have seen electric motor brushes at work. Typical applications include electric motors alternators and electric generators.
The resulting motor is only practical in the smallest sizes. Brushless dc motors provide high power in a small package. Brushed motors were the first commercially important application of electric power to driving mechanical energy and dc distribution systems were used for more than 100 years to operate motors in commercial and industrial buildings.