1、 AMSC N/A FSC 5925 INCH-POUND MIL-DTL-27715B09 May 2008 SUPERSEDING MIL-DTL-27715A 05 April 2001 DETAIL SPECIFICATION CIRCUIT BREAKER, TRIP-FREE, HIGH TEMPERATURE, AIRCRAFT GENERAL SPECIFICATION FOR This specification is approved for use by all Departments and Agencies of the Department of Defense.
2、1. SCOPE 1.1 Scope. This specification covers the general requirements of push-pull type single pole, trip-free circuit breakers for use in protecting circuits with a rating of 118/200 volts at 400 Hz alternating current and 28 volts direct current, in ambient temperatures to 121.1C (250F). 1.2 Part
3、 or Identifying Number (PIN). The PIN will consist of the following (see 3.1 for details): MS24571-2V MS number dash number 2. APPLICABLE DOCUMENTS 2.1 General. The documents listed in this section are specified in sections 3, 4 or 5 of this specification. This section does not include documents cit
4、ed in other sections of this specification or recommended for additional information or as examples. While every effort has been made to ensure the completeness of this list, document users are cautioned that they must meet all specified requirements of documents cited in sections 3, 4 or 5 of this
5、specification, whether or not they are listed. 2.2 Government documents. 2.2.1 Specifications, standards, and handbooks. The following specifications, standards, and handbooks form a part of this document to the extent specified herein. Unless otherwise specified, the issues of these documents are t
6、hose cited in the solicitation or contract (see 6 2). DEPARTMENT OF DEFENSE SPECIFICATIONS MIL-S-7742 - Screw Threads, Standard, Optimum Selected Series: General Specification for. MIL-I-24768/1 - Insulation, Plastic, Laminated, Thermosetting, Glass Cloth, Melamine-Resin (GME). MIL-I-24768/17 - Insu
7、lation, Plastic, Laminated, Thermosetting, Glass Cloth, Silicone Resin (GSG). Comments, suggestions, or questions on this document should be addressed to: Defense Supply Center, Columbus, ATTN: DSCC-VAT, Post Office Box 3990, Columbus, Ohio 43218-3990 or by email CircuitProtectdla.mil. Since contact
8、 information can change, you may want to verify the currency of this address information using the ASSIST Online database at http:/assist.daps.dla.mil. Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-MIL-DTL-27715B 2 MS24571 - Circuit Breakers, Aircr
9、aft,Trip-free, 2 to 50 Amperes, 121.1C Ambient. MIL-DTL-31000 - Technical Data Packages. DEPARTMENT OF DEFENSE STANDARDS MIL-STD-130 - Identification Marking of U. S. Military Property. MIL-STD-202 - Test Method Standard, Electronic and Electrical Component Parts. MIL-STD-704 - Electric Power, Aircr
10、aft, Characteristics and Utilization Of. MIL-STD-810 - Environmental Engineering Considerations and Laboratory Tests. (Copies of these documents are available online at http:/assist.daps.dla.mil/quicksearch/ or http:/assist.daps.dla.mil or from the Standardization Document Order Desk, 700 Robbins Av
11、enue, Building 4D, Philadelphia, PA 19111-5094). 2.3 Non-Government publications. The following documents form a part of this document to the extent specified herein. Unless otherwise specified, the issues of these documents are those cited in the solicitation or contract (see 6.2). AEROSPACE INDUST
12、RIES ASSOCIATION OF AMERICA, INC. NASM25027 - Nut, Self-Locking, 250 Degrees F, 450 Degrees F, and 800 Degrees F FSC 5310. (A copy of this document is available from http:/www.aia-aerospace.org or from the Aerospace Industries Association of America, Inc., 1000 Wilson Boulevard, Suite 1700, Arlingto
13、n, VA 22209-3928, 703-358-1000). AMERICAN NATIONAL STANDARDS INSTITUTE (ANSI) NCSL-Z540.1 - Laboratories, Calibration, and Measuring and Test Equipment, General Requirements for (A Copy of this document is available from http:/www.ncsli.org/ or from the National Conference of Standards Laboratories
14、(NCSL), 2995 Wilderness Place Suite 107, Boulder, Colorado, 80301-5404, United States). AMERICAN SOCIETY FOR QUALITY ASQC Z1.4 - Sampling Procedures and Tables for Inspection by Attributes. (A copy of this document is available from http:/www.asq.org/ or from the American Society for Quality, 600 No
15、rth Plankinton Avenue, Milwaukee, WI 53203, USA). AMERICAN SOCIETY FOR TESTING AND MATERIALS (ASTM) ASTM D5948 - Standard Specification for Molding Compounds, Thermosetting. (Copies of this document are available online at http:/www.astm.org or from the American Society for Testing Materials, 100 Ba
16、rr Harbor Drive, West Conshohocken. PA 19428-2959). INTERNATIONAL ORGANIZATION FOR STANDARDS (ISO) ISO 10012-1 - Equipment, Quality Assurance Requirements for Measuring - Part 1: Metrological Confirmation System for Measuring Equipment. (A copy of this document is available from http:/ or the Intern
17、ational Organization for Standardization (ISO), 1, ch. de la Voie-Creuse, Case postale 56, CH-1211 Geneva 20, Switzerland, Tel.: +41 22 749 02 22, Fax: +41 22 749 01 55. Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-MIL-DTL-27715B 3 SOCIETY OF AUTO
