Medium Voltage Fuses
Medium Voltage Fuses
2,400 - 38,000 VAC • Current-Limiting
Current-limiting “E” and “R” rated fuses
are equipped with a mechanical indicator
or striker pin that protrudes through the
fuse cap upon operation of the fuse. This
provides visual identification of a blown
fuse and can be used as a trigger for
external devices.
Note: Extension distance
1
/
2
” min; extension
force 2lb. min
General Information
The terms “Medium Voltage” and “High Voltage” have been used
interchangeably by many people to describe fuses operating above 600
volts. Technically speaking, “medium voltage” fuses are those intended
for the voltage range from 2,400 to 38,000 VAC. “High voltage” fuses
are for circuits carrying voltages greater than 38,000 VAC.
“E” rated fuses are considered to be general purpose fuses and can be
used to protect against low and high values of fault current. “R” rated
fuses are designed for back-up protection. They must be used in series
with other devices such as motor overload relays in order to achieve
both overload and short-circuit protection.
Medium voltage fuses are not intended to provide overload protection in
the same sense as fuses rated 600 volts or less. Medium voltage fuse
current ratings do not have the same meanings as the ampere ratings of
low voltage fuses.
Littelfuse now offers a complete selection of “E” and “R” rated
medium voltage fuses for the protection of transformers, potential
transformers, feeders, and motor circuits. Single, double, and triple
barrel designs are available to cover a wide range of current, voltage,
and interrupting ratings. Conventional ferrule type, clip lock, and bolt-in
mounting configurations are now available for virtually any application.
Hermetically sealed fuses for use in hazardous environments are also
offered.
Contact the factory or your local Littelfuse representative for additional
fuse ratings or custom mounting configurations.
24 Hour Emergency Service is available. Call 847 824 1188.
All medium voltage fuses are limited in their ability to interrupt low value
overcurrents, especially those between 100% and 200% of the fuse’s
continuous current rating. They are designed to carry their rated current
without exceeding the temperature rise permitted by NEMA and ANSI
standards.
Additional application data can be found in the Fuse Application section
of this catalog.
Medium Voltage Fuses
Applications
Power Transformer Protection
Potential Transformer Protection
Motor Controller Back-up Protection
Fused Switches
Feeder Circuits
Bolt-in Mount Fuses
64
www.littelfuse.com
© 2005 Littelfuse
•
POWR-GARD
™
Products Catalog
Medium Voltage Fuses
R Rated Medium Voltage Fuses
Current-Limiting
Features
“R” rated fuses provide required short-circuit protection for medium
voltage motors, motor controllers and associated circuitry. These
components have limited ability to absorb the energy of large short-
circuit currents. Medium voltage motor controllers contain overload
relays which provide both overload protection and locked rotor
protection to the motor. The controllers are also intended to interrupt
low value short-circuits within the capability of the motor controller. This
protects the medium voltage fuse from sustained overcurrents which
are less than their minimum interrupting rating.
NEMA Standards for “R” rated medium voltage power fuses require
they operate within 15-35 seconds when subjected to an rms current
100 times the “R” rating. For example, a fuse with a 2R rating will open
within 15 to 35 seconds on an applied current of 2 x 100 = 200 amperes.
Characteristics
Voltage Rating:
Current Range:
2,400 volts – 8,250 volts
2R – 36R
Options
• Hermitically sealed for use in hazardous locations
(add “S” suffix to part number)
• Bolt-in mounting configurations
Hookeye Feature*
*For hookeye attach-
ment; add “W” suffix
to part number
Medium Voltage Fuses
Part Number System
130-4R-1C-5.5
Max Voltage (KV)
Style (C-Cartridge)
No. of Barrels
Rating (size)
Continuous Current
3"DIA
6.38"
9.75"
Dim.A
Clip
Center
Dim.B
Figure 1
D
Figure 2
Maximum
Dim. A
Continuous Current
A
(inches)
@ 40 deg C.
70
100
130
150
170
200
230
390
450
7"
7"
7"
7"
7"
7"
7"
7"
7"
DD
Figure 3
DDD
R
Rated
Catalog
Number
70-2R-1C-2.75
100-3R-1C-2.75
130-4R-1C-2.75
150-5R-1C-2.75
170-6R-1C-2.75
200-9R-1C-2.75
230-12R-1C-2.75
390-18R-2C-2.75
450-24R-2C-2.75
Old
Catalog
Number
LCK 2R
LCK 3R
LCK 4R
LCK 5R
LCK 6R
LCK 9R
LCK 12R
LCK 18R
LCK 24R
Size
2R
3R
4R
5R
6R
9R
12R
18R
24R
Dim. B Min. Interrupting Max Interrupting Figure
(inches) Rating RMS Amps Rating RMS Asym Number
10.875"
10.875"
10.875"
10.875"
10.875"
10.875"
10.875"
10.875"
10.875"
170
250
340
390
500
760
1000
1500
1950
80,000
80,000
80,000
80,000
80,000
80,000
80,000
80,000
80,000
1
1
1
1
1
1
1
2
2
Add “w” suffix to part number for hookeye attachment.
© 2005 Littelfuse
•
POWR-GARD
™
Products Catalog
2.75 KV
www.littelfuse.com
65
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