Page 38 - Ferraz semiconductor BS88

Semiconductor fuses
Semiconductor (AC) fuses

®
Other Protistor Fuses
BS88-4 Fuses
17x49 gRB/URB - 690 VAC

2
Total clearing I t I t corrective factor
2
K
2
2
I t (A s) 1.4
1.2
5
10
10 ms (5 ms) 10 ms (2,8 ms) 8 ms (2 ms) 7 ms (1,5 ms) 6 ms (1,3 ms) 5 ms (1 ms) 4 ms (0,8 ms) 3 ms (0,6 ms) 2 ms (0,4 ms) 1,5 ms (0,3 ms) 1 ms (0,2 ms) 1.0 Left: Curve shows variation of
2
total clearing time (I t ) and total
0.8
t
clearing duration T as a function
t
0.6 of operating voltage U.
4
10
100 A 0.4
90 A
80 A
75 A 0.2
63 A
0
3 55 A 0 200 400 600 800 U (V)
10 50 A
45 A
40 A Peak arc voltage
35 A
32 A
25 A Um (V)
10 2 20 A
16A
12 A 1600
Left: Curve shows peak value
1400
Um of arc voltage which
10
1200 appears across fuse-link as a
2 3 4
10 10 10 10 function of operating voltage
Ip (A)
U@ cos ϕ = 0.15
Above: Horizontal curves show for each rated current maximum
values of total clearing I t (I t ) as a function of prospective
2
2
t
current I . @ 690 V.
p
cos ϕ = 0.15.
Oblique lines indicate total clearing duration Tt and associated
pre-arcing duration in brackets. 0 200 400 600 700 U (V)
Time vs current characteristics Current limitation curves
16 25 35 55 75 90 I =100 A, aR class with CC’ I (A)
N
C
t (s) 35 45 limiting curve.
12 20 32 50 63 80 100
10 4 10 5 5
a= 130
3 A2=0.6
10
B1= 1.25
B2= 0.6 Ic = 2.5 Ip
Cf3= 0.8 10 4 4
10 2 C C’ Ic = 2 Ip
10
10 3 3
1
10 -1
10 -22
10 -2
-3
10
10
1 2 3 4 5
2 3 4
10 10 10 10
10 -4
I (A) Ip (A)
2 3 4
10 10 10 10
Tolerance for mean pre-arcing current ± 9%. Above: Curves show, for each rating, value of peak let-
through current IC as a function of available fault current Ip.
Above: Curves indicate, for each rated current, pre-
arcing time vs. R.M.S. pre-arcing current
SCAC228 12/04