18、MOTIVE ENGINEERS SAE-AS50861 - Wire, Electric, Polyvinyl Chloride Insulated, Copper or Copper Alloy. SAE-AS20659 - Terminal, Lug, Crimp Style, Copper, Uninsulated, Ring Tongue, Type I, Class 1 for 175C Total Conductor Temperature. SAE-AS25036 - Terminal, Lug, Crimp Style, Copper, Insulated, Ring-Ton
19、gue, Bell-Mouthed, Type II, Class 1 (for 105C Total Conductor Temperature). (Copies of these documents are available online at http:/www.sae.org/ or from the Society of Automotive Engineers, 400 Commonwealth Drive, Warrendale, PA 15096-0001.) 2.4 Order of precedence. Unless otherwise noted herein or
20、 in the contract, in the event of a conflict between the text of this document and the references cited herein (except for related specification sheets), the text of this document takes precedence. Nothing in this document, however, supersedes applicable laws and regulations unless a specific exempt
21、ion has been obtained. 3. REQUIREMENTS 3.1 Specification sheets. The individual item requirements shall be as specified herein and in accordance with the applicable specification sheet. In the event of any conflict between the requirements of this specification and the specification sheet, the latte
22、r shall govern. 3.2 Qualification. The circuit breakers furnished under this specification shall be products that are authorized by the qualifying activity for listing on the applicable QPL before contract award. 3.3 Selection of specifications and standards. Specifications and standards for necessa
23、ry commodities and services not specified herein shall be selected to meet the requirements of this specification, except as specified in 3.3.1 and 3.3.2. 3.3.1 Commercial parts. Commercial parts having suitable properties may be used where, on the date of invitation for bids, there are no suitable
24、standard parts. In any case, commercial utility parts such as screws, bolts, nuts, and cotter pins having suitable properties may be used provided: a. They can be replaced by the standard military parts without alteration. b. The corresponding standard part numbers are referenced in the parts list a
25、nd on the contractors drawings. 3.3.2 Standard parts. With the exception specified in 3.4.1, standard military parts shall be used where they suit the purpose. They shall be identified on the drawings by their part numbers. 3.4 Materials. Materials shall conform to applicable specifications and shal
26、l be as specified herein. Materials not covered by applicable specifications or not specifically described herein shall be of the best quality, of the lightest practicable weight, and suitable for the purpose intended. Materials shall be inherently fungus resistant. 3.4.1 Metals. Metals shall be cor
27、rosion-resistant or suitably treated to resist corrosion due to fuels, salt atmosphere, or atmospheric conditions that may be encountered in storage or normal service. 3.4.1.1 Dissimilar metals. Unless otherwise suitable protected, dissimilar metals, such as brass, copper, or steel, shall not be use
28、d in intimate contact with magnesium, aluminum, or their alloys. Where contact between dissimilar metals is unavoidable, the metals shall be protected against electrolytic corrosion. When thermostatic bimetals and trimetals are used, corrosion resulting from tests specified herein shall not adversel
29、y affect the performance of the breaker. Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-MIL-DTL-27715B 4 3.4.2 Plastics. Plastic materials used in the housing, insulator base, and any internal parts exposed to arcing or surface creepage shall confor
30、m to Specification MIL-I-24768/17, MIL-I-24768/1, or ASTM-D5948. Other types of plastic materials may be used provided the manufacturer submits satisfactory evidence to the activity responsible for qualification that the materials are suitable for the purpose intended. The plastic materials used sha
31、ll neither support combustion nor give off noxious gas when subjected to arcs, such as those caused by interrupting heavy short-circuit currents, or explosions of gaseous vapors to which the materials may be subjected in service. Plastic materials with cellulose fillers shall not be permitted in par
32、ts that may be subjected to arcing or surface creepage. 3.4.2.1 Color. The color of the plastic case for the circuit breaker shall be optional. 3.4.3 Protective treatment. When materials are used in the construction of the circuit breaker that are subject to corrosion in salt air or other atmospheri
33、c conditions likely to occur during service usage, they shall be protected against such corrosion in a manner that will in no way prevent compliance with the performance requirements of this specification. The use of any protective coating that will crack, chip or scale with age or extremes of atmos
