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The second problem is when any load is operated in parallel with the Magnalock. A good example would be adding an incandescent lamp in parallel with the lock so that the lamp would be illuminated when the lock is powered. The lamp acts like a resistor and allows current recirculation which will greatly slow lock release time. When you want to add a resistive load in parallel with the lock, you must put a forward diode in series with the resistive load. This will block recirculation and restore quick release. Correct practice is shown in Figure 12 below.
A special case exists when you use an LED connected in parallel with the Magnalock (to show that the Magnalock is on for example). This does not slow release as the LED does not allow recirculation but the limited recirculation energy will eventually burn out the LED. LED’s are susceptible to even a tiny amount of reverse voltage. Therefore add the forward diode as you would with an incandescent lamp (see Figure 12) to extend the life of the LED.
FIG. 12: WIRING CONSIDERATIONS TO AVOID SLOW RELEASE
RED
BLACK
NEVER CONNECT PARALLEL REVERSE DIODE AS SHOWN
RED
MAGNALOCK
BLACK
USE A FORWARD DIODE WITH ANY PARALLEL RESISTIVE LOAD SUCH AS A LAMP
3.4 WIRE GAUGE SIZING
If the power supply is distant from the lock, voltage will be lost (dropped) in the connecting wires so that the Magnalock will not receive full voltage. The following chart shows the minimum wire gauge that will hold voltage drop to an acceptable 5% for different lock to power supply distances. Proper use of the chart assumes a dedicated pair of wires to power each Magnalock (no common negative). Note that a Magnalock operating on 24 volts is a much better choice for long wire runs as it has 4 times the resistance of a 12 volt installation. Also note that the correct calculation of wire sizing is a very important issue as the installer is responsible to insure that adequate voltage is supplied to any load. In multiple device installations, the calculation can become quite complex so refer to Appendix B for a more complete discussion.
Distance | Gauge 12V | Gauge 24V | Distance | Gauge 12V | Gauge 24V |
80 FT | 20 GA | 24 GA | 800 FT | 10 GA | 16 GA |
200 FT | 17 GA | 22 GA | 1500 FT. | 8 GA | 14 GA |
400 FT | 14 GA | 20 GA | 3000 FT | N/A | 12 GA |
3.5 SENSTAT MAGNALOCKS: “SC”
Securitron's optional patented Senstat feature provides true lock status sensing. In many electrically controlled door security systems, status sensing is provided by a magnetic switch on the door itself. This indicates the door is closed but not necessarily secured. Securitron's Senstat monitors the lock rather than the door and therefore provides higher security (but note that it can’t be used as an
An “SC” Magnalock provides a dry SPDT output which changes state when the lock is reporting secure (1 Amp @ 30 VDC maximum). This is accomplished by conducting the input power of the lock through the strike and employing it to energize an internal SPDT relay. The white wire is the Senstat relay common. Green is closed to white when the lock is secure and Orange is closed to white when the lock is not secure.
