Key Management Systems Ltd
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P a g e
Locks
Locks are powered directly via either the System Controller or Lock Controller. Each
output can supply up to 2 Amps DC dependant on power supply specification.
All locks MUST be suitably suppressed using either a Metal Oxide Varistor (as
supplied) or 1N4000 series diode, all suppressants to be fitted at lock. Back E.M.F.
from locks can produce high return voltages capable of destroying system
components.
Lack of proper lock suppression may result in long term damage to system
components. Damage due to back E.M.F. is NOT covered under warranty.
Refer to the lock manufacturer’s documentation for information on individual locks.
All Fail-Safe or
‘power to lock’
locking devices must always be wired through a
mechanical egress device, these being Request to Exit buttons (RTE) and often
emergency break glasses.
KMS would recommend the lock +12v connection is wired through the RTE normally
closed contacts, this will ensure the +12v connection is broken on exit as well as the
system de-energising the 0v.
Lock Suppression
A Metal Oxide Varistor (MOV) MUST be fitted across the cables feeding power to the
electrical or magnetic lock. The MOV will suppress the back E.M.F. spike returning to
the host controller when power is removed from the lock. The MOV should be fitted
as close as possible to the electric or magnetic lock. Failure to properly supress locks
will void any warranties to that piece of equipment.
