High Speed Fuses
Section Contents
Page
General Applications . . . . . . . . . . . . . . . . . . . . . . . . . . . 88-89
North American fuses & accessories . . . . . . . . . . . . 90-106
Square Body fuses & accessories . . . . . . . . . . . . . 107-180
BS 88 fuses & accessories . . . . . . . . . . . . . . . . . . . .181-190
Ferrule fuses & accessories. . . . . . . . . . . . . . . . . . . .191-212
Fuses
87
High Speed Fuses
General applications
Rated Voltage
The ac voltage rating of Cooper Bussmann
®
fuses is given in
volts rms. Fuses tested to IEC are tested at 10% above their
rated voltage. British Style BS 88 fuses are tested at 5%
above its rated voltage. UL recognition tests are performed
at
the rated voltage.
Rated Current
Rated current is given in amperes rms. Cooper Bussmann
fuses can continuously carry the rated current.
Melting Characteristic
The melting char-
acteristic shows
the virtual melting
time in seconds as
a function of the
prospective current
in amperes rms.
The fuses are spe-
cially constructed
for short-circuit pro-
tection against high
level fault currents.
Loading and opera-
tion of the fuse in
the non-continu-
ous/dashed section
of the melt curve
must be avoided.
The curve can also
be read as the real
melting time as a
function of the
RMS value of the
pre-arc current.
Clearing Integrals
The total clearing I
2
t at
rated voltage and at
power factor of 15% are
given in the electrical
characteristics. For
other voltages, the
clearing I
2
t is found by
multiplying by correction
factor, K, given as a
function of applied work-
ing voltage, Eg, (rms).
1.5
K
1.0
10
4
6
4
2
10
3
6
4
2
10
2
6
4
2
Virtual Pre-Arcing Time In Seconds
10
1
6
4
2
10
0
6
4
2
10
–1
6
4
2
10
–2
6
4
2
10
–3
6
4
2
10
–4
For other power factor
values, the total clearing
integral can be calculat-
ed as a multiple of the
clearing integrals, the
correction factor K and
the correction factor X.
X
1.0
0.9
0.8
Arc Voltage
This curve gives the
peak arc voltage, U L ,
which may appear
across the fuse during its
operation as a function
of the applied working
voltage, E g , (rms) at a
power factor of 15%.
Power Losses
0.7
0.1
0.2
0.3
0.4
0.5
COS
1.4
1.2 U
L
10
3
9
8
7
6
5
4
3
E
g
200 300
1.0
K
p
0.8
0.6
0.5
0.4
0.3
0.2
400
500
600 660
10
1
2
4
6
8 10
2
2
4
6
8 10
3
Prospective Current In Amperes RMS
Watts loss at rated cur-
rent is given in the electri-
cal characteristics. The
curve allows the calcula-
tion of the power losses
at load currents lower
than the rated current.
The correction factor, K p ,
is given as a function of
the RMS load current, Ib ,
in % of the rated current .
Cut-Off Current
0.1
30 40 50
60
70
I
b
80 90 100%
0.5
0.4
0.3
A fuse operation relating to short-circuits only. When a fuse
operates in its current-limiting range, it will clear a short-cir-
cuit in less than
1
⁄
2
cycle. Also, it will limit the instantaneous
peak let-through current to a value substantially less than
that obtainable in the same circuit if that fuse were replaced
with a solid conductor of equal impedance.
10
5
Peak Let-Through Current
0.2
E
g
100 200 300 400 500 600 660
10
4
10
3
A
B
2
≈
10
2
10
2
10
3
10
4
Prospective Current in Amperes RMS
10
5
10
6
A asymmetrical current
B symmetrical current
88
For product data sheets, visit www.cooperbussmann.com/products/datasheet.asp
High Speed Fuses
General applications
Parallel Connection
When fuses are connected in parallel it is recommended that
the applied voltage does not exceed 0.9 UN (the rated volt-
age of the fuse). This is due to the fact that the energy
released within the fuses may be unevenly shared between
the parallel connected barrels.
