MIL-PRF-49465C
Measurement after shock: DC resistance shall be measured as specified in 4.8.2.
f.
g.
Examination after test: Resistors shall be examined for evidence of mechanical and electrical damage.
4.8.14 Vibration, high frequency (see 3.20). Resistors shall be tested in accordance with method 204 of
MIL-STD-202. The following details and exceptions shall apply:
a.
Mounting of specimens: Resistors shall be mounted on appropriate jig fixtures with their bodies restrained
from movement and their leads supported at a distance of .375 ±.062 inch from the resistor body. These
fixtures shall be constructed in a manner to insure that the points of the resistor mounting supports will have
the same motion as the vibration within the test frequency range, and the fixture shall be monitored for these
features on the vibration table. Test leads used during this test shall be no larger than AWG size 22
stranded wire, so that the influence of the test lead on the resistor will be held to a minimum. The test cable
which may be necessary because of the field surrounding the vibration table, shall be clamped to the
resistor mounting jig.
Initial measurement: DC resistance shall be measured as specified in 4.8.2.
b.
c.
Test condition: D.
d.
Direction of motion: In each of two mutually perpendicular directions, one perpendicular and the other
parallel to the longitudinal axis of the resistor. Total test time shall be 6 hours in each direction for a total of
12 hours.
e.
Measurement during test: Each resistor shall be monitored to determine electrical discontinuity by a method
which shall at least be sensitive enough to monitor or register, automatically, any electrical discontinuity of
0.1 millisecond or greater duration.
f.
Measurement after vibration: DC resistance shall be measured as specified in 4.8.2.
g.
Examination after test: Resistors shall be examined for evidence of mechanical damage.
4.8.15 Life (see 3.21). Resistors shall be tested in accordance with method 108 of MIL-STD-202. The following
details and exceptions shall apply:
a.
Method of mounting: Resistors shall be mounted on lightweight terminals. The integrity of the terminations
shall be determined at each measurement interval. The voltage applied to any resistor shall not be less than
95 percent of the dc, ac line or true rms rated continuous working voltage. Resistors shall be so arranged
that the temperature of any one resistor shall not appreciably influence the temperature of any other resistor.
If forced air circulation is employed, the air velocity shall not exceed 500 feet per minute, and there shall be
no direct impingement of the forced air supply on the resistors.
Test temperature: +25OC ±5OC.
b.
Initial measurements: Initial resistance shall be measured after mounting at +25OC ±5OC. This initial
c.
measurement shall be used as the reference temperature for all measurements.
d.
Operating conditions: Resistors shall be operated at full rated wattage by applying dc continuous working
voltage, or ac rated continuous working voltage from an ac supply at commercial line frequency,
intermittently, 1 hour 30 minutes "on" and 30 minutes "off" for the applicable number of hours (see 4.8.15f).
"On time" shall be three fourths of the total elapsed time, the actual test time shall be recorded. Where
resulting waveform is other than that of a commercial line, voltages shall be set using a "true rms" voltmeter,
and the peak voltage shall not exceed 2.5 times the rated continuous working voltage.
e.
Test condition: 2,000 hours for all samples.
18
For Parts Inquires call Parts Hangar, Inc (727) 493-0744
© Copyright 2015 Integrated Publishing, Inc.
A Service Disabled Veteran Owned Small Business