Automation Motor Reviews

DC electric motors are the inverse of the DC generator. They comprise armature field windings and commutator/brushgear and therefore 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 mixture of series- and shunt-wound). Each of these kinds of motor offers differing performance characteristics that could possibly be matched to the application which is why they are intended.

A specialized type of series motor may be the split-field motor where two groups of series windings of opposite polarity are each used in series while using armature but parallel with each other.

Either one group of field windings or another may receive power at any one time and for that reason the motor may run bi-directionally based on which winding is energized. When used in conjunction with suitable switches or relays this sort of motor is particularly useful for powering loads such as fuel system valves high might be a requirement to affect the position of various valves more than once during flight. Limit switches in the end with the actuator travel avoid the motor/actuator from overrunning after the desired position has been reached. Split-field motors are generally used for linear and rotary position actuators when found in conjunction with all the necessary position feedback control. DC motors are almost certainly to get used for linear and rotary aerospace actuators, fuel valve actuation and starter functions.

Aircraft AC motors

Aircraft AC motors are most commonly of the `induction motor' type. Induction motors operate upon the key which a rotating magnetic field is set up through the AC field current supplied to two or more stator windings (usually three-phase). A simple rotor, sometimes called a `squirrel cage', will rotate underneath the effects with this rotating magnetic field minus the requirement for brushgear or slip rings; the motor is therefore simple in construction and reliable. The speed of rotation of induction motors is dependent upon the frequency with the applied voltage and also the variety of pairs of poles used. The advantage in the induction motor for airborne uses is the simple fact that there exists always a way to obtain constant frequency AC power available and then for constant rated applications it provides an incredibly cost-effective solution. Single-phase induction motors also exist, nevertheless these require an additional set of phase windings to be switched in during the commencement phase, as single phase windings can merely sustain and not start synchronous running.

AC motors are most likely to get used for continuous operation, i.e. those applications where motors are continuously operating during flight, for example fuel booster pumps, flight instrument gyroscopes and air-conditioning cooling fans.