MIL-PRF-19E
4.7.13 Switch life (see 3.18). A current of 3.0 ampere flowing through a carbon lamp or a wirewound resistor load
with an ac rms potential of 117 volts ±10 percent applied, applied at commercial line frequency and waveform of not
more than 100 hertz, shall be interrupted 15,000 times by the operation of the switch. Switch contact resistance shall
be measured both before and after the 15,000 cycles of on-off operation. At the conclusion of the test, resistors shall
be examined for evidence of damage. This test shall be conducted concurrently with the rotational life test specified
in 4.7.12.
4.7.14 Insulation resistance (see 3.19). Resistors shall be tested in accordance with method 302 of MlL-STD-202.
The following details shall apply:
a.
Test condition letter: A.
b.
Special preparation: Resistors shall be mounted on metal plates of sufficient size to extend beyond the
resistor extremities, and in such a manner that measurements can be made between the terminals tied
together and any other external metal parts.
c.
Points of measurements: Between the terminals connected together and all external metal portions of the
resistors and metal mounting plate.
4.7.15 Shock (specified pulse) (see 3.20). Resistors shall be tested in accordance with method 213 of
MIL-STD-202. The following details and exceptions shall apply:
a.
Mounting: Resistors shall be mounted by their normal mounting means and affixed on an appropriate
mounting fixture. A suggested mounting fixture shall be constructed in such a manner as to insure that the
mounting supports remain in a static condition with reference to the shock test table. Test leads used
during this test shall be as small a wire size as practicable (e.g., AWG 22 stranded) so the influence of the
test lead on the resistor will be held to a minimum The test lead length shall be no longer than necessary.
a manner that the stress applied is in the direction which would be considered most detrimental. The
contact arm shall be positioned at the approximate midpoint of the resistance element.
b.
Measurements after mounting: Total resistance shall be measured as specified in 4.7.3.1; the resistance
shall be measured between the contact arm terminal and terminal number one.
c.
Test condition: C.
d.
Motion: Resistors shall be subjected to a total of 20 impacts (five blows in each of two directions in each of
two mutually perpendicular planes). One of the test planes used shall be perpendicular and the other
parallel to the longitudinal axis of the operating shaft.
e.
Measurement during test: Each resistor shall be monitored to determine momentary discontinuity by a
method which shall at least be sensitive enough to monitor or register automatically any momentary
discontinuity of 0.1 millisecond or greater duration.
Measurements and examination after test: Total resistance shall be measured as specified in 4.7.3.1; the
f.
resistance shall also be measured between the contact arm terminal and terminal number one. Resistors
shall then be examined for evidence of mechanical damage.
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