Types of Magnetic System

 Types of Magnetic System

• In a magnetic system, a coil is wound over a magnetic material. By exciting this coil with a suitable electrical source, the energy can be stored or retrieved from a magnetic system. Depending on the number of excitations used, the magnetic systems are classified as,          

1. Single excited systems.

2. Multiple excited systems.

• In singly excited system, a single exciting coil is used to produce the magnetic field. The various examples of such a system are, electromagnetic relay, reluctance motor, toroid coil, hysteresis motor, solenoid coil etc. The Fig. 2.5.1 shows attracted armature type relays which is an example of single excited system.

•  In special devices more than one excitation coils are necessary. Such systems are called multiple excited systems. Very commonly used multiple excited systems use two excitation coils and are called doubly excited systems. The examples are synchronous motors, alternators, d.c. shunt machines, loudspeakers etc. in which separate excitation coils are provided on stator and rotor.

The Fig. 2.5.2 shows one such type of doubly excited magnetic system. Let us study the details of these two types of magnetic systems.

Review Question

 1. State the types of magnetic systems alongwith two examples of each.