assaabloy.com 641 Electromechanical locking Electric locks come in many forms and work in association with a variety of access control systems. As a world leader we have a comprehensive range of locking solutions from electric strikes and magnets to motor locks, which offer high levels of security, functionality and sustainability. When specifying locking devices – risk to life versus security must be considered, so whether a locking device is 'fail safe' or 'fail secure' should be a main factor. No matter which access control system you have, we have an electric locking solution to suit. Useful terminology Electromechanical locking Introduction Terminology Explanation Fail safe, fail open or power to lock (PTL) When power to the lock is removed via mains failure, fire or management system - the lock is disengaged, which means the door is unlocked for escape. Fail secure, fail locked or power to open (PTO) When power to the lock is removed via mains failure, fire or management system - the lock is engaged, which means the door is locked for security. Monitoring Relays the status of the lock (open or closed) back to building management / alarms systems. Preload test Ensures the lock still engages and doors continue to operate despite pressures exerted by door seals, air flow and misaligned doors. Alternating current power (AC) Alternating current (AC) is an electric current which periodically reverses direction and changes its magnitude continuously with time. Most of the low-cost door entry systems operate on AC, which produces a buzzing sound. AC strikes are only available as fail secure. Direct current power (DC) Direct current (DC) is one-directional flow of electric charge. An electrochemical cell is a prime example of DC power. DC may flow through a conductor such as a wire, but can also flow though semiconductors, insulators, or even through a vacuum as in electron or ion beams. The electric current flows in a constant direction. More sophisticated systems operate on DC allowing for continuous, silent, fail safe or fail secure operation. Power supply units (PSU) Power supply units (PSU) are not just power supply systems, they are actually power convertors that convert AC high voltage current into DC, they also regulate DC output voltage to tolerances required for modern components. Correctly specifying PSU’s will help ensure fault-free use and ensure the PSU puts out the correct voltage required to run electric locks within stated tolerances, thus extending the life of the components connected to it. Metal oxide varistor (MOV) A Metal Oxide Varistor is a voltage suppression device that filters and clamps the transient in an electrical circuit. ANSI standard short faceplate strike The ANSI (American National Standards Institute) standard short faceplate strike is the standard strike for aluminium doors. A longer face plate variant is available making the ANSI style strike suitable for use in timber door applications. Fail safe or fail secure? PS PS Power NOT interrupted Power NOT interrupted Locked Unlocked PS PS Power interrupted Power interrupted Unlocked Locked PS = Power supply Fail safe Fail secure
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