When fuses are connected in parallel, one must take into
account that the current sharing is not necessarily equal.
And it must be checked, that the maximum load current is
not exceeded.
Series Connection
Fuses in series may not equally divide the applied voltage. It
is recommended that series connected fuses should only be
operated at fault currents that yield melting times less than
10 ms and a recovery voltage per fuse of less than or equal
to 0.9 UN (the rated voltage of the fuse).
Mounting Guidance
The recommendations below have to be followed when
mounting a Cooper Bussmann fuse with end plate threaded
holes.
1. Screw in studs: 5 N•m Max, 3 N•m Min
2. Attachment of the fuse to buss-bar by means of nut and
washer:
Thread
Configuration
5
⁄
16
” – 18, M8
3
⁄
8
” – 16, M10
3
⁄
8
” – 24
1
⁄
2
” – 13, M12
1
⁄
2
” – 20
*1 N•m = 0.7375 lb-ft
Torque (N•m)*
Max
Min
25
20
45
40
45
40
65
50
65
50
Frequency of Occurrence
Less than once per month
Less than twice per week
Several times per day
Overloads (> 1 sec)
Imax < 80% x It
Imax < 70% x It
Imax < 60% x It
Impulse Loads (< 1 sec)
Imax < 70% x It
Imax < 60% x It
—
When impulse loads are an intrinsic/normal parameter of the
load current either as single pulse or in trains of pulses or
when their level is higher than the melting current at 0.01
seconds (per time-current curve), contact Cooper Bussmann
for application assistance.
In addition to the parameters set forth in the preceding table,
the RMS value of the load current as calculated for any
period of 10 minutes or more should not exceed the maxi-
mum permissible load current.
Furthermore, it is important that a fuse should not be applied
in the non-continuous/dashed portion of the associated
time-current curve.
Any time-current combination point which falls in the
non-continuous/dashed portion of the time-current curve is
beyond the capability of the fuse to operate properly.
DC Operation
Depending upon the short-circuit time constant and the mag-
nitude of the prospective short-circuit current, the dc voltage
at which a fuse can be applied may be less than its ac rating.
Long time constants require a lower dc voltage. Conversely,
however, higher available prospective short-circuit currents
result in faster fuse openings and thus permit a fuse to be
operated at a higher dc voltage.
Consult Cooper Bussmann for additional information and
application assistance when fuses have to operate under dc
conditions.
Load Current Versus
Conductor Cross
Section
1 .0
Reduction Factor
Fuses
Overloads
The design of Cooper Bussmann
®
fuses is such that they
can be operated under rather severe operating conditions
imposed by overloads (any load current in excess of the
maximum permissible load current).
In applications, there will be a maximum overload current,
Imax, which can be imposed on the fuse with a
corresponding duration and frequency of occurrence.
Time durations fall into two categories:
1. Overloads longer than one second
2. Overloads less than one second termed “impulse” loads.
The following table gives general application guidelines
which, in the expression Imax < (% factor) x It. It is the melt-
ing current corresponding to the time “t” of the overload dura-
tion as read from the time-current curve of the fuse. The
guidelines in the table below determine the acceptability of
the selected fuses for a given Imax.
Reduction of permissible
load current when the
0 .9
conductor cross section is
less than that given in IEC
0 .8
Publication 269-1 & 4
valid for Cooper
0 .5 0 .6 0 . 7 0 .8 0.9
Bussmann semiconductor
≈ (IEC cross section)
fuses.
Application Assistance
1 .0
If you have application problems or need a fuse outside our
standard program, please contact the nearest Cooper
Bussmann representative. Phone numbers are shown on the
back cover.
For product data sheets, visit www.cooperbussmann.com/products/datasheet.asp
89
High Speed Fuses
North American fuses
Introduction
North American Contents
Catalog
Number
FWA
FWA
FWX
FWH
KAC
KBC
FWP
FWJ
Volts
130
150
250
500
600
600
700
1000
Amp
Range
1000-4000
70-1000
35-2500
35-1600
1-1000
35-800
5-1200
35-2000
Page
91-92
93-94
95-96
97-98
99
100
101-103
104-105
General Information
Cooper Bussmann offers a complete range of North
American blade and flush-end style fuses and accessories.
