A magnetic holding relay is a special type of relay that has the ability to hold the magnetic field in a state of power failure. Magnetic holding relays usually consist of a control loop and a load loop.

Magnetic holding relays work as follows:

Control loop: When an external current passes through a coil in the control loop, a magnetic field is generated. This magnetic field magnetizes the relay's iron core and attracts movable contacts, causing it to close.

Load loop: When the contact is closed, the current can flow through the load loop. This means that the load (such as a motor, light bulb, etc.) is energized and starts working.

Magnetic holding characteristics: When the current in the control loop is cut off, the contacts remain closed because the magnetic field in the core remains present and keeps the contacts closed. This is because the magnetization of the core will hold even if the current in the control loop is cut off.

The magnetization and holding properties of magnetic holding relays make them very useful in many applications. It can be used in equipment that requires continuous operation for a long time, such as mechanical equipment that needs continuous operation or circuits that need to remain energized for a long time. In addition, magnetic holding relays can also be used in the control and protection of power systems, as well as logic control in automation systems.