FUSIBLE RESISTORS,FLAMEPROOF
1. Applicable Scope:
This standard specification is for use in consumer electronics, computers, telecommunications, control
instruments...etc.
2. Part Number:
It is composed by Type, Rated Wattage, Nominal Resistance, Tolerance and Package/Terminal Form . e.g.
2.1Type :
1W
10 Ω
J
T/B
FRN
Type Rated Wattage Nominal Resistance Tolerance
Package/Terminal Form
2.1Type :
Fusible resistors, Flameproof are called"FRN" or "FRL".
2.2 Rated Wattage:
Shown by
“W”,
such as 1/4W, 1/2W, 3/4W, 1W, 2W, 3W.
2.3 Nominal Resistance :
Ω,KΩ are its unit which be in accordance with JIS-C6409 article 6 (EIA RS-196A) series.
2.4 Tolerance:
It is measured by Bridge-method at room temperature and expressed by a capital letter.
F=± 1%; G=±2%; J=± 5%; K=±10%.
2.5 Package/Terminal Form:
T/B = tape in box; T/R= tape & reel; Nil＝Bulk; MG form, F forms.
※ Remark : FRL & FRN Series Resistors are RoHS Compliant.
3. Rated Power:
Rated power is the value of Max load wattage specified at the ambient temperature of 70℃, and shall meet
the functions of electrical and mechanical performance. When the ambient temperature surpasses above
mentioned temperature, the value declines as per following DERATING CURVE.
3.1 Rated Voltage:
It is calculated through the following formula:
where E: rated voltage (V)
P: rated power (W)
R: nominal resistance value (Ω)
E
=
P
*
R
However, in case the voltage calculated exceeds the maximum load voltage, such the maximum load
voltage shall be regarded as its rated voltage, means whichever less.
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4. Dimension and structure:
4.1 Dimension:
Unit: mm
TYPE
FRL
FRN
L±1
6.8
9
9
11
15
Dimension (mm)
D±1
2.6±0.5
3
3.5
4.5
5
H±3
28
28
28
28
28
d±0.1
0.6
0.65
0.65
0.8
0.8
Resistance Range
FRL
FRN
Max
Working
Voltage
250V
300V
Dielectric
Withstanding
Voltage
300V
350V
500V
500V
500V
1/4W 1/2W
3/4W
1/2W
1W
2W
1W
2W
3W
0.22Ω~10KΩ 0.22Ω~100KΩ
300V
350V
500V
Notes : 1. Too low or too high ohmic values can be supplied only case by case.
2. Max Overload Voltage is 2 times of Max Working Voltage.
3. UL approval : FRN 1/2W series
4.2 Structure:
4.2.1 Terminal:
Terminal is to be firmly connected with resistors element, both electrically and mechanically,
and allow easy soldering.
4.2.2 Coating:
Coating is done by light gray flameproof paint for FRL type and dark gray flameproof paint for
FRN (resistant to 800℃)which is solid enough to be free from looseness, crack and easy
breakage. It is also resistant to cleaning and industrial solvents, and the paint shall be limited
within 2mm of lead wires from resistor body.
4.2.3 Marking:
Marking is made on resistors surface by five colors coding.
1st,2nd,3rd: nominal resistance.
4th: tolerance.
5th:black for fusible resistors.
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5. Fusing Characteristics:
Fusing Power
Resistance Range
0.22Ω ~ 1Ω
1.1Ω ~ 2Ω
2.1Ω ~ 10Ω
10.1Ω ~ 10KΩ
10KΩ ~ 100KΩ
Note:■ Fusing time is within 60 sec.
■ The resistance value will be as high as
100 times the original value after fusing.
FRL
Rated Power X 32
Rated Power X 25
Rated Power X 16 Rated Power X16
Rated Power X 12
FRN
6. Operating Temperature Range: -55℃½155℃
7. Mechanical Performance
7.1 Terminal tensile:
To fix the resistor body, a static load of 2.5kgs.(under 1/2W : 1kg) is to be gradually applied into the
terminal for 10 seconds without causing any looseness and fall.
7.2 Twist withstand:
To bend the lead wire at the point of about 6mm from resistor body to 90°, then catch the wire at 1.2
±0.4mm apart from the bent point end and turn it (clockwise) by 360 degrees perpendicular to the
resistor axis at speed of 5 seconds per turn, and do the same counterclockwise again which constitute
a whole turn. Repeat the turn 2 times without causing any break and looseness.
8. Electrical Performance:
8.1 Resistance Temperature Coefficient:
It shall be within ±200ppm/℃.
T.C (ppm/℃) =［(R2－R1) ÷R1½ ×［1÷(T2－T1)½×10
6
where
R1: resistance value at reference temperature
R2: resistance value at test temp.
T1: reference temp. (usu. 25℃)
T2: test temp. (about 75℃)
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8.2 Temperature Cycle:
Following temp. cycles are to be made 5 times and then put at room temp. for one hour, the
resistance value change rate between pre-and-post test shall be within ±1%.
Steps
1
st
step
2
nd
step
3
rd
step
th
4 step
Temperature(℃)
-55
±
3
Room temp.
155
±
3
Room temp.
Time (minutes)
30
3
30
3
8.3 Short Time Over Load:
When the resistors are applied 4 times as much as rated wattage for 5 seconds continuously, it shows
no evidence of arc, flame...etc. Removing the voltage and place the resistors to the normal condition
for 30 minutes, the resistance value change rate between pre-and-post test shall be within
±2%.
8.4 Insulation Character :
Resistors are located in a V-shaped metal trough. Using the DC 500V megger instrument 2 poles to
clutch either side of lead wires and metal trough, measuring the Insulation Resistance which shall be
over 1000MΩ.
8.5 Voltage Withstanding:
Resistors are located in a V-shaped metal trough. Applying suitable voltage listed on DIMENSION
for one minute and should find no physical damage to the resistors, such as arc, char...etc.
8.6 Load Life:
The resistors arrayed are sent into the 70℃ oven, applying rated voltage at the cycle of 1.5 hours
ON, 0.5 hour OFF for 1000
+48
hours in total. Then, after removing the voltage, take the resistors out
-0
of the oven and left under normal temp. for one hour cooling. The resistance value change rate
between pre-and-post test shall be within ±5%.
8.7 Moisture-proof Load Life:
The resistors arrayed are placed into a constant temp./humidity oven at the temp. of 40 ±2℃ and the
humidity of 90½95%, then rated power is applied for 1.5 hours and cut off for 0.5 hour. The similar
cycle will be repeated for 1000
+48
hours in total (including cut-off time). Then remove the voltage,
-0
taking the resistors out of the oven and leaving them at room temp. for one hour. The resistance value
change rate between pre-and-post test shall be within ±5%. There also shall be no evidence of
remarkable change on appearance, and the marking shall not be illegible.
8.8 Solder-ability:
The leads with flux are dipped in a melted solder of 235 ±5℃ for 2 seconds, more than 95% of the
circumference of the lead wires shall be covered with solder.
8.9 Resistance to Soldering Heat:
Two leads are together dipped in a melted solder of 270 ±5℃ for 10 ±1 seconds, or 350 ±10℃ for
3.5 ±0.5 seconds,Then remove the resistors and leaving them at room temp. for one hour. The
resistance value change rate between pre-and-post test shall be within ±1%.
8.10 Nonflammability:
The resistors are applied the power of 16 times the rated wattage for 5 min. and shall not get flame.
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