User's Manual

How to Install the ISONAS IP-Enabled Reader-controller 36
2.2.12: MANAGING IN-RUSH CURRENT LOADS
Some Magnetic Locks with advanced quick-release circuitry will generate an initial
surge of current when the lock is turned on. This surge of current can be 20 times
greater than the lock’s steady state current requirements. The lock control relay is
rated for 1 amp of current. This in-rush current can greatly exceed that rating, and
shorten the useful life of the reader-controller.
Figure 20 shows
the solution to this.
Installing an in-
rush suppressor in
the lock circuit will
prevent any
detrimental affects
on the reader-
controller.
F
Figure 20
Any installation that is using Magnetic Locks that are equipped with a “quick-
release feature” should have this in-rush protection installed.
Other devices who also create this in-rush current include incandescent light bulbs
and “capacitive loads”. A light bulb’s cold resistance is close to 0 ohms, and a
discharged capacitor is also a short-circuit when power is initially applied. Any
installation which is controlling these types of devices should have the in-rush
suppressor installed.