About electromagnetic locks for doors and gates
Maglock or the electromagnetic lock is considered to be a locking device comprising of an armature plate and an electromagnet. They are of two types. The locking devices can either be ‘fail secure’ or ‘fail-safe’. The former type remains locked even when power is not there. The fail-safe type is unlocked if de-energized. The direct pull locks are fail-safe. The lock’s electromagnet portion is typically attached to a door frame, while the door is attached with the mating armature plate. As the door gets closed, both the components come in contact with one another. As there is energizing of the electromagnet, there is passed current via the electromagnet, thus generating magnetic flux. This, in turn, causes attraction of the electromagnet by the armature plate, thereby developing locking action. Since armature and electromagnet mating are is large, the magnetic flux developed force is very strong to ensure that the door remains locked even during stress.
The typical magnetic lock system for gates is found in 1200 lbs and 600 lbs dynamic holding force capacity. Power is required for the fail-safe type to stay locked all the time. High-security applications should not use this type since the lock can be disabled easily by power supply disruption. Apart from this, if the lock is added with a magnetic bond sensor and power supply which includes battery backup ability is used, then it becomes possible to implement few specialized high-security applications. Such locks are termed to be just perfect to be used for emergency exit doors having fire safety applications. This is because, no moving parts are present in them and hence, the chances to fail is very less, when compared to other electric lock types like electric strikes.
1, Strength and durability
When compared to conventional door locks, the magnetic lock access control does have good strength and also are more affordable to operate. The typical electromagnetic lock system comes installed with additional release hardware pieces. As these locks are not found to interact with the door knobs or levers, there is mounted a separate type of release button to cut off the power supply. A timer is present in the button, which pressed once unlocks for about 15-30 seconds. For unlocking the door on egress door side automatically, there is a present crash bar or motion sensor with an internal switch.
The principle that is behind the magnetic lock system for gates is to lock the door by using electromagnetism when energized. Holding force needs to be collinear with load, while the armature plate and lock to ensure the optimal operation is to be kept face to face.
3, Its operation
Some basic electromagnetism concepts are relied upon by the magnetic lock for proper functioning. An electromagnet is present that attracts conductor having force sufficient enough to ensure that the door does not open. A magnetic field is produced by the current that moves through loops of wire also called solenoid in the device, which works within free space. However, with solenoid wrapped around the ferromagnetic core like soft iron, the field effect is amplified greatly. The reason is, the material’s internal magnetic domains tend to align with one another to improve immensely density of the magnetic flux.
4, Installation process
For both out-swinging and in-swinging doors, the electromagnetic locks for doors are found to be quite compatible and useful. To orient, armature to be utilized with both the applications, there can be used brackets like L, LZ, and U type. Also are used filler plates to assure the door frame of having flat and large mounting area, if the electromagnet is found to be much larger than available mounting door frame space, because of frame geometry.
It is on the door’s secure side that installation of the magnetic look should be done, with the majority being surface mounted. Also needs to be routed wires, cables, and magnetic lock through flush mount or door frame with wire molding for enhanced safety.
The installation process is very easy. In case, of in-swinging applications, it is installed in the door’s opening corner at door header. Vertical installation in door opening can also be done if furnished with full-length housing. The armature configuration is bolted through a door as well as oriented towards mating with electromagnet face. To offer better locking holding force, electromagnet and armature plate are to touch.
For out-swinging applications, it is on the door header side that electromagnet gets installed. The armature in this configuration gets mounted upon Z shaped bracket to orient armature towards mating electromagnet.
It can be safely stated that magnetic locks has always been part of the advanced electronic security system and comprises of keycard reader or be much more complex to include the connection with the central computer. This helps to monitor and improve overall building security.