To turn the motor of a power generator, a process called electromagnetic induction takes place. Induction is the process wherein a conductor is placed inside a changing magnetic field. In doing so, it creates a voltage that is necessary to power up electrical items.
Many generators produce alternating current or AC to power up appliances. AC is an electrical current that cyclically varies in magnitude and direction, as opposed to direct current whose direction is always constant. This is the kind of power that is transmitted to homes and businesses.
There are three types of AC induction generators, three phase, two phase and single phase. A three phase induction generator has three conductors carrying voltage waveforms that are offset each other. A two phase induction generator is the same except that it has only two conductors. A single phase induction generator, as its name implies, has a single conductor. Let us focus on the last one.
Three phase-generators innately produce a rotating magnetic field. In the case of single phase induction generators, however, the rotating magnetic field must be produced by some other method since there is only one conductor which is not moving. The rotation of the magnetic field has to provided by some type of motor.
A common example of a motor that powers a single phase induction generator is a shaded pole motor. This is used to power up low torque devices such as electric fans and small household appliances. In this kind of motor, small single turn copper coils create the moving magnetic field.
Another kind of single phase induction generator motor is the split phase induction motor. This is commonly used in appliances such as washing machines and closed dryer. These motors can put up a greater starting torque using a centrifugal switch in conjunction with a start-up winding.
Another example of single phase induction generator motor is the capacitor start motor. In this case, a starting capacitor is inserted into in a series configuration with the start-up winding. This configuration creates an inducting circuit which has a greater phase shift. Like the split phase motor, it has a much stronger starting torque.
The last common type of motor in a single phase induction generator is the permanent slip capacitor motor. It operates much like a split phase induction motor. However, there is no centrifugal switch. The start-up winding is directly connected to a power source. These are used in fans, blowers and other utilities where the speed can be adjusted.
The technology of these motors ranges from simple to complex. Without them, we would never have any of the airconditioners, washing machines and electric fans that we use today.