MIL-DTL-17361G(SH)
4.5.14 Shock.
4.5.14.1 Circuit breaker samples, states, and mounting. Circuit breakers on mounting bases/blocks, with
attachments, including current limiting fuse units, shall be tested in both the open and closed position in accordance
with the high impact shock tests specified in MIL-S-901 for Grade A, Class I, Type C equipment. One sample unit
shall be used for testing the entire open and closed condition circuit breaker test series. Multiple sample units to
shock test the circuit breaker in the open position and one sample unit to test in the closed position shall not be
allowed. Unless otherwise specified (see 3.1), mounting for shock testing AQB circuit breakers shall be in
accordance with Figure 4. Where a two circuit breaker mounting base/block or assembly is also involved, it shall be
tested for mechanical damage by mounting in a horizontal position on the top supporting channel shown on Figure 4
and two circuit breakers shall be used as dummy weights. Where current limiting fuse units are involved, they shall
be included.
4.5.14.2 Equipment energization.
4.5.14.2.1 Circuit breakers.
4.5.14.2.1.1 Thermal magnetic. Thermal magnetic circuit breakers with or without fuse units shall be
energized during the test with a 12-volt or less source and current equivalent to 30 to 50 percent of the breakers full-
load current.
4.5.14.2.1.2 Electronic. Electronic trip device type circuit breakers with or without fuse units shall be
energized with a 12-volt or less source at any convenient current.
4.5.14.2.2 Attachments.
4.5.14.2.2.1 Undervoltage releases. Undervoltage releases shall be energized at nominal voltage of operating
range.
4.5.14.2.2.2 Auxiliary switch. Auxiliary switches shall be energized with at least 5 volts in order to clearly
determine bounce and chatter during shock.
4.5.14.2.2.3 Electric operating mechanism. Electric operating mechanisms shall be energized with rated
voltage at their common terminals in order to detect mal-operation of mechanism controls (relays, limit switches,
etc.) that may cause the circuit breaker to change state.
4.5.14.3 Monitoring of main and auxiliary contacts.
4.5.14.3.1 Monitoring equipment. Main and auxiliary contacts shall be monitored by oscillograph, FM tape
recorder, or suitable digital data acquisition system. All equipment shall have a minimum frequency response and
sampling rate of 2 KHz. Digital signal processing of acquired data shall be capable of producing suitable waveform
plots with 0.5 millisecond minimum resolution, and for analysis purposes shall be able to expand contact events with
graphical editing to determine time increments of the individual sample points.
4.5.14.3.2 Number of contacts to monitor. Main contacts on each phase shall be monitored during each shock
blow. For auxiliary contacts, one "a" contact (normally closed) and one "b" contact (normally open) shall be
monitored during each shock blow.
4.5.14.4 Pass/fail criteria.
4.5.14.4.1 Pass/fail criteria during shock. The circuit breaker shall meet the following criteria during shock
testing:
a. Circuit breakers shall not change position/state from "on" to "off" or from "off" to "on" during the test. An
"off" to "trip" position/state change is permitted.
b.
Main and auxiliary contacts shall not close when open.
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