Electromagnetic Door Locks

The first electromagnetic lock was created in 1969 by Sumner "Irving" Saphirstein under request by the Montreal fire department for a safer and more reliable fire door lock. Sumner originally proposed a linear stack of door holders, but later dedicated his work to the creation of electromagnetic locks and security. Once his work was finished, electromagnetic locks became very common in office buildings and workspaces because of their simplicity and security. 

Electromagnetic door locks consist of an electromagnet and an armature plate. Generally, The frame of the door or gate will house the electromagnet because they are heavy, especially in cases where they are meant to be very secure. Generally, they are strong enough to withstand between 600lb or 1200lb of force. There are two different types, failsafe and fail-secure, keeping the door unlocked or locked respectively when power is lost. When power is sent to the electromagnet on the doorframe, the current running through the magnet will create a magnetic flux that bonds the magnet to the plate on the door.

Electromagnetic locks work well for situations where a reliable door is needed in cases such as emergency exit doors and fire escapes because they have no moving parts that could render it unusable in an emergency. It works by running a current through one or more loops of wire wrapped around a ferromagnetic core such as soft iron, creating a magnetic field that attracts the door to the frame when closed. The doors are especially secure because they are simple and withstand pressure very well due to current.