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==Basic Motor Design==
==Basic Motor Design==
A basic motor consists of a coil placed in a magnetic field. As current passes through the coil it will experience a force such that one side of the coil will be deflected upwards and the other side downwards (as the current is running in opposite directions), resulting in the coil turning. When the coil turns such that is is parallel to the magnetic field (and hence no force of deflection) the direction of the current is reversed, both sides of the coil will now experience a force in the opposite direction, resulting in the coil continuing to turn. As the current is reversed every 180<sup>O</sup> turn of the coil it will continue to turn provided there is a power input.
A basic motor consists of a coil placed in a magnetic field. As current passes through the coil it will experience a force such that one side of the coil will be deflected upwards and the other side downwards (as the current is running in opposite directions), resulting in the coil turning. When the coil turns such that is parallel to the magnetic field (and hence no force of deflection) the direction of the current is reversed, both sides of the coil will now experience a force in the opposite direction, resulting in the coil continuing to turn. As the current is reversed every 180<sup>O</sup> turn of the coil it will continue to turn provided there is a power input.
The basic motor, whether DC or AC, consists of the following components:
The basic motor, whether DC or AC, consists of the following components:
The force on either side of the coil is given by ''F = nBIlsinX'' where n = number of coils, B = magnetic field density (tesla), I = current (amps), l = length of the wire (meters) and X is the angle of rotation of the coil (0<sup>O</sup> when the coil is parallel to the stator field, 90<sup>O</sup> when it is perpendicular to the field. This may seem contradictory, as in the motor effect a charged particle travelling parallel to a field will experience no force. However, the force on the coil is along the sides which are always perpendicular to the stator field, and hence will always experience a force, the reason the coil doesn't turn any further when it is at 90<sup>O</sup> is because it has been deflected as far as it can go, and needs to have the current in the coil reversed to keep turning.
The force on either side of the coil is given by ''F = nBIlsinX'' where n = number of coils, B = magnetic field density (tesla), I = current (amps), l = length of the wire (meters) and X is the angle of rotation of the coil (0<sup>O</sup> when the coil is parallel to the stator field, 90<sup>O</sup> when it is perpendicular to the field. This may seem contradictory, as in the motor effect a charged particle travelling parallel to a field will experience no force. However, the force on the coil is along the sides which are always perpendicular to the stator field, and hence will always experience a force, the reason the coil doesn't turn any further when it is at 90<sup>O</sup> is because it has been deflected as far as it can go, and needs to have the current in the coil reversed to keep turning.
Torque is defined as the turning effect of the force, in this scenario it is the ability of the motor to do work (eg turn another object). ''Torque = Fs'' where s is the distance of the application of the force to the turning point (in this case the side of the coil to the axle). However, as there are two sides to consider the value of s is the length of the coil not affected by the field, hence allowing the derrivation of ''Torque = BIAcosX'' where A is the area of the coil. A motor with high torque will be able to exert a larger force on another object, in contrast a motor with low torque may not be able to carry much of a load. Torque is not related to speed, a motor can have a high turning speed and low torque, and vice versa.
Torque is defined as the turning effect of the force, in this scenario it is the ability of the motor to do work (e.g. turn another object). ''Torque = Fs'' where s is the distance of the application of the force to the turning point (in this case the side of the coil to the axle). However, as there are two sides to consider the value of s is the length of the coil not affected by the field, hence allowing the derrivation of ''Torque = BIAcosX'' where A is the area of the coil. A motor with high torque will be able to exert a larger force on another object, in contrast a motor with low torque may not be able to carry much of a load. Torque is not related to speed, a motor can have a high turning speed and low torque, and vice versa.
==DC Motor==
==DC Motor==
==AC Synchronous Motor==
==AC Synchronous Motor==
An AC synchronous motor uses a slip ring commutator instead of a split ring commutator, in which a fixed circuit feeds power to the coil. The current is reversed in the coil as the current from the power source reverses direction. However, in order to keep the current in the coil travelling in the same direction with respect to the stator field (and hence keep the coil turning in the same direction) the motor needs to turn at the same frequency as the frequency of the current (eg in countries where alternating current operates at 50 Hz the motor would have to turn exactly 50 times per second, or at 3000 rpm). Although this is a major drawback of AC synchronous motors it can be overcome using gears to allow larger objects to turn at a lesser speed.
An AC synchronous motor uses a slip ring commutator instead of a split ring commutator, in which a fixed circuit feeds power to the coil. The current is reversed in the coil as the current from the power source reverses direction. However, in order to keep the current in the coil travelling in the same direction with respect to the stator field (and hence keep the coil turning in the same direction) the motor needs to turn at the same frequency as the frequency of the current (e.g. in countries where alternating current operates at 50 Hz the motor would have to turn exactly 50 times per second, or at 3000 rpm). Although this is a major drawback of AC synchronous motors it can be overcome using gears to allow larger objects to turn at a lesser speed.
==AC Induction Motor==
==AC Induction Motor==