MIL-PRF-39019 Circuit Breakers, Magnetic, Low-Power Sealed, Trip-Free General Specification ForThis specification covers the requirements and test procedures for single and multipole, trip-free, sealed, low-power, magnetic circuit breakers with current ratings of 0.050 amperes to 20.0 amperes inclusive, up to and including 240 volts, 60 hertz \(Hz\) and 400 Hz alternating current \(ac\), and 50 volts direct current \(dc\) \(see 6.1 and 6.7\). These circuit breakers may also include auxiliary contacts \(see 6.6.1\) and terminals for monitoring circuits. Designers are CAUTIONED 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-39019F

Examination after test: Examine for evidence of breaking, cracking, spalling, or loosening of terminals.

Tests after moisture resistance test: Circuit breakers shall be subjected to the following tests:

(1)

Dielectric withstanding voltage (see 4.8.3).

(2)

Calibration (see 4.8.6.2).

(3)

Seal (4.8.8).

(4)

Panel seal (see 4.8.9).

4.8.15 Thermal shock (see 3.18). Circuit breakers shall be tested in accordance with method 107 of

MIL-STD-202. The following details shall apply.

Mounting: Normal mounting means and in such a manner that there is at least 1 inch of free air space around

each circuit breaker.

Test condition: B.

Examination after cycling: Circuit breakers shall be examined for evidence of mechanical damage.

4.8.16 Shock (specified pulse) (see 3.19). Circuit breakers shall be tested in accordance with method 213 of

MIL-STD-202. The following details shall apply.

Mounting method: Normal mounting means.

Test condition: I.

Electrical load conditions and measurements: Of the three shocks in each direction required, two shocks shall

be performed with the circuit breaker energized at 100 percent of rated current at 12 volts dc, except that for

the directions with the operating lever pivot up (table mount) and the operating lever pivot down (ceiling

mount), no voltage or current shall be applied. Each energized shock shall be monitored to determine opening

of the main or auxiliary circuit breaker contacts. The remaining shock in each direction shall be performed with

the circuit breaker contacts open and unenergized and shall be monitored to determine closing of the main or

auxiliary contacts.

Examination after shock (see 3.19): Circuit breakers shall be examined for evidence of mechanical and

electrical damage.

4.8.17 Trip free calibration (see 3.20). The circuit breaker lever shall be physically held in the closed position and

the breaker subjected to the calibration test as specified in 4.8.6.1.