Electromagnetic Lock Basics

 Electromagnetic locks are designed to provide security for doors or gates that close on a solid frame or block. electromagnetic locks are fail-safe locking mechanisms that require constant power to remain locked. They are intended to provide basic flow control with up to medium security levels.

 

Basic electromagnetic locks are typically mounted on the door frame of an exterior swing door. A black metal armature plate is mounted on the face of the door, aligned with the joint of the electromagnet. When the door is closed and the electromagnet is energized, the current flowing through the coil generates a magnetic field. This magnetic field attracts the armature plate mounted on the door. The armature is pulled against the electromagnet with sufficient force to prevent the armature (door) from being opened.

 

A electromagnet is a piece of metal that is wrapped in wire and then energized. In its basic form, a electromagnetic lock is a locking device with no moving parts, relying on the magnetic field generated to lock the armature (impact) to the magnet. To energize the magnet, a coil (coils) is wrapped around the metal and a circuit is used to control the direct current (DC). Most electromagnetic locks have a very small current draw and cost far less to operate than conventional light bulbs.

Waterproof Electromagnetic Lock

The electromagnet component consists of a metal alloy formed into a specific shape. The goal is to produce the largest possible magnetic field within a limited size housing. The exact chemical composition of the alloy varies from lock manufacturer to lock manufacturer and is a closely guarded secret. The reason for this is that the molecular structures of the specific metals align with each other, thereby greatly increasing the magnetic flux density (armature holding power).

 

The shape of the electromagnet is usually a rectangle with a flat surface to maximize the electron bonding capability of the armature. Early mounting options were head-mounted and face-mounted. Head mount implies vertically extending holes in the side of the magnet housing. Face mounts were horizontal holes. Over the years, lock manufacturers have developed a variety of mounting options for magnet locks using specially designed brackets and spacers. For example, a top door frame mounting kit would be suitable for flush door applications.

 

Mounting and installation modifications include the addition of a splice chamber and ladder mounting bracket and slot mounting in the lock housing. The fusion chamber has been incorporated into the housing of some magnetic locks. The fusion chamber typically contains circuit boards with sufficient area to connect wires.

 

When installing a "block" magnetic lock that contains existing mounting holes positioned vertically or horizontally, the installer must hold the magnet in place and activate several mounting bolts to hold the magnet in place.

 

The trapezoidal mounting bracket was developed to allow the bracket to be installed into the header tube first. The electromagnetic lock is then slid into place and it is determined what final adjustments need to be made. Several of the mounting holes in the trapezoidal mounting bracket are elongated, allowing for back and forth adjustment to position the magnet for maximum attraction. Once in place, tighten the existing set screws to secure the magnetic lock in place.