List of abbreviations
A.1 List of abbreviations
Selectivity for 3VA molded case circuit breakers
74 Configuration Manual, 08/2016, A5E03603181010-01
Table A- 2 Meaning of symbols and abbreviations
Sym-
bol/abbreviation
Meaning
I
2
t Let-through energy
I
cn
Rated breaking capacity; rated short-circuit breaking capacity
I
cu
Maximum short-circuit breaking capacity (total selectivity); rated ultimate short-
circuit breaking capacity
I
cw
Rated short-time withstand current; rated short-time current
I
D
Let-through current
I
i
Instantaneous tripping current; instantaneous short-circuit protection; instantaneous
magnetic protection; rated tripping current of instantaneous trip
I
k
Short-circuit current
I
K MAX
Maximum short-circuit current
I
rated
Rated operational current
I
P
Prospective current
I
r
Thermal protection; setting current; response value; current setting value of ad-
justable overload protection (pickup value overload protection)
I
s
Selectivity limit current; maximum short-circuit current for selectivity limit
I
sd
Short-time delay tripping current; response current of S release; short-time delay
short-circuit release; short-time delay short-circuit protection; delay time of S relea-
se
K
t-I
Characteristic displacement factor
t
A
Safety margin
t
i
"Virtual" trip time of I protection; highest trip time associated with rated tripping
current of instantaneous trip
t
r
Trip time associated with current setting value of adjustable overload release
t
sd
Trip time associated with short-time delay tripping current; delay time of S release
t
S
Fuse pre-arcing time
t
ZSI
Delay time of all molded case circuit breakers which detect the short-circuit but do
not receive a "block" signal when ZSI is activated.
U
LB
Peak arc voltage
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