Magnets or magnetic contactor switch is a switch that works by magnetism, meaning that the switch can work if there is a magnetic force. Magnet serves as towing and release contacts. A contactor must be able to drain and disconnect the electric current in normal circumstances. Electric current flowing normally is an electric current flowing during the termination does not occur. Magnetic coil contactor (coil) can be designed for direct current (DC) or alternating current (AC).
AC contactor on the core magnetic ring fitted short circuit to keep the flow of magnetism remain stable, so that the contactor is working normally. While the DC magnetic coils are not mounted ring short circuited. When the DC contactors are used in alternating voltage (AC), the magnetism will arise and disappear at any time following the voltage waveform alternating (AC). When contactors are designed for alternating voltage (AC) used in the direct voltage (DC), then at the coil will not cause induction so that the coil gets hot.
Conversely when the contactor for voltage (DC) which does not have a short circuit rings connected with alternating voltage (AC), the contactor will vibrate due to magnetization in the magnetic coils that arise and disappear every second 100 times.
Figure 5-1. Magnetic contactor.
Usually the contactors are several contacts, the normally open contact (normaly open / NO) and normally closed contacts (normaly close / NC). NO contact means when the contactor is not working position when the contactor opens and closes its contact position work / connect. So the function of NO and NC contacts an opponent. Contacts function consists of the main contacts and auxiliary contacts. Consists of the main contacts and auxiliary contacts NO contacts consist of NO and NC contacts.
Construction of different primary contact with auxiliary contacts, which have a main contact surface area that is large and thick. While the auxiliary contact surface area is small and thin.
Figure 5-2. The contacts on the contactor magnet.
The main contacts used to carry current in the primary circuit, the current required for electrical equipment for example: electric motors, aircraft pemenas and so on. Whereas the auxiliary contacts are used to control current flow in the circuit (control) required for magnetic coil, a series of tools, indicator lights, and so on. Category of use of the magnetic contactor as follows:
The use must be understood contactor control circuit (control) and power circuits (main). The controlling circuit is a circuit that simply describe the workings of the contactor with auxiliary contacts. While the primary circuit is a circuit that specializes in serving relationship with the source voltage electrical equipment (nets).