Traction motor

A traction motor is an electric motor used to propel a vehicle, such as an electric locomotive, an electric multiple unit train, a trolleybus, a battery electric car or a vehicle with an electric transmission like a diesel-electric locomotive or hybrid car. The oldest type is the direct-current motor with series field windings, whose high torque at low speed suits accelerating a heavy vehicle, and whose speed can be varied by tapping the field winding. Alternating-current induction and synchronous designs are also used, the French TGV being one example of synchronous motors. The first experimental electric traction motor tramway appeared in 1875, and the technology was quickly adopted for city transport, where companies running motor-driven cars began to compete with horse-drawn railways.