Why are permanent magnet household AC contactors widely used
The carrying current of the household AC contactor is very large. Generally, the internal pull-in coil controls its action or not, and the control coil is operated by various types of relays connected in series with it. It will trip after a thunderstorm because the relay of the household energy meter shunt AC contactor has an overcurrent or grounding protection function. When there is lightning on the line, it will control the action of the household AC contactor and cut off the load power to protect the equipment from high voltage. Large current damage or grounding may cause safety hazards.
Household AC contactors are widely used as electrical breaking and control circuits. The household AC contactor uses the main contact to open and close the circuit, and the auxiliary contact to execute the control command. The main contact generally only has a normally open contact, while the auxiliary contacts often have two pairs of contacts with normally open and normally closed functions. Small contactors are often used as intermediate relays to cooperate with the main circuit. So as to play the function of remote control or weak current control strong current.
The contacts of household AC contactors are made of silver-tungsten alloy, which has good conductivity and high temperature ablation resistance. Household AC contactors are divided into permanent magnet household AC contactors and electromagnetic household AC contactors.
The action power of the household AC contactor comes from an AC electromagnet. The electromagnet is composed of two "hill" shaped young silicon steel sheets, one of which is fixed, and a coil is placed on it. There are a variety of operating voltages to choose from. In order to stabilize the magnetic force, a short-circuit ring is added to the suction surface of the iron core. The household AC contactor relies on spring to reset after power failure. The other half is the movable iron core, the structure is the same as the fixed iron core, used to drive the opening and closing of the main contact and the auxiliary contact.
The permanent magnetic contactor is a new type of micro-power contactor formed by replacing the traditional electromagnetic drive mechanism with a permanent drive mechanism. The working principle is to use the principle of same-sex repulsion and opposite-sex attraction of magnetic poles. Because the polarity of the permanent magnet installed on the contactor linkage mechanism is fixed, and the soft iron fixed on the contactor base is under the action of external control signals, the electronic module solidified with it produces more than ten to twenty A few milliseconds of forward and reverse pulse currents make the soft iron produce different polarities, so that the main contact of the contactor can achieve the purpose of attracting, holding and releasing.