MIL-DTL-3950J
4.8.11.7 Temperature rise. Each pole(s) of the switch shall be connected in a circuit carrying the
resistive endurance test current at any convenient ac or dc voltage. At the end of a 1-hour period, the
terminal temperature rise at a point adjacent to the insulating medium shall be determined by means of
appropriate thermocouples consisting of No. 28-32 AWG iron-constantan wire. This test shall be
performed on the same switch contacts previously subjected to the overload and resistive electrical
endurance test. During the test, switches shall be mounted 6 inches apart in still air on 1/16 inch-thick
steel panel at least 6 inches long.
4.8.12 Short circuit (see 3.6.11). Switches shall be tested in accordance with 4.8.12.1, or 4.8.12.2
when specified (see 3.1). The following details shall apply to both methods:
a. The switches shall be inserted in a circuit calibrated to supply current equal to 60 times the rated
resistive load at the lowest rated dc voltage specified (see 3.1).
b. The switches shall be connected in series to a thermal type circuit breaker or a fuse in
c.
load of the switch (see 3.1).
d. Terminals shall be in accordance with SAE-AS7928.
e. Calibration shall be made with a substitute circuit breaker (or fuse), without the switch being
tested, and with the switch leads in the circuit.
f.
after the circuit breaker or fuse interrupts the circuit the appropriate switch shall be manually
opened by means of the toggle lever. This procedure shall be performed 10 times. After each
closure, the toggle lever of the switch under test shall be returned manually to the "OFF" or an
alternate position, and the switch contacts shall be checked for proper opening by any suitable
continuity test method. The circuit breaker shall be reset or the fuse replaced after each closure.
A minimum of two minutes shall elapse between closures. For double throw switches, one-half
shall be tested in one position, and the other half shall be tested in the other position. For
multipole switches any (one) pole shall be tested.
4.8.12.1 Method I. The switch used to calibrate the circuit shall close the circuit.
4.8.12.2 Method II. The switch being tested shall close the circuit.
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