D 103
D
FRENCH CYLINDRICAL
821cp gRB SEMICONDUCTOR PROTECTION FUSES
Total clearing I2tDC Voltage Capabilities vs. Time Constant
Peak let-thru Data Clearing i2t vs. Operating Voltage
Melting Time Current Data
Peak arc voltage
Watts loss Correction
Above: Horizontal curves show maximum values of total clearing I2t (I2tt) as function
of prospective current lp. @ UNwith cosj = 0.15 Oblique lines indicatye total
clearing duration Tt and associated pre-arching duration in brackets.
Provides the DC voltage capability of a fuse as a
function of the circuit time constant.
Below: Curves show, for each rating, value of peak let-through
current Ic as a function of available fault current ip.
Correction Factor
to determine the
clearing I
2
t of a fuse
operating below its
rated voltage
Determines the peak
arc voltage across
the fuse terminals as
a function of applied
voltage.
Correction factor to
determine watts loss
value of a fuse
operating below its
rated current.
Left: Curves show,
for each rated
current, pre-arching
time vs. R.M.S.
pre-arching current.
Tolerance for mean
pre-arching current
±
8%.
1 - L/R = 60 ms / 2 - L/R = 30 ms
Above: Curves indicate peak arc voltage Um
which may appear across fuse terminals of
working voltage U, for different values of
time constant L/R of the fault circuit.
2000
1800
1600
1400
1200
1000
800
600
400
200
0
0 100 300 500 700 800
U (V)
Um (V)
DC Peak Arc Voltage