MIL-DTL-917F(SH)
(4) For all testing, voltage shall not be applied or removed at other than zero voltage.
b.
Nature of test voltage. The test voltage shall approximate a true sine wave of a frequency of 60 Hz.
c. Points of application. The test voltage shall be applied successively between each electrically isolated
circuit and ground with all other circuits grounded (see 4.4.2.1). The test voltage should be applied between
stationary and rotating windings of rotating equipment when the equipment is at a standstill.
d. Duration of test. The duration of the test shall be not less than 60 seconds. The test voltage shall be
removed by adjustment of its value to zero, not by sudden interruption.
e. Definition of failure. Any evidence of arcing, flashover, odor, or punctured insulation shall be interpreted
as a failure. Tripping of the test equipment shall also constitute failure.
Dielectric withstanding voltage tests shall be conducted after all other equipment tests have been completed or
as otherwise specified in the equipment specification (see 6.2).
4.4.2 Insulation resistance tests. Insulation resistance tests shall be conducted in accordance with Method 302
of MIL-STD-202 as specified (see 6.2). Test conditions shall be as follows:
a. Test potential. Test condition "B" (500 V ±10 percent). For test voltages 4,160 to 13,800 V, refer to
MIL-STD-1399-680 for test voltage, conditions, and guidance.
b. Points of measure. Between each electrically isolated circuit and all other circuits connected together to
ground [frame, chassis, or enclosure as applicable (see 4.4.2.1)].
c. Electrification time. Sixty seconds minimum for insulation suitability test and only sufficient time to take
resistance readings for all other tests.
d. Temperature at time of test. Temperature of parts to be tested shall be measured and recorded. Insulation
resistance measurements shall be corrected to 77 °F (25 °C). Correction shall be made on the basis of insulation
resistance doubling for each 18 °F (10 °C) decrease in temperature (good approximation). An alternate method for
temperature correction is to perform the test and calculate the change in resistance of the conductor insulation in
accordance with UL 2556.
4.4.2.1 Electrically isolated circuits. Electrically isolated circuits shall be determined by application of the
following criteria:
a. Circuits whose only connection to each other is by electromagnetic coupling through a magnetic core,
which is shared in common by the circuits, shall be considered to be electrically isolated from each other.
b. Circuits whose only connection to each other is through a capacitor shall not be considered to be
electrically isolated from each other. When the purpose is to test the insulation resistance of circuits internal to the
equipment, and only then, such circuits shall be temporarily interconnected with a jumper wire, or test load.
4.4.2.2 Moisture resistance. When specified (see 6.2), the insulation system to be used shall be tested to
determine moisture resistance (insulation suitability) as specified in Appendix A.
4.4.2.3 Arc and tracking resistance. Arc resistance tests shall be conducted in accordance with ASTM D2303
or IPC-TM-650 depending on the materials application. Tracking resistance shall be determined in accordance with
ASTM D3638 (see 3.4.1.1).
4.4.3 Leakage current test. Testing for leakage current through a human body simulated impedance shall be in
accordance with MIL-STD-1399-300.
4.4.4 Reliability and maintainability assurance.
4.4.4.1 Reliability demonstration tests. Reliability demonstration tests shall consist of performing the
reliability tests required by the individual equipment specification or acquisition document as specified (see 3.1 and
4.4.4.2 Maintainability demonstration tests. Maintainability demonstration tests shall consist of performing the
maintainability demonstration tests required by the individual equipment specification or acquisition document as
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