Magnetic holding relay

- Jul 12, 2018-


The relay is an automatic switching element with isolation function. It is widely used in remote control, telemetry, communication, automatic control, mechatronics and power electronics. It is one of the most important control components.

Relays generally have an inductive mechanism (input section) that reflects certain input variables (such as current, voltage, power, impedance, frequency, temperature, pressure, speed, light, etc.); it has the ability to "pass" and "control" the controlled circuit. The actuator (output portion) of the control unit is disconnected; between the input portion and the output portion of the relay, there is also an intermediate mechanism (drive portion) that couples the input amount, functions, and drives the output portion.

Relays have the following effects:

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.

The factory specializes in producing all kinds of time relays, electromagnetic relays, electronic relays, high-power relays, liquid level relays, solid state relays, high-power relay small relays, timers, counters, relays, etc.


The relay is essentially an electrical device that transmits signals, which achieves different control purposes depending on the input signal.

The relay is generally used to turn the control device (motor) on and off.

For example, in a current relay in a DC motor, when the current is too small or too large, it detects the current signal and then controls the start and stop of the motor.

Also, if a thermal relay, such as a motor that is overloaded for a long period of time, causes the temperature to be too high, it controls the motor to stop.


1. First understand the necessary conditions

1 control circuit power supply voltage, the maximum current that can be provided;

2 voltage and current in the circuit being controlled;

3 The controlled circuit needs several sets and what forms of contacts. When a relay is selected, the power supply voltage of the general control circuit can be used as the basis for selection. The control circuit should be able to provide sufficient operating current to the relay, otherwise the relay pull-in is unstable.

2. After consulting the relevant data to determine the conditions of use, you can find the relevant information and find the model and specification number of the required relay. If there is a relay on hand, you can check whether it can be used according to the data. Finally consider whether the size is appropriate.

3. Pay attention to the volume of the appliance. If it is used for general electrical appliances, in addition to considering the chassis volume, small relays mainly consider the layout of the circuit board. For small appliances, such as toys and remote controls, ultra-small relay products should be used.