A motor is a device, which converts electrical energy into mechanical energy. The modern power station requires a wide range of electric motors ranging from small fractional power to motors as large as 15 MW. There are about 2,000 motors in a typical power station.
2.0 PRINCIPLES OF ELECTRIC MOTORS OPERATION
One of the most frequently used effects of electric current is its ability to produce force called magnetism. This force is responsible for the operation of motors, generators, measuring instruments, and communication equipment, transformers and control devices.
Iron, nickel, and some oxides and alloys are called magnetic materials because they can be magnetized. A rough classification divides magnets into two groups; permanent and temporary magnets.
A permanent magnet will keep its strength after the magnetizing force is removed. Many alloys make excellent permanent magnets as well as high carbon steels.
Temporary magnets become strongly magnetized when placed inside current carrying coil. These electromagnets have a much wider use and a greater variety of applications than permanent magnets. The material used most frequently for electromagnets is the soft alloy silicon iron. This alloy is used in transformers, motors, and generators, relays, and other electromagnetic equipment.