MIL-DTL-17587C(SH)
4.5.5.1.3.2 Anti-rolling verification. With a 25-pound force applied to the front of the circuit breaker in the
horizontal direction towards the cradle backplane, the following criteria shall be met. The force shall be applied as
close to the center of the circuit breaker as possible. An instrument or device shall be used to measure and verify
that a 25-pound force is applied.
a. The circuit breaker shall not move in and out on the cradle rails/tray.
b. The circuit breaker shall not fall off the cradle rails/tray.
c. No part of the circuit breaker shall come off the cradle rails/tray in such a manner as to require manual
repositioning of the circuit breaker.
4.5.5.1.3.3 Cradle strength test. A weight equal to 50 percent of the circuit breaker weight shall be added with
the circuit breaker in the withdrawn position on the cradle rails/tray. A dummy weight equal to the size and weight
of the circuit breaker can be used instead of an actual breaker. One-half the additional weight shall be attached on
the left and right sides of the cradle as follows:
a. With weight hanging straight down, attach 25 percent of the additional weight to the right side cradle rail or
bottom right side of cradle tray with a rope or cable at no more than ¼ the depth of the circuit breaker measuring
from the front of the circuit breaker.
b. With weight hanging straight down, attach 25 percent of the additional weight to the left side cradle rail or
bottom left side of cradle tray with a rope or cable at no more than ¼ the depth of the circuit breaker measuring from
the front of the circuit breaker.
The circuit breaker and additional weight shall remain on the cradle rails/tray in the withdrawn position for 10
minutes. During that time period, there shall be no collapse or failure of the cradle. After the 10-minute period, the
weight shall be removed and the circuit breaker shall be fully racked in and racked out to the withdrawn position
without any failure.
4.5.5.2 Rack-in. With the circuit breaker in the withdrawn position and closed, the circuit breaker shall then be
racked-in to the disconnect, test, and connect positions and meet the criteria of 4.5.5.2.1, 4.5.5.2.2, and 4.5.5.2.3.
4.5.5.2.1 Disconnect position. The criteria of 4.5.5.1.2 shall be met except that the withdrawal interlock
mechanism operation shall be checked in the test position per 4.5.5.2.2.
4.5.5.2.2 Test position. The criteria of 4.5.5.1.1 shall be met except that it shall be verified that the withdrawal
interlock mechanism opens the circuit breaker main contacts as the circuit breaker is racked in to the test position.
4.5.5.2.3 Connect position.
4.5.5.2.3.1 Main contact energization and rack-in/rack-out position indicator operation. Verify by
measurement that the main contacts are energized and visually verify that the rack-in/rack-out position indicator is
in the "connect" position.
4.5.5.2.3.2 Cell switch operation. The cell switch shall be verified by measurement to be in the open position.
4.5.6 Endurance.
4.5.6.1 Circuit breakers. Circuit breakers shall be subjected to the endurance tests of 4.5.6.1.1 and 4.5.6.1.2
without failure or operating irregularities. At the completion of each endurance test, the circuit breakers shall be
closely examined to identify any evidence of undue wear or development of operating irregularities in any part.
4.5.6.1.1 Mechanical endurance test.
4.5.6.1.1.1 Test setup and method of cycling. No power shall be applied to the circuit breaker primary studs
and close-open operation shall be accomplished by the manual operating mechanism on all circuit breakers.
4.5.6.1.1.2 Number and rate of operations. Circuit breakers shall be operated at any convenient speed of
operation for the number of close-open cycles specified in the applicable specification sheet.
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