SCAC191
Semiconductor fuses
Semiconductor (AC) fuses
Other Protistor®Fuses
Ferrule Fuses
27x60 gRB - 800 VAC
12/04
Total clearing I2t
t (s)
Time vs current characteristics
10 110 210 310 4
10 4
10 3
10 2
10
1
10 -1
10 -2
10 -3
10 -4
Left: Curves show, for
each rated current,
pre-arcing time vs.
R.M.S. pre-arcing cur-
rent
.
Tolerance for
mean pre-arcing
current ± 8%.
gRB
a=130
A2=0.6
B1=1.25
B2=0.6
Cf3=0.8
810
12 16
20 25
32 40
50 63
80 100
110
10 4
10 3
10 2
10 1
10 5
10 4
10 3
10 2
10 1
Current limitation curves
10 110 210 310 410 5
10 110 210 310 410 5
IC(A)
110 A
100 A
80 A
63 A
50 A
40 A
32 A
25 A
20 A
16 A
12 A
10 A
8 A
110 A
100 A
80 A
63 A
50 A
40 A
32 A
25 A
20 A
16 A
12 A
10 A
8 A
I (A)
Below: Curves show, for each rating, value of peak let-through
current Ic as a function of available fault current Ip.
I2t corrective factor
Left: Curve enables com-
putation of power losses
P for a IN-rated fuse as a
function of the R.M.S.
current I (as a multiple of
INfor steady state opera-
tion)
Watts loss
Left: Mean curve
shows variation of
total clearing time (I2tt)
and total clearing
duration Tt as a
func-
tion of operating vol-
tage U.
U (V)
0
100
200
300
400
500
600
700
800
900
90
80
70
60
50
40
30
20
10
0
Above: Curves indicate permissible value of time cons-
tant L/R as a function of DC working voltage.
1
- INfrom 80 to 110 A /
2
- INfrom 25 to 63 A
3
- INfrom 8 to 12 A
Ip (A)
Ip (A)
1 2
3
1
- L/R = 60 ms /
2
- L/R = 30 ms
Above: Curve indicates peak arc voltage Um
which may appear across fuse terminals at
working voltage U
, for different values of time
constant L/R of the fault circuit.
Above: Horizontal curves show maximum values of total clearing I2t (I2tt) as function
of prospective current Ip. @ UN.with cosϕ= 0.15.
Oblique lines indicate total clea-
ring duration Tt and associated pre-arcing duration in brackets.
U (V)
0
500
2000
1000
0
U (V)
1
2
DC Application data
L/R(ms)
Ic (A)
I/IN
U(V)
P/PN
Um(V)
K
Um (V)