34、pheric conditions shall be avoided. 3.5 Design and construction. The design and construction of the circuit breaker shall conform to the applicable specification sheet (see 3.1). If this specification and the specification sheet conflict, the specification sheet shall govern. 3.5.1 Mounting means. T
35、he circuit breaker shall be provided with a suitable mounting means as shown in the applicable specification sheet (see 3.1). Self-locking nuts shall meet the performance requirements of NASM25027. 3.5.1.1 Mounting screw clearance. The mounting screws shall be screwable into the circuit breaker to a
36、 minimum depth, as shown (see 3.1). 3.5.2 Actuator. The portion of the actuator visible when the circuit breaker is in the closed position shall be black and shall expose a white band when in the open or tripped position. The exterior portion of the actuator shall be insulated from all current carry
37、ing parts. The actuator shall not work out to an intermediate position, give a false trip indication, or be removable from the breaker. 3.5.2.1 Manual circuit opening. The circuit breakers defined herein shall be designed to permit manual opening of the circuit by pulling out the actuator. 3.5.2.2 T
38、rip indication and reset. The circuit breakers shall be so designed that when the breaker contacts open automatically on overload, the actuator shall indicate the operation by moving to the tripped position as shown (see 3.1). Resetting shall be accomplished in accordance with the applicable specifi
39、cation sheet. 3.5.3 Attitude. The circuit breaker performance shall be unaffected by mounting position. 3.5.4 Terminals. Terminal construction shall be as specified in the applicable specification sheet (see 3.1) and shall be designed for use with terminal lugs conforming to SAE-AS25036 or SAE-AS206
40、59. The use of pure tin as an underplate or final finish is prohibited. Tin content shall not exceed 97 percent, by mass. Tin shall be alloyed with a minimum of 3 percent lead, by mass (See 6.5). 3.5.5 Housing. The circuit breaker mechanism shall be enclosed in a housing securely attached to the ins
41、ulator base and to the mounting plate when one is used. The housing may be integral with the insulator base. 3.5.5.1 Strength of housing. The mounting nuts shall be backed or provided with other means to prevent mounting screws of excess length from interfering with the operation of the breaker. Scr
42、ews of excess length shall not fracture the housing or the explosion-proofing seal. 3.5.6 Screw threads. Screw threads on removable or replaceable threaded parts shall be as specified in Specification MIL-S-7742. Threading on non-metallic parts is not permitted. 3.5.7 Tamper-proof calibration. Circu
43、it breakers shall be so sealed that tampering with the calibration is not possible without dismantling the device or breaking the seal. Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-MIL-DTL-27715B 5 3.5.8 Environmental conditions. The unit shall pe
44、rform satisfactorily when subjected to any one or any combination of the following environmental conditions. There shall be no breakage, malfunction, or evidence of any damage that would impair the ability of the circuit breakers to meet the requirements of subsequent tests. a. Temperature. Temperat
45、ures from -53.9C (-65F) to 121C (250F). b. Altitude. Pressure altitude from sea level to 60,000 feet. c. Explosion-proof. Operation in an explosive atmosphere. d. Humidity. Relative humidity to 95 percent. e. Salt atmosphere. Exposure to salt laden atmosphere. f. Sand and dust. Exposure to sand and
46、dust. g. Vibration. Vibration incident to use in jet powered aircraft. h. Shock. Mechanical shock of 25g. i. Fungus. Moist fungi as encountered in tropical climates. j. Acceleration. Acceleration of 10g for one minute. 3.6 Performance. The circuit breakers shall be designed to perform satisfactorily
47、 in accordance with the following requirements. 3.6.1 Dielectric strength. Each circuit breaker shall withstand without damage, at sea level pressure, a potential of 1500 volts RMS alternating current at commercial frequency for 1 minute for each of the conditions as specified in section 4 herein. 3
48、.6.2 Insulation resistance. The insulation resistance between mutually insulated metal parts shall be 100 megohms or more. 3.6.3 Ultimate trip. At ambient temperatures from -53.9C (-65F) to 121.1C (250F), the circuit breaker shall trip in less than 60 minutes while carrying currents indicated by the
49、 trip curve, and shall not trip within 60 minutes while carrying currents indicated by the hold curve as shown in figure 1. When tripped in accordance with any condition shown by the trip curve, the breaker shall be resettable within 1 minute and with no load current. 3.6.4 Calibration. The circuit breaker shall trip within the limits defined on the applicable specification sheet (see 3.1). 3.6.5 Electrical losses. The voltage drop a