Their design and construction were optimized to provide:
• Low energy let-through (I
2
t)
• Low watts loss
• Superior cycling capability
• Low arc voltage
• Excellent dc performance
North American style fuses provide an excellent solution for
medium power applications. While there are currently no
published standards for these fuses, the industry has
standardized on mounting centers that accept
Cooper Bussmann fuses.
Voltage Rating
All Cooper Bussmann
®
North American style fuses are tested
at their rated voltage. Cooper Bussmann should be consulted
for applications exceeding those values.
Accessories
External and internal open fuse indication is available for
selected portions of the North American line. Fuse blocks are
available for most applications.
Accessories
Fuse Bases
North American Fuse Ranges
Amps
1000-4000
70-1000
35-2500
35-1600
1-1000
5-1200
40-600
35-2000
Volts
130
150
250
500
600
700
800
1000
AC
X
X
X
X
X
X
—
X
DC
X
X
X
X
—
X
X
—
106
90
For product data sheets, visit www.cooperbussmann.com/products/datasheet.asp
High Speed Fuses
North American — FWA 130V: 1000-4000A
FWA
Specifications
Description:
North American
style flush-end high speed fuses.
Dimensions:
See Dimensions
illustrations.
Ratings:
Volts: — 130Vac
Amps: — 1000-4000A
IR: — 200kA RMS Sym.
— 50kA @130Vdc
Agency Information:
CE, UL Recognized on 1000-2000A
fuses
Electrical Characteristics
Total Clearing I
2
t
The total clearing I
2
t at
rated voltage and at power
factor of 15% are given in
the electrical characteris-
tics. For other voltages, the
clearing I
2
t is found by
multiplying by correction
factor, K, given as a func-
tion of applied working
voltage, Eg, (rms).
1.5
K
1.0
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 fac-
tor 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 correc-
tion factor, Kp, is given as
a function of the RMS load
current, Ib, in % of the
rated current.
Catalog Numbers
Catalog
Numbers
FWA-1000AH
FWA-1200AH
FWA-1500AH
FWA-2000AH
FWA-2500AH
FWA-3000AH
FWA-4000AH
Electrical Characteristics
I
2
t (A
2
Sec)
Rated Current
Clearing
RMS-Amps
Pre-arc
at 130V
1000
170000
460000
1200
270000
730000
1500
520000
1400000
2000
860000
2400000
2500
1500000
4100000
3000
2100000
5700000
4000
3400000
9200000
Watts
Loss
60
70
78
108
130
150
257
1.0
K
p
0.8
0.6
0.5
0.4
0.3
0.2
U
L
300
200
100
E
g
50
100
150
Fuses
0.1
30 40 50
60
70
I
b
80 90 100%
0.5
0.3
0.2
0.15
26
E
g
65
104
130
Dimensions (in)
Catalog Number
FWA-1000AH-2000AH
FWA-2500AH-3000AH
FWA-4000AH
1mm = 0.0394∑ / 1∑ = 25.4mm
• Watts loss provided at rated current.
• See accessories on page 106.
Fig.
1
1
2
B
2.0
3.0
3.5
C
1.0
1.5
1.5
D
—
—
1.5
Thread Depth
Tapped
3
⁄
8
”-24 x
1
⁄
2
”
Tapped
1
⁄
2
”-20 x
1
⁄
2
”
Tapped
1
⁄
2
”-20 x
1
⁄
2
”
Fig. 1: 1000-3000A
Fig. 2: 4000A
Features and Benefits
• Excellent dc performance
• Low arc voltage and low energy let-through (I
2
t)
• Low watts loss
• Superior cycling capability
Typical Applications
• DC common bus
• DC drives
• Power converters/rectifiers
• Reduced voltage starters
1.875
1.875
D
B
C
B
C
For product data sheets, visit www.cooperbussmann.com/products/datasheet.asp
91