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An electric current typically energizes the electromagnet to attract and hold the steel plate, keeping the door open. Unlike electromagnetic locks, the magnetic attraction of an electromagnetic door holder is usually weak enough that it can be manually overpowered at any time by anyone, allowing the door to close. [citation needed]
The principle behind an electromagnetic lock is the use of electromagnetism to lock a door when energized. The holding force should be collinear with the load, and the lock and armature plate should be face-to-face to achieve optimal operation. The magnetic lock relies upon some of the basic concepts of electromagnetism.
A magnetic keyed padlock A magnetic keyed padlock. A magnetic keyed lock or magnetic-coded lock is a locking mechanism whereby the key utilizes magnets as part of the locking and unlocking mechanism. Magnetic-coded locks encompass knob locks, cylinder locks, lever locks, and deadbolt locks as well as applications in other security devices.
A "horseshoe magnet" made of Alnico 5, about 1 inch high.The metal bar (bottom) is a keeper. A magnet keeper, also known historically as an armature, is a bar made from magnetically soft iron or steel, which is placed across the poles of a permanent magnet to help preserve the strength of the magnet by completing the magnetic circuit; it is important for magnets that have low magnetic ...
The card stores a physical or digital pattern that the door mechanism accepts before disengaging the lock. There are several common types of keycards in use, including the mechanical holecard, barcode , magnetic stripe , Wiegand wire embedded cards, smart card (embedded with a read/write electronic microchip ), RFID , and NFC proximity cards.
A metal doorframe with a strike plate built in: in other doors this would be a metal strikeplate in a wooden doorframe. The term door security or door security gate may refer to any of a range of measures used to strengthen doors against door breaching, ram-raiding and lock picking, and prevent crimes such as burglary and home invasions. Door ...
"Soft" magnetic materials with low coercivity and hysteresis, such as silicon steel, or ferrite, are usually used in cores. Magnetic field (green) created by a current-carrying winding (red) in a typical magnetic core transformer or inductor, with the iron core C forming a closed loop, possibly with air gaps G in it. The drawing shows a section ...
Hurricane ties are in place at the top of the wall as the roof trusses are being placed. A hurricane tie (also known as hurricane clip or strip) is used to help make a structure (specifically wooden structures) more resistant to high winds (such as in hurricanes), resisting uplift, racking, overturning, and sliding. [3]