APG FLE Series user manual - Manual (Page 8)

FLE Series Rev. A3, 10/08
8
Automation Products Group, Inc.
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• Circuit Protection
WARNING!
DO NOT EXCEED CONTACT RATINGS! When an inductive load is
used (e.g. a motor, a coil, or an electromagnetic relay), a back
electromotive force of several hundred volts (energy stored in the
inductance) arises when the contacts are opened. This results in
considerable decrease in contact life. The same result arises even
when a resistive load is used with a high voltage or a large current. The
figures below show circuits for protecting the reed switch(s) from the
back electromotive force.
L
C
R
E
C = I
R = Approx.
10 x I (I + 50/E)
E
Protecting Circuit Using CR Protecting Circuit Using Varistor Protecting Circuit Using Diode
2 /10 (uF)
Switch Code A Code B
Max. contact capacity 20 VA 50 VA
Max. switching current 0.5A AC 0.5 A AC
Max. Voltage 220 VAC 220 VAC