Datasheet
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
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, K
p
, is given as
a function of the RMS load
current, I
b
, in % of the
rated current.
Catalog Numbers
EElleeccttrriiccaall CChhaarraacctteerriissttiiccss
RRaatteedd II
22
tt ((AA
22
SSeecc))
CCaattaalloogg CCuurrrreenntt CClleeaarriinngg CClleeaarriinngg WWaattttss
NNuummbbeerrss TTyyppee RRMMSS--AAmmppss PPrree--aarrcc aatt 112200VV aatt 224400VV LLoossss
6LCT 6 2 6 9 1.0
10LCT 10 3.8 12 22 2.5
12LCT LCT 12 7 22 32 2.5
16LCT 16 20 50 100 2.5
20LCT 20 25 80 160 4.0
25LET 25 18 120 250 4.0
32LET 32 32 200 450 5.0
35LET 35 50 320 600 5.0
50LET 50 100 500 1400 7.0
63LET LET 63 180 1100 2200 9.0
80LET 80 300 1900 3800 10.0
100LET 100 600 3800 7500 10.0
125LET 125 600 3800 7500 16.0
160LET 160 1100 7000 16000 20.0
180LETa 180 1600 12000 29000 21.0
160LMT 160 1100 7000 16000 17.0
200LMT 200 1500 10000 20000 28.0
250LMT 250 3200 20000 40000 28.0
315LMT LMT 315 6000 35000 75000 35.0
355LMT 355 8000 50000 100000 35.0
400LMT 400 14000 70000 160000 40.0
450LMT 450 18000 100000 220000 42.0
400LMMT 400 6000 35000 80000 60.0
500LMMT 500 14000 80000 170000 64.0
630LMMT
LMMT
630 24000 150000 300000 75.0
710LMMT 710 32000 200000 460000 77.0
800LMMT 800 52000 300000 600000 82.0
900LMMT 900 75000 400000 800000 97.0
• Watts loss provided at rated current.
• Note: 7LET, 10LET, 12LET and 16LET are available for replacement purposes on existing
equipment.
• See accessories on page 195.
Features and Benefits
• Excellent cycling capability
• Excellent DC performance
• Low arc voltage and low
energy let-through (I
2
t)
For product data sheets, visit www.cooperbussmann.com/datasheets/ulcsa
188
High Speed Fuses
British BS 88 — 240V: 6-900A
5641.8
26.2
17.7
19.1
12.7
7.1
9.7
Fig. 2: LET
473828
6.4
8.4
8.7
4
5.5
Dimensions (mm)
Fig. 1: LCT
1mm = 0.0394” / 1” = 25.4mm
LCT, LET, LMT, LMMT
Specifications
Description: BS 88 style
stud-mount fuses.
Dimensions: See dimensions
illustrations.
Ratings:
Volts: — 240Vac/150Vdc
Amps: — 6-900A
IR: — 200kA RMS Sym.
Agency Information: CE, Designed and tested to: BS 88
Part 4, IEC 269 Part 4, UL Recognized. All fuses above have
been tested at 318Vac. Consult Cooper Bussmann for
specific UL Recognition status.
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 characteristics. For
other voltages, the clearing
I
2
t is found by multiplying by
correction factor, K, given as
a function of applied working
voltage, E
g
, (rms).
845931
83
38
25.4
13.5
10.3
0.2
0.4
0.6
0.8
1.0
1.2
1.4
1.6
10050 150 200 250
1)
2)
E
g
K
845931
41
38.1
25.4
10.3
13.5
Fig. 3: LMT
Fig. 4: LMMT
Indicator (Optional)
1) LCT
2) LET, LMT, LMMT
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%
I
b
750
500
250
100 200 300
1)
2)
E
g
U
L
1) LCT
2) LET, LMT, LMMT
Typical Applications
• DC common bus
• AC and DC drives
• Power converters/rectifiers
• Reduced voltage starters
Data Sheet: 720004