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2.1 Type : |
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Metal Glaze High Voltage Resistors are called "RT". |
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2.2 Rated Wattage: |
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Shown by "W", such as 1/4W,1/2W, 1W, 2W. |
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2.3 Terminal Form : |
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Upon the shape of terminal, there are "axial"
form o "F" forms and "MG" form. |
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2.4 Nominal Resistance : |
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K 
2,M are its unit,which
be in accordance with JIS-C6409 article 6 (EIA RS-196A) series. |
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2.5 Tolerance : |
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It is measured by Bridge-method at room temperature
and expressed bv a capital letter, F=
1%,J= 5%. |
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2.6 Package: |
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T/R=tape & reel; T/B = tape in box; Bulk. |
| 3. |
Rated Power : |
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Rated power is the value of Max load voltage specified
at the ambient temperature of 70oC, 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. |
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3.1 Rated Voltage: |
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It is calculated through the following formula: |
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where |
E: rated voltage (V) |
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P: rated power (W) |
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R: nominal resistance value () |
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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. |
| 4. |
Dimension and structure |
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4.1 Dimension: |
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4.2 Structure |
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4.2.1 Ceramic Rod: |
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It is made of Forste imported from Japan. |
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4.2.2 Terminal: |
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Terminal is to be firmly connected with resistors element, both
electrically and mechanically, and allow easy soldering. |
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4.2.3 Coating: |
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Coating is done by light blue flameproof paint for 1W,2W type and
light green epoxy paint for 1/4W, 1/2W type 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. |
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4.2.4 Marking: |
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Marking is made on resistors surface, by color coding. |
| 5. |
Operating Temperature Range:
-65oC ~ 175oC |
| 6. |
Mechanical Performance |
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6.1 Terminal tensile: |
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To fix the resistor body.a static load of 2.5kgs, (under
1 /2W:1 kg.) is to be gradually applied into the terminal for 10 seconds
without causing any looseness and fall. |
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6.2 Twist withstand: |
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To bend the lead wire at the point of about 6mm from
resistor body to 90o , then catch the wire at 1.20.4mm
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 eounterclockwise again which constitute a whole turn.
Repeat the turn 2 times without causing any break and looseness. |
| 7. |
Electrical Performance |
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7.1 Resistance Temperature
Coefficient: |
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It shall be within
200ppm/oC. |
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T.C(ppm/oC)= [(R2-R1) R1]
x [1(T2-T1)] x
106 |
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| where |
R1: resistance value at reference temperature |
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R2: resistance value at test temp. |
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T1- reference temp. (usu, 25oC) |
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T2: test temp. (about 75oC) |
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7.2 Short Time Over Load: |
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When the resistors are applied 2.5 times as much as
rated voltage 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 1%. |
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7.3 Insulation Character : |
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Resistors are located In a V-shaped metal trough. Using
the DC500V megger Instrument 2 poles to clutch either side of lead
wires and metal trough, measuring the Insulation Resistance which
shall be over 1000MO. |
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7.4 Voltage Withstanding : |
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Resistors are located in a V-shaped metal trough. Applying
Max Working Voltage for one minute and should find no physical damage
to the resistors, such as arc. char ...etc. |
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7.5 Load Life: |
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The resistors arrayed are sent into the 7oC.
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 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 3%. |
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7.6 Moisture-proof Load Life
: |
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The resistors arrayed are placed into a constant temp.
humidity oven at the temp. of 40
2oC and the humidity of 90~95%, then rated power is applied
for 1.5 hours and cut off for 0-5 hour. The similar cycle will be
repeated for 500+24 hours in total (including cut-off
time). Then remove the voltage, 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 3%.
There also shall be no evidence of remarkable change on appearance,
and the marking shall not be illegible. |
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7.7 Solderability : |
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The leads with flux are dipped in a melted solder of
235+ 5oC for 2 seconds, more than 95% of the circumference
of the lead wires shall be covered with solder. |
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7.8 Incombustibility (only
for 1W, 2W): |
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The resistors are applied the power of 16 times the
rated wattage for 5 min. and shall not get flame. |
