Electric Motors Are The Inverse of The Electric Generator

Electric motors are the inverse of the Electric generator. They comprise armature field windings and commutator/brushgear and are similarly self excited. The main elements of importance in relation to motors are the speed and torque characteristics, i. E. The variations of speed and torque with load respectively. Motors are categorised by their field winding configuration (as for generators) and typical examples are series-wound electric motors, shunt-wound electric motors and compound-wound (a combination of series- and shunt-wound). Each of these types of motor offers differing performance characteristics that may be matched to the application for which they are intended. A specialized form of series motor is the split-field electric motor where two sets of series windings of opposite polarity are each used in series with the armature but parallel with each other. Either one set of field windings or the other may receive power at any one time and therefore the motor may run bi-directionally depending upon which winding is energized. When used in conjunction with suitable switches or relays this type of motor is particularly useful for powering loads such as fuel system valves where there may be a requirement to change the position of various valves several times during flight. Limit switches at the end of the actuator travel prevent the motor/actuator from overrunning once the desired position has been reached. Split-field motors are commonly used for linear and rotary position actuators when used in conjunction with the necessary position feedback control. Electric motors are most likely to be used for linear and rotary aerospace actuators, fuel valve actuation and starter functions. Source: speedreducer.org