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An '''electric motor''' is a device which converts electrical energy into kenetic and mechanical energy. Most electric motors utilise the [[motor effect]] in the collective deflection of a flow of electrons through a wire to turn a coil, however other models employ more ingenious devices such as the induction of [[eddy currents]].
An '''electric motor''' is a device which converts electrical energy into kinetic and mechanical energy. Most electric motors utilise the [[motor effect]] in the collective deflection of a flow of electrons through a wire to turn a coil, however other models employ more ingenious devices such as the induction of [[eddy currents]].
==Basic Motors==
==Basic Motors==
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 (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.
==DC Motor==
A DC electric motor converts a DC input current into kinetic energy. It uses a split ring commutator to ensure the current in the coil is maintained in the same direction as the stator field (and hence keep the coil turning in the same direction). A split ring commutator is a ring of conductive material around a cylinder base with two slits on either side of the ring, positioned such that the [[chord]] between the two splits is perpendicular to the brushes when the coil is perpendicular to the stator field, meaning that the direction of the current will be reversed in the coil (although kept constant with respect to the stator field) when the coil is deflected to its maxima, allowing the motor to keep turning.
==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 50Hz 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.
==See Also==
==See Also==