The working principle and characteristics of electromagnetic

The working principle and characteristics of electromagnetic relay

Electromagnetic relays are generally composed of iron core, coil, armature and contact reed.As long as a certain voltage is applied to both ends of the coil, a certain current will flow through the coil, resulting in electromagnetic effect. The armature will overcome the pull of the returning spring and pull toward the core under the action of electromagnetic force, thus driving the moving contact of the armature to pull in the static contact (normally open contact).When the coil is cut off, the electromagnetic suction also disappears, and the armature returns to its original position in the reaction force of the spring to make the moving contact and the original static contact (normally closed contact) snap together.Such suction, release, thus achieved in the circuit conduction, cut off the purpose.As for the "normally open and normally closed" contacts of the relay, they can be distinguished in this way: the static contacts that are disconnected when the relay coil is not energized are called "normally open contacts";A static contact in the on state is called a normally closed contact.