The principle of electromagnetic door lock is also magnetic lock. The design of magnetic lock (also known as Electromagnetic Lock) is similar to that of electromagnet, which uses the principle of electrogenerated magnetism. When the current passes through the silicon steel sheet, the electromagnetic lock will generate strong suction force to tightly attract the adsorption iron plate and achieve the effect of locking the door. As long as a small current is applied to the electromagnetic lock, it will generate tremendous magnetic force. The access control system that controls the power supply of the electromagnetic lock will identify the correct personnel and then cut off the power. The electromagnetic lock will lose its suction force and open the door. Because electromagnetic locks do not have complex mechanical structures or lock tongue structures, they are suitable for controlling access to escape doors or fire doors. It is protected by injecting epoxy resin inside the lock body.