Working Principle of Alternating-Current Generator

by Starlight Generator dieselgeneratortech

There are many forms of generator, but the working principle is based on the law of electromagnetic induction and the law of electromagnetic force. Therefore, the general principle of its construction is to use appropriate magnetic conductive and conductive materials to form magnetic circuits and circuits for mutual electromagnetic induction to generate electromagnetic power and achieve the purpose of energy conversion.

Working principle of alternating-current generator

The mechanical energy of the prime mover is converted into electrical energy output by using the principle of electromagnetic induction in which the cutting of magnetic lines of force by a wire induces electric potential. A synchronous generator consists of a stator and a rotor.

The stator is the armature that emits power, and the rotor is the magnetic pole. The stator is composed of armature iron core, three-phase winding with uniform discharge, base and end cover. The rotor is usually a hidden pole type, which is composed of excitation winding, iron core and shaft, guard ring, center ring and so on. A direct current flows into the rotor's excitation winding to generate a nearly sinusoidal distributed magnetic field (called the rotor field), and its effective excitation flux intersects the stationary armature winding. When the rotor rotates, the rotor's magnetic field rotates with it. With each revolution, and the magnetic field lines sequentially cut each phase winding of the stator, and the three-phase AC potential is induced in the three-phase stator winding. When the generator is running with a symmetrical load, the three-phase armature current is combined to produce a rotating magnetic field with synchronous speed. The stator magnetic field interacts with the rotor magnetic field to generate braking torque.

Alternating-current generator/alternator is divided into single-phase generator and three-phase generator. Alternator is often used in diesel generator sets.