MIL-PRF-55629 Circuit Breakers, Magnetic, Unsealed Or Panel Seal, Trip-Free, General Specification ForThis specification covers the requirements and test procedures for single and multipole, trip-free, unsealed, magnetic circuit breakers with current ratings of 0.2 amperes to 100 amperes inclusive, up to and including 240 volts, 400 Hertz, 480 volts, 60 Hertz alternating current \(ac\) and 125 volts direct current \(dc\), \(see 6.1\). These circuit breakers may also include auxiliary contacts \(see 6.6.1\) for monitoring circuits. A voltage sensitive pole is also available in a four pole device. Panel seal mounts are available in 0.2 amperes through 50 amperes. Designers are WARNED that these circuit breakers may contain a pure tin finish on some of the component parts \(see 6.5\).

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MIL-PRF-55629E

LEGEND

S - SUPPLY

V - VOLTMETER

A - RECORDING CURRENT

ELEMENT

R - RESISTORS LIMITING

CURRENT TO SPECIFIED

VALUES

C - TEST CIRCUIT BREAKER

M - MOUNTING PLATE

F - 30 AMPERE FUSE

"O"-"CO"-"O" OPERATIONS

I-POLE CIRCUIT BREAKER TEST

NOTES:

1. "O" - Circuit breaker is closed, then fault initiated.

2. "CO" - Circuit breaker closed into existing fault.

3. Interrupting current shall be measured by a current transformer or shunt "A" and suitable recording

oscillograph. The voltage across the breaker shall be recorded simultaneously with rupture current. (not

shown)

4. For test circuit calibration see 4.8.19.

FIGURE 3. AC interrupting capacity test operations (duty cycle) and circuit wiring.