120 / 132
120
technical
information
key to characteristic curves
n
Characteristic curves
The graphs on the following pages detail the characteristic curves
of each circuit breaking device
Complying with isolation requirements, the units are provided with
fully visible contact indication and a lock-off facility
n
Time/current characteristics : thermal-magnetic
Reference ambient temperature 40 °C (DPX)
l
= actual current
lm = short-circuit operating time
lr
= operating current
1
= thermal release from cold
2
= thermal release from hot
Tolerance of magnetic release ±20%
n
l
2
t/lcc characteristics
lcc = prospective symmetrical short-circuit current
(mms value - A)
l
2
t
= specific let through energy (A
2
s)
n
Limiting characteristics
lcc = prospective symmetrical short-circuit current
(mms value - A)
lp = maximum peak value of current
= maximum peak values of short-circuit current
corresponding to power factors indicated above
= maximum peak values of actual short-circuit current
n
Time/current characteristics : earth fault protection
ln
= residual operating current (sensitivity)
t
= operating time