MIL-PRF-39019F
of 40 percent, tests of these particular overload levels shall be omitted with qualification activity approval. Each
section of multipole breakers shall be subjected to the calibration current specified, with remaining pole or poles
passing no current.
4.8.6.1.2 Time delay C. Circuit breakers shall be tested as specified in 4.8.6.1.1, except the circuit breakers shall
only be subjected to 100 percent, 135 percent, and 200 percent of rated current.
4.8.6.2 Method II (used for group A inspection, high-temperature and low-temperature operation, endurance,
moisture resistance, and interrupting capacity and trip-free calibration).
4.8.6.2.1 Time delay A and time delay B. Circuit breakers shall be tested as specified in 4.8.6.1.1, except the
circuit breakers shall be tested when mounted in the vertical plane and only 135 percent and 200 percent of rated
current shall be applied. The sample units shall be divided as evenly as possible (with respect to current rating and
time delay) into three groups for testing at the following current types and frequencies: dc, ac at 60Hz, and ac at
400Hz. The applied voltage shall be at a level sufficient to maintain the specified percent of rated current during
testing. Circuit breakers rated for high inrush shall be subjected to a half wave of the 60 Hz waveform or a half wave
of the 400 Hz waveform, (see 3.1).
4.8.6.2.2 Time delay C. Circuit breakers shall be tested as specified in 4.8.6.1.2, except the circuit breakers shall
be tested when mounted in the vertical plane only and shall only be subjected to 135 percent and 200 percent of
rated current.
4.8.7 Actuating lever (see 3.10).
4.8.7.1 Lever strength (see 3.10.1). Circuit breakers shall have a 10-pound load applied to the tip of the actuating
lever for 1 minute under each of the following conditions:
a.
Normal to the lever axis in the plane of lever travel at each extreme position of the lever.
b.
Normal to the lever axis and normal to the plane of lever travel at each extreme position of the lever.
c.
Coaxial with the lever axis toward the lever pivot throughout the entire range of lever travel.
d.
Coaxial with the lever axis away from the lever pivot throughout the entire range of lever travel.
Circuit breakers shall be examined for evidence of mechanical damage.
4.8.7.2 Lever operating force (see 3.10.2). The force necessary to operate the actuating lever shall be applied in
both operating directions at the rounded tip of the lever. The force shall be applied normal to the lever axis and in the
plane of lever travel. The magnitude of the force required to operate the lever shall be determined.
4.8.8 Seal (see 3.11).
4.8.8.1 Seal (used for qualification and retention of qualification) (see 3.11). Circuit breakers shall be immersed to
a depth not exceeding 10 inches in tap water which may contain a wetting agent. The absolute pressure of the air
above the water shall then be reduced to 2.5 inches of mercury and maintained for 1 minute or until air bubbles cease
to flow, whichever is longer. During immersion, observation shall be made for any visible air bubbles indicative of
leakage emanating from the circuit breakers, either in the form of continuous stream or as bubbles emanating at
regular intervals. Bubbles which are determined to be the result of entrapped air on the exterior parts of the
immersed circuit breakers shall not be considered a leak.
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