TM
FUSIBLE RESISTORS
CERAMIC TYPES
Flame Proof
High Temperature
Ceramic Housing
Inorganic
Fire Retardant
Encapsulant
SERIES
FUSIBLE RESISTORS
Ceramic Encased Bath Tub Type With
Flame Retardant Moulding.
FRC
Mechanically Crimped
Termination Assembly
Alloy Wire Wound
Element On
Fibre Glass/Ceramic
Substrate
In order to meet the growing demand worldwide for resistors
to fuse or blow as a safety measure, HTR can provide fusible
resistor which fuse or blow if they are subjected to an abnormal
spike of voltage / current.
PHYSICAL CONFIGURATIONS
d
HTR
TYPE
35+3
L
35+3
POWER
RATING
at 70°C
1W
1W
2W
3W
DIMENSIONS (mm)
L
+1.5
W
+1
5.5
7.5
7.5
8.0
RESISTANCE TYPICAL
RANGE
WT.
PER PC
d
H
+1 +0.05
min
max (gms)
0.8
0.8
0.8
0.8
10R 750R
10R 750R
10R 1K5
10R 2K2
1.4
1.9
2.5
3.8
H
C-1AF
C-1F
C-2F
C-3F
13.0
15.0
17.5
22.0
5.5
6.5
7.0
8.0
W
Resistance values below the minimum range can be supplied on request.
ELECTRICAL AND ENVIRONMENTAL CHARACTERISTICS / DATA
Test
Resistance tolerance
Dielectric withstanding voltage
Insulation resistance
Temperature co-efficient
Short time overload
Moisture resistance
Load life
Ambient operating
temperature range
Flame test
Performance requirements
+ 10% [K]; + 5% [J]
Max.
D
R + [2% + R05]
>1000 M [Dry]
+ 550 ppm/ °C
Max.
D
R + [2% + R05]
Max.
D
R + [5% + R05]
Max.
D
R + [5% + R05]
-40°C to +155°C
Specifications laid down by
UL have been met satisfactorily
NOTE :
Contrary to popular belief, fusible resistors
are not standard resistor types and each type
of fusible resistor must be tailor designed to
suit a particular application.
TM
FUSIBLE RESISTORS
CERAMIC TYPES
FRC
TYPICAL APPLICATIONS
As mentioned previously a fusible resistor is a tailor made dual purpose component -
(a) In normal conditions it functions as a resistor.
(b) In high overload conditions it acts as a fuse/safety device.
In some countries all types of ceramic encased / bath tub type resistors are wrongly called as fusible resistors.
It must be clearly understood that fusible resistors are special purpose, specially designed resistors and are
produced mainly in two configurations -
(a) Ceramic encased bath - tub type and
(b) Flame retardant silicone coated type. (Refer FRS series).
ORDERING INFORMATION
In order to design a fusible ceramic encased resistor suitable for your needs, we need the following data :-
Power rating in terms of watts.
Resistance in ohms.
Tolerance.
Maximum continuous working voltage across the resistor, at which the resistor must continue to function.
Fusing voltage - The voltage at which the resistor must fuse or blow.
Fusing time - The duration within which the resistor must fuse or blow on being subjected to the fusing
voltage.
7) In case lead preforming is required, we need a drawing. This service is provided upon a minimum order of
5000 pieces.
Note :
Generally speaking as per international standards, a fusible resistor fuses
on being given fusing voltage from instantaneously to 45 seconds without
any flame.
At HTR if no special data is provided, we assume that if a fusible resistor is
ordered, it should fuse on being given voltage calculated at 16 times
power from instantaneously to 45 seconds.
For resistance values<10R the fusing timing and suitability must be tested
for each individual application.
Precautions to be taken
:
Before conducting this test the voltage must be correctly set / adjusted
by first using a dummy piece which should then be discarded.
1)
2)
3)
4)
5)
6)
ORDERING INFORMATION
FRC
C2F
47R
J
TOLERANCE
RESISTANCE VALUE
HTR TYPE
SERIES
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