Uses & Design Differences An AC generator creates an alternating current that periodically reverses direction. But in a DC generator, a direct current flows in one direction. In an AC generator, the coil through which current flows is fixed and the magnet usually moves.

AC generators work on the principle of Faraday’s law of electromagnetic induction which states that electromotive force -EMF or voltage – is generated in a current-carrying conductor that cuts a uniform magnetic field.

Electric generators work on the principle of electromagnetic induction. A conductor coil (a copper coil tightly wound onto a metal core) is rotated rapidly between the poles of a horseshoe type magnet. When the coil rotates, it cuts the magnetic field which lies between the two poles of the magnet.

A stationary armature, rotating field generator has several advantages: (1) a load can be connected to the armature without moving contacts in the circuit; (2) it is much easier to insulate stator fields than rotating fields; and (3) much higher voltages and currents can be generated.

You can use just about any motor to generate electric current, if it is wired correctly and you follow specific rules for its use. Modern AC induction motors are quite simple to wire as alternating current generators, and most will begin generating electricity the first time you use them.

Induction generators operate by mechanically turning their rotors faster than synchronous speed. A regular AC induction motor usually can be used as a generator, without any internal modifications. An induction generator usually draws its excitation power from an electrical grid.

Reluctance and hysteresis motors cannot be generators because there is no `rotor` winding or permanent magnet on the rotor. I have a small 2400 watt generator that I use to power my home office when I lose power.

An electric motor is a machine that converts electrical energy to mechanical energy. An electric generator is a machine that converts mechanical energy to electrical energy. In a motor, current is supplied to the armature winding. In a generator, current is produced in the armature winding.