An electromagnetic lock, or magnetic lock is a locking device that consists of 2 parts, electromagnet and armature plate.
Normally, the electromagnet part of the lock is installed to the door frame and armature plate is attached to the door.
The two components are in contact when the door is closed.
When the electromagnet is energized, a current passing through the electromagnet coil creates a magnetic flux that causes the armature plate is attracted
to the electromagnet, creating a locking action.
Because the coupling area of the electromagnet and the armature is relatively large,
the force created by the magnetic flux is strong enough to keep the door locked under tension.
There are different models of electro magnets, all depending on the retention force of the door, among the most popular is the 600 kg of retention, that is, you have to make a force of more than 600 kg to open the door.