®
Form No. FWX 250
Page 1 of 2
BIF Doc #720005
Bussmann®
FWX 250V 35-2500A
Electrical Characteristics Ordering Information Dimensions Curves
Rated I2t (A2Sec) Carton
Current Clearing Watts Part Carton Weight Figure
Type RMS-Amps Pre-arc at 250V Loss Number Qty. (lbs) Number BIF #
35 50 230 4.2 FWX-35A
______________________________________________________________________________________
40 60 310 5.2 FWX-40A
______________________________________________________________________________________
45 80 390 5.7 FWX-45A 5 1.40
______________________________________________________________________________________
50 100 520 6.0 FWX-50A
______________________________________________________________________________________
60 140 740 8.1 FWX-60A
_____________________________________________________________________________________________________________
70 330 1400 7.2 FWX-70A
______________________________________________________________________________________
80 430 1850 8.1 FWX-80A
______________________________________________________________________________________
90 570 2450 9.0 FWX-90A
______________________________________________________________________________________
100 740 3150 10.0 FWX-100A 0.32 359
______________________________________________________________________________________
125 1130 4850 12.5 FWX-125A
______________________________________________________________________________________
150 1620 6950 15.7 FWX-150A
______________________________________________________________________________________
175 2170 9300 18.5 FWX-175A Fig. 1
______________________________________________________________________________________
200 2790 12000 22 FWX-200A
______________________________________________________________________________________ ______________
225 3210 14700 24 FWX-225A
______________________________________________________________________________________
FWX 250 3960 18100 27 FWX-250A
______________________________________________________________________________________
250V 275 4720 21600 31 FWX-275A
______________________________________________________________________________________
300 6000 27300 32 FWX-300A
______________________________________________________________________________________
350 10600 48600 39 FWX-350A 1 0.52
______________________________________________________________________________________
400 14500 66100 44 FWX-400A
______________________________________________________________________________________
450 22100 101000 49 FWX-450A
______________________________________________________________________________________
500 28000 128000 54 FWX-500A
______________________________________________________________________________________
600 41100 188000 62 FWX-600A
______________________________________________________________________________________ ______________
700 48800 190000 72 FWX-700A 0.90
______________________________________________________________________________________
800 59000 230000 84 FWX-800A
______________________________________________________________________________________
1000 44000 360000 100 FWX-1000AH Fig. 2
______________________________________________________________________________________
1200 92000 750000 103 FWX-1200AH
______________________________________________________________________________________ _____________
1500 120000 880000 140 FWX-1500AH 35785299
______________________________________________________________________________________
1600 160000 1200000 140 FWX-1600AH 2.86 Fig. 3
______________________________________________________________________________________
2000 320000 2300000 151 FWX-2000AH
______________________________________________________________________________________
2500 670000 4700000 163 FWX-2500AH
† U.L. Recognition on 35 through 800 amperes only. 1 kg = 2.2 l bs 1 lb = 0.45 kg
nInterrupting rating 200kA RMS Symmetrical.
nWatts loss provided at rated current.
n(250 Vdc/Interrupting rating 20kA) U.L. Recognition on 35 through 800 amperes only.
7-11-01 SB01191
†
The only controlled copy of this BIF document is the electronic read-only version located on the Bussmann Network Drive. All other copies of this document are by definition uncontrolled.
This bulletin is intended to clearly present comprehensive product data and provide technical information that will help the end user with design applications. Bussmann reserves the right,
without notice, to change design or construction of any products and to discontinue or limit distribution of any products. Bussmann also reserves the right to change or update, without
notice, any technical information contained in this bulletin. Once a product has been selected, it should be tested by the user in all possible applications.
Form No.FWX 250
Page 2 of 2
BIF Doc #720005
FWX 250V 35-2500A
AEDC
F
J
G
B
H
A
BC
A
BC
D
Order # Fig. A B C D E F G H J Thread Depth
FWX-35A-60A 1 3.19 0.81 1.59 2.59 2.25 0.34 0.63 0.13 0.52 —
FWX-70A-200A 1 3.13 1.22 1.59 2.44 2.19 0.34 1.00 0.19 0.47 —
FWX-225A-600A 1 3.84 1.50 1.59 2.94 2.25 0.41 1.00 0.25 0.75 —
FWX-700A-800A 1 3.84 2.00 1.59 3.03 2.28 0.41 1.50 0.25 0.78 —
FWX-1000AH-1200AH 2 2.59 3.00 1.50 — — — — — — Tapped ‹Ω•∑-24 ≈ ⁄Ω™∑
FWX-1500AH-2500AH 3 2.59 3.50 1.50 1.50 — — — — — Tapped ‹Ω•∑-24 ≈ ⁄Ω™∑
Dimension in inches.
1mm = 0.0394∑ 1∑ = 25.4mm
1.5
1.0
0.5
0.3
0.2
0.1575 125 300200 250 Eg
K
1)
2)
UL
1.4
1.2
103
800
600
500
400
300
20050 100 150 200 250
Eg
1)
2)
Kp
1.0
0.8
0.4
0.5
0.6
0.3
0.2
0.1 30 40 50 60 70 80 90 100%
Ib
Fig. 1: 35-800 Amp Range Fig. 2: 1000-1200 Amp Range Fig. 3: 1500-2500 Amp Range
1) 35-800 Amp Range
2) 1000-2500 Amp Range 1) 35-800 Amp Range
2) 1000-2500 Amp Range
Dimensions
Total Clearing I2t
The total clearing I2t at rated voltage and
at power factor of 15% are given in the
electrical characteristics. For other volt-
ages, the clearing I2t is found by multi-
plying by correction factor, K, given as
a function of applied working voltage,
Eg, (RMS).
Arc Voltage
This curve gives the peak arc voltage,
UL, which may appear across the fuse
during its operation as a function of the
applied working voltage, Eg, (RMS) at a
power factor of 15%.
Power Losses
Watts loss at rated current is given in
the electrical characteristics. The curve
allows the calculation of the power
losses at load currents lower than the
rated current. The correction factor, Kp,
is given as a function of the RMS load
current, Ib, in % of the rated current .
Electrical Characteristics
7-11-01 SB01191
®†
Bussmann®
