What is a magnetic latching relay

Update:02-12-2021
Magnetic latching relay is a new type of magnetic latching relay developed in recent years. It is also an automatic switch. Like other electromagnetic relays, it can automatically switch on and off the circuit. The difference is that the normally closed or normally open state of the magnetic latching relay completely depends on the action of the permanent magnet, and the switching state of the magnetic latching relay is triggered by a pulsed electrical signal of a certain width. Magnetic latching relays are divided into single-phase and three-phase. According to relevant information, the maximum contact switching current of magnetic latching relays on the market can reach 150A; the control coil voltage is divided into dc9v and the general electrical life is 10,000 times; the mechanical life is 1 million times; the contact voltage drop is less than 100mV.

Therefore, it has the characteristics of power saving, stable performance, small size, large carrying capacity, and better performance than ordinary electromagnetic relays. Magnetic latching relays are mainly used for IC card prepaid electricity meters and centralized meter reading systems. In recent years, magnetic latching relays have been widely used in composite switches of reactive power compensation devices. Combined with the thyristor, it becomes the main switching device in the reactive power compensation device for switching large current circuits. It can also be used in various household appliances and automatic control devices (such as lighting control systems.

The magnetic latching relay is divided into two layers, the upper layer is the electromagnetic system, and the lower layer is the contact system. The electromagnetic system uses a flat direct-acting magnetic circuit system, including magnets, coils, armatures, iron cores and mounting plates. The magnet is located in the center of the mounting plate, and coils are installed on both sides of the magnet. A U-shaped iron core is arranged above the coil, and the armature forms a ring structure in the iron core, which can be controlled by a magnetic field. The two ends of the mounting plate are located beside the U-shaped bottom of the iron core, and a pure iron plate is also installed to prevent interference from external magnetic fields.

The open/closed state of the magnetic latching relay is usually maintained by the magnetic force generated by the permanent magnet. When the relay's contacts need to be opened or closed (that is, when the load is switched on or off), the relay can be excited by a positive (negative) DC pulse voltage to instantly complete the open and closed state switching coil. The power loss is generally less than 1W. Usually, when the contact is in the holding state, the coil does not need to continue to be energized, and the state of the relay can be maintained only by the magnetic force of the permanent magnet steel. Relay is an automatic switching element with isolation function, which is widely used in remote control, telemetry, communication, automatic control, mechatronics and power electronic equipment, and is one of the most important control elements.