Circuit Breakers, Trip-Free, Aircraft General Specification for
|Publication Date:||1 August 1999|
The primary function of this specification is to cover the general requirements of one-, two-, and three-pole trip-free circuit breakers for use in aircraft electric systems conforming to MIL-STD-704. As a secondary function, this specification may possibly cover the general requirements of one-, two- and three-pole circuit breakers for use in primary vehicles, other than aircraft, when mounted directly to the structure.
Circuit breakers shall be classified into types and styles. Variations from the basic style of each circuit breaker shall be indicated by the part number from the appropriate specification sheet (see 3.1).
1.2.1 Types: Circuit breakers shall be of the following types as specified (see 6.2).
Type I--Thermal Type
Type II--Magnetic Type
1.2.2 Styles: A style of circuit breakers shall consist of all part numbers covered by one Military Standard (MS sheets). For example:
a. All part numbers of MS25244 shall be the same style.
b. All part numbers of MS22073 shall be the same style.
The same style classification applies to all MS sheets and specification sheets covered by this specification.
1.2.3 Part numbers: The part numbers for circuit breakers in accordance with this specification shall conform to the example below. Alpha numeric characters shall be used to designate variations from the basic style of each circuit breaker.
When a designator for a variation is not applicable it shall be omitted from the part number.
1.2.4 Amperage ratings: The amperage rating designator shall be a number specified in each detail specification to indicate the nominal amperage rating.
1.2.5 Pushbuttons: The circuit breakers pushbutton shall be designated as follows. Standard length pushbutton, as specified in the detail specification, shall have no designator letter.
L--Extra length pushbutton (see 6.4.9).
1.2.6 Auxiliary terminals: The use of auxiliary terminals when allowed by the MS or specification sheet shall be designated as follows. Circuit breakers with standard terminals only, as specified in the MS or specification sheet, shall have no designator letter.
1.2.7 Vibration level: The vibration level of the circuit breaker shall be specified in the MS or specification sheet and shall be indicated in the part number by one or more of the following designators. Standard sine vibration capabilities shall have no designator (see 220.127.116.11).
V--High Level sine capabilities (see 18.104.22.168).
C thru K--Random vibration capabilities (see 22.214.171.124).
1.2.8 Mounting configurations: Unless otherwise specified, the circuit breakers mounting configuration shall be designated as follows. Standard bushing mounted circuit breakers shall have no designator.