1、A-A-50631 m 9999974 0366552 722 pmq A-A-50631 9 February 1995 COMMERCIAL ITEM DESCRIPTION BUS FAILURE ALARM, ELECTRICAL, SHIPBOARD The General Services Administration has authorized the use of this commercial item description for all Federal Agencies. 1. Abstract. This commercial item description co
2、vers various types of bus failure alarms for naval ships. 2. Salient characteristics. 2.1 Mountinp;. Bus failure alarms shall be capable of bulkhead, panel, console, or internal mounting as specified (see 6.1). 2.2 Enclosure. Bus failure alarms shall be dripproof or explosionproof as specified (see
3、6.1). 2.2.1 Drimroof enclosure. An enclosure in which the openings are so constructed that drops of liquid or solid particles falling on the enclosure at any angle not greater than 15 degrees from the vertical either cannot enter the enclosure, or if they do enter the enclosure, they will not preven
4、t the successful operation of, or cause damage to, the enclosed equipment (see IEEE 45). 2.2.2 Explosionproof enclosure. Explosionproof enclosures shall be approved for operation in accordance with NFPA 70, class 1, group D, division 2, hazardous areas. Beneficial comments (recommendations, addition
5、s, deletions) and any pertinent data which may be of use in improving this document should be addressed to: Commander, SEA 03R42, Naval Sea Systems Command, 2531 Jefferson Davis Hwy, Arlington, VA 22242-5160 by using the self-addressed Standardization Document Improvement Proposal (DD Form 1426) app
6、earing at the end of this document or by letter. AMSC N/A FSC 6350 DISTRIBUTION STATEMENT A. Approved for public release; distribution is unlimited. Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-A-A-50631 m 9999974 0166553 bb9 m A-A- 50631 2.2.3 Gr
7、oundinp and bondin%. Metallic enclosures shall be provided with a stud for grounding and bonding. of the enclosure or any exposed metallic components shall be zero ohms when measured with a high quality ohmmeter. of the enclosure when viewed from the front of the bus failure alarm. Bus failure alarm
8、s designed for panel, console, or internal mounting do not require a stud for grounding and bonding, but must ensure that all metallic components will not create a shock hazard to personnel after installation. Resistance between tip of the stud and any point The stud shall be placed on the left side
9、 2.3 Electrical isolation. Electrical components shall be electrically isolated from the enclosure or any exposed metallic components. Electrical isolation shall be 100 megohm or greater when measured with a high quality, 500-volt megger. 2.4 TvDes. Bus failure alarms shall be capable of single-phas
10、e or direct current, or three-phase voltage detection as specified (see 6.1). 2.4.1 Sinee-phase or direct current. The single-phase root mean square (rms) or direct current (dc) bus failure alarm shall be a self contained unit providing an audible and visual indication when the monitored voltage fal
11、ls below 50 to 70 volts DC or rms. The bus failure alarm shall also provide an indication of normal voltage available. The bus failure alarm shall monitor dc or rms without modification and without observing polarity of the dc voltage. The audio shall provide an output of 88 decibel (dB) for 15 minu
12、tes without external power, be capable of being silenced, and auto reset to normal when the monitored voltage exceeds 75 to 90 volts. The visual indicator shall remain alarmed until manually reset. Sound pressure output shall be based on a reference of 20 micropascal (pPa), and shall be measured at
13、a distance of 3 meters (m) from the bus failure alarm in accordance with ANSI S1.13. 2.4.2 Three-phase. The three-phase bus failure alarm shall be capable of monitoring 115 or 440 volts rms with an operating frequency of 60 or 400 hertz (Hz). The bus failure alarm shall have an adjustable time delay
14、 for dropout or recovery from O to 10 seconds, and provide a solid state or relay output for an extension alarm capable of at least 5 amperes when the monitored voltage falls at least 15 percent. The accuracy of the bus failure alarm shall be at least 1 percent. 2.5 Construction. Construction shall
15、be such that no special tools are required for disassembly or reassembly. 2.6 Preservation. Parts shall be of suitable corrosion resistant material or materials treated in a satisfactory manner to render them adequately resistant to corrosion. 2 Provided by IHSNot for ResaleNo reproduction or networ
16、king permitted without license from IHS-,-,-A-A-50631 3. Ouality assurance Drovisions. 3.1 Contractor certification. The contractor shall certify and maintain substantiating evidence that the product offered meets the salient characteristics of this commercial item description and that the product c
17、onforms to the pro- ducers own drawings, specifications, standards, and quality assurance practices. The Government reserves the right to require proof of such conformance prior to the first delivery and thereafter as may be otherwise provided for under the provisions of the contract. 3.2 ReFulatorv
18、 rewirements. The offerer/contractor is encouraged to use recovered materials in accordance with Public Law 94-580 to the maximum extent practical. 4. Preservation. packaping. - packing. labelinn. and marking. The preserva- tion, packaging, packing, labeling, and marking shall be as specified in the
19、 contract or order. 5. CID based part identification number. The following part identification numbering procedure is for Government purposes and does not constitute a require- ment for the contractor. ,-A-50631 - PES46 Example of part identification. Variable characteristics P = mounting type E = e
20、nclosure type S = type of alarm 4 = operating voltage 6 = operating frequency CID number Designated commercial item description (CID) 6. Notes. 6.1 Acquisition reauirements. Acquisition documents must specify the following: (a) Mounting. B = Bulkhead P - Panel C = Console I = Internal D = Dripproof
21、E = Explosionproof (b) Enclosure. 3 Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-A-A-50b3L 9 9999974 OLbb555 431 = A-A-50631 (cl Type. S = Single-phase or Direct current T = Three-phase 1 = 115 volts 4 - 440 volts 6 = 60 HZ 4 = 400 HZ 6.2 Document
22、s. (a) NFPA-70, National Electrical Code, is available from National Fire Protection Association, One Batterymarch Park, P.O. Box 9101, Quincy, MA 02269-9101. available from American National Standards Institute, 11 West 42nd Street, 13th Floor, New York, NY 10036. board, is available from Institute
23、 of Electrical and Electronic Engineers, Inc., 445 Hoes Lane, P.O. Box 1331, Piscataway, NJ (b) ANSI S1.13, Methods for Measurement of Sound Pressure Levels, is (c) IEEE 45, Recommended Practice for Electric Installations on Ship- 08855-1331. CIVIL AGENCY COORDINATION ACTIVITY: GSA - FSS Preparing activity: Navy - SH (Project 6350-0141) 4 Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-
