Electric motors that nowadays are used to propel electric and hybrid vehicles got some characteristics differing from industrial electric motors. Motors used in vehicles need to satisfy many conditions. Frequent starts and stops, high ratio of acceleration and deceleration, low torque on high speed movement, high torque on low speed climbing. The electric motor propelling electric and hybrid vehicles can be sort into 2 groups:

commutator motors

commutatorless motors

Commutator motors usually represent traditional DC motors. They can provide great deal of adjustable speed, frequent starting, stopping and reversing. Principle in DC motors operation is straightforward and it consists of field system (stationary) and armature commutation system (rotating).

The performance of DC motors, practically can be expressed by the armature voltage, field flux and electromotive force.

Typically, there are four types of wound-field DC motors, depending on the mutual interconnection between the field and armature windings. They are separately excited, shunt excited, series excited, and compound excited.