Magnetic retention relay advantages & disadvantages

- Jul 19, 2018 -

Magnetic retention relay advantages & disadvantages

The magnetic retention relay is a new type of relay developed in recent years and is also an automatic switch. Like other electromagnetic relays, it automatically turns the circuit on and off. The difference is that the normally closed or normally open state of the magnetic holding relay is completely dependent on the permanent magnet, and the switching of the switching state is accomplished by triggering a pulsed electrical signal of a certain width.

An appliance that turns the controlled output circuit on or off when the input amount (such as voltage, current, temperature, etc.) reaches a specified value. Can be divided into electrical quantities (such as current, voltage, frequency, power, etc.) relays and non-electrical (such as temperature, pressure, speed, etc.) relay two major categories. It has the advantages of fast action, stable operation, long service life and small volume. Widely used in power protection, automation, motion, remote control, measurement and communication devices. A relay is an electronic control device that has a control system (also called an input loop) and a controlled system (also called an output loop). It is usually used in an automatic control circuit. It actually uses a small current to control the larger. An "automatic switch" of current.

Magnetic retention relay structure

Divided into two layers, the upper layer is the electromagnetic system, the lower layer is the contact system, and the electromagnetic system uses a flat direct-acting magnetic retention magnetic circuit system, which includes a magnet, a coil, an armature, an iron core, a mounting plate, and a magnet is disposed in the center of the mounting plate, the magnet A coil is arranged on both sides, and a U-shaped iron core is arranged above the coil, and the armature is interposed between the iron cores to form a ring structure, and thus can be controlled by a magnetic field. The two ends of the mounting plate are located next to the U-shaped bottom of the iron core and are also equipped with a pure iron plate to prevent external magnetic field interference.

Principle characteristics of magnetic holding relay

Principle of action

The magnetic holding relay has its contact opening and closing state maintained by the magnetic force generated by the permanent magnet. When the contact of the relay needs to be opened or closed, only the positive (reverse) DC pulse voltage is needed to excite the coil, and the relay completes the state transition of the opening and closing in an instant. Usually, when the contact is in the holding state, the coil does not need to be continuously energized, and the magnetic force of the permanent magnet can maintain the state of the relay.


Action process

When the contact of the relay needs to be set, only the positive DC pulse voltage is needed to excite the coil J2. The magnetic pole generated after the excitation of the coil J2 interacts with the magnetic pole of the permanent magnet, the same polarity repels each other, and the opposite polarity attracts each other, so that the relay The state transition from reset to set is completed in an instant. Figure 1-4 illustrates the specific state transition process. The process of the magnetic holding relay being switched from the set state to the reset state is the same.

Advantages of magnetic retention relays

1, only need pulse excitation, can work in single or double coil

2, small size, PCB type installation

3, low power consumption, strong load capacity

4, safe and reliable, long life

Shortcomings of magnetic retention relays

The only disadvantage of the magnetic holding relay compared with the existing electromagnetic relay is that it consumes more material. In the long run, its environmental performance is better than that of ordinary electromagnetic relays. The seismic performance is not much different from ordinary relays.

Magnetic retention relay

1. Expand the scope of control

For example, when the multi-contact relay control signal reaches a certain value, it can switch, disconnect, and turn on multiple circuits at the same time according to different forms of the contact group.


2, zoom in

For example, sensitive relays, intermediate relays, etc., can control very high power circuits with a very small amount of control.

3, integrated signal

For example, when a plurality of control signals are input to a multi-winding relay in a prescribed form, the comparison is integrated to achieve a predetermined control effect.

4, automatic, remote control, monitoring

For example, a relay on an automated device, together with other appliances, can form a program control circuit for automated operation.