MIL-PRF-19500/297H
4.4.4 Group E inspection. Group E inspection shall be conducted in accordance with the conditions specified for
subgroup testing in appendix E, table E-IX of MIL-PRF-19500, and table II herein. Electrical measurements (end-
points) shall be in accordance with table I, subgroup 2 herein. Delta measurements shall be in accordance with table
III herein.
4.5 Methods of inspection. Methods of inspection shall be as specified in the appropriate tables and as follows.
4.5.1 DC intermittent operation life. A cycle shall consist of an on period, when power is applied suddenly, not
gradually, to the device for the time necessary to achieve a delta case temperature of 85°C +15°C -5°C followed by
an off period, when the power is suddenly removed, for cooling. Auxiliary (forced) cooling is permitted during the off
period only. 30 s < tHeating < 60 s, P = VF x IF or P = VFPK x Iav if using sine wave current. DC full wave current (or
equivalent half sine wave current) shall be used for the power required during the on period. The test power, or
current, shall be at least the free air rating. Within the time interval of 50 cycles before to 500 cycles after the
termination of the test, the sample units shall be removed from the specified test conditions and allowed to reach
room ambient conditions. Specified end-point measurements for qualification and verification shall be completed
within 96 hours after removal of sample units from the specified test conditions. Additional readings may be taken at
the discretion of the manufacturer.
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