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segments. The Senstat output should then report secure. This shows that the problem lies in the strike not making
correct flat contact with the magnet face. If the scissors technique doesn't cause the lock to report secure, check to
see if there is a broken Senstat wire. If this is not the case, the lock must be returned to the factory for
replacement.
PROBLEM
-- The lock does not release.
When power is removed from it, the SAM releases as magnetic attraction is gone and the angles on the edges of
the conical button “ramp” the strike off the magnet face. If the unit fails to release, the first possible cause to
consider is that power may not have been successfully removed. This is generally a wiring integrity problem. What
happens is that an upstream switch removes power from the wires going to the Magnalock, but through an
installation error, the wires have their insulation abraded between the switch and lock so that partial or full power
can leak in from another Magnalock or other DC device with similarly abraded wiring. This is most likely to occur at
the point where the wire cable leaves the lock case and enters the door frame. Another area is via an improper
splice on wiring in conduit. Either a metal door frame or the metal conduit is capable of leaking power between
multiple devices with abraded wires, thereby bypassing switches. A good way to check this electrically (as
opposed to visually removing and inspecting the wires) is to use a meter and check for leakage between the power
supply positive or negative and the door frame and conduit. Magnalocks should be powered by isolated DC
voltage without any earth ground reference to positive or negative. A second possible cause is mechanical
bonding via vandalism. By mechanical bonding, we simply mean that glue has been applied between the strike
and magnet as a prank. Finally, the SAM will not release if the strike plate is not able to pull away from the magnet
body when power is cut. The strike may somehow have become wedged against the edge of the door. This is
easily detectable by manually attempting to move the strike towards and away from the magnet body.
PROBLEM
-- Apparent electronic noise interference with the access control system.
Electric locks, being inductive devices, return voltage spikes on their power wires and also emit microwave
radiation when switched. This can interfere with access control electronics causing malfunctions. Access control
contractors often employ installation techniques designed to isolate the access control electronics from the electric
lock. These include separate circuits for the lock, shielded wiring and other techniques. These techniques will vary
with the sensitivity of the access control system electronics and should, of course, be followed. Note that SAM’s
include internal electronics which suppress both inductive kickback and radiation. They have been extensively
tested and accepted by numerous access control manufacturers and have been used in thousands of installations
without incident. An apparent noise problem is therefore usually not caused by the Magnalock. The access control
equipment may be itself faulty or have been installed improperly.
IF YOUR PROBLEM PERSISTS
CALL SECURITRON TOLL FREE
1-800-MAG-LOCK
APPENDIX B
CALCULATING WIRE GAUGE SIZING
The general practice of wire sizing in a DC circuit is to avoid causing voltage drops in connecting wires which
reduce the voltage available to operate the device. As the SAM is a low power device, it can be operated a long
distance from its power source.
For any job that includes long wire runs, the installer must be able to
calculate the correct gauge of wire to avoid excessive voltage drops.
This is done by adding the resistance of the Magnalock to the resistance in the power wires and then dividing the
wire resistance by the total resistance. This yields the fraction of voltage drop in the wires. For example, a SAM
operating on 24 volts has a resistance of 140 ohms. If the wires completing the circuit between the Magnalock and
its power source have a resistance of 10 ohms, the total resistance is 150 Ohms. Dividing 10 Ohms (the wire
resistance) by 150 (the total resistance) yields roughly 1/15 or 6.7%. With an input voltage of 24 volts, 6.7% of this