1、 A-A-59003 = 9999974 OLb79L7 L47 METRIC 1 A- A- 59 O 03 MIL-A- 2 1577A 27 February 1967 COMMERCIAL ITEM DESCRIPTION AMPLIFIERS, AUDIO FREQUENCY; AND AMPLIFIER-CONTROL GROUPS-SHIPBOARD ANNOUNCING The General Services Administration has authorized the use of this commercial item description as a repla
2、cement for MIL-A-21577A which is canceled. 1. Scope. This Commercial Item Description covers audio frequency amplifiers and controls, shipboard announcing type, for use aboard Naval ships. The above amplifiers are to be employed as units in shipboard announcing systems which disseminate alarm signal
3、s, commands, and information as required in the tactical operation of Naval surface ships and submarines. 2. Salient characteristics. 2.1 Specification sheets. The individual item requirements shall be as specified herein and in accordance with the applicable specification sheet. In the event of any
4、 conflict between the requirements of this Commercial Item Description and the specification sheet, the latter shall govern. 2.2 Description. The equipment shall consist of amplifier assemblies, or amplifier-oscillator assemblies including control facilities, such as switches and relays, mounted in
5、racks or enclosures. 2.3 General characteristics. 2.3.1 Prohibited materials. The materials listed below shall not be used in the construction of Audio Frequency Amplifiers. (1 Flammable materials ( 2 ) Wood (3) Asbestos; asbestos compounds; and asbestos-filled molding (4) Lithium and lithium compou
6、nds (5) Magnesium or magnesium alloy compounds Beneficial comments, recommendations, additions, deletions, clarifications, etc. and any other data which may improve this document should be sent by letter to: Commander, Naval Sea System Command, Attn: 03R42, 2531 Jefferson Davis Highway, Arlington, V
7、A 22242-5160. msc N/A FSC 6320 DISTRIBUTION STATEMENT A. Approved for public release; distribution is un1 imi ted. Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-A-A-59003 9999774 OLb7l18 085 = D 21 A-A- 5 9003 Zinc or zinc alloy Carcinogens Radioac
8、tive material Polychlorinated Biphenyl (PCB) Polyvinyl Chloride (PVC), except where used for component leads Mercury or its compounds and amalgams Cadmium Chloroflourocarbons 2.3.2 Inert materials. All materials shall be fungus inert or shall be suitably treated to retard fungus growth. The manufact
9、urer shall certify that all external materials are fungus resistant or shall test the material in accordance with ASTM G21. There shall be no evidence of fungus growth on the surfaces of amplifier components. 2.3.3 Metal parts. Metal parts shall be of a corrosion-resistingmaterial or of a material g
10、iven a corrosion-resistant coating or treatment. Material selection shall consider the minimization of bimetallic corrosion. 2.3.4 Aluminum alloys. Aluminum alloys shall conform to applicable NSTM standards. 2.3.5 Non-ferrous metals. Non-ferrous metals shall conform to commercial standards. 2.3.6 Th
11、ermoplastic materials. Plastics which melt or soften under test conditions imposed by this product description shall not be used. approval. 2.3.7 Ceramics. Use of ceramics requires the procuring activitiys 2.3.8 Glass. All glass for use in units or protection of meters and for viewing dials and indi
12、cators shall be clear, presenting no evidence of distortion when viewed from any angle. 2.3.9 Painting. Enclosures shall be completely painted in accordance with Plastic and composite materials normally will not be best commercial practices. painted. Exterior enclosure color shall be gray. 2.3.10 Fa
13、steners. Fasteners shall conform to FED-STD-H28. 2.3.11 Input power. This equipment shall operate from nominal 115 volt AC, 60 hertz. Voltage tolerance shall be 26 volts (VI. Frequency tolerance shall be 2 3 cycles per second (Hz). 2.3.12 Power transients. Equipment design shall be such that under a
14、ny mode of operational switching of the equipment, including on or off, or with an input supply over voltage of 300 percent for a period of 1 millisecond, the output voltage of the equipment power supply (or supplies) shall not vary by more than 20 percent. This capability shall be verifiable by sup
15、erimposing a one millisecond pulse of 300 percent overvoltage onto the supply voltage. The output of the equipments power supplies shall be observed on a calibrated oscilloscope, while the equipment is switched through all operational modes to determine conformance. 2.3.12.1 Power transient regulati
16、on in percent of nominal. (a) Voltage. Plus or minus 18 percent outside of steady state band. Recovery within 3 percent of steady state band in 2 seconds. 2 Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-A-A-59003 W 9999974 0167919 TL1 A-A- 59003 (b
17、) Frequency. 3 percent dip of which no more than 1 percent is outsidesteady state band. Recovery within statdy state band in 2 seconds. Approximately one-half of the voltage dip shall occur within the first one-half cycle after initiation of the disturbance. Minimum voltage shall occur in O. 1 to 0.
18、3 second. After the maximum negative voltage excursion, the voltage shall overshoot to a maximum value which can be as great as the negative excursion. The total period of this transient shall not exceed a total time period greater than 2 seconds. 2.3.12.2 Power supply harmonic content. The equipmen
19、t shall perform satisfactorily when the power supply contains harmonics of the following values: total harmonic content of not more than 5 percent and maximum of any one harmonic of 2 percent. 2.3.13 Indicator lights. Indicator light globes or lenses shall conform to the following color scheme: Yell
20、ow Open. Amber Abnormal but not immediately dangerous condition. Blue . Closed (shut). Green Normal Red . Dangerous or emergency condition. White Power on or power available. For equipment in spaces where dark adaptation of personnel is required, indicators with red lenses and stencil-type markers d
21、iscs shall be used. 2.3.14 Fuses. Glass type fuses shall not be used. 2.3.15 Fuseholders. Fuzeholders shall be of the indicating type, with indicator illumination ceasing when the fuze opens. 2.3.16 Enclosure mounting. The design shall provide for three point suspension for bulkhead mounting, and th
22、ree or four point suspension for panel mounting. The three mounting feet for bulkhead designs shall provide two feet at the top and one foot at the bottom. The method of mounting on panels shall incorporate design features whereby the flange of the case and shall be so arranged that the entire inter
23、ior subassembly can be withdrawn from its case without disturbing the panel mounting bolts. 2.3.17 Size. No unit may be over 183 centimeters (cm) overall height as installed. Any unit, when uncrated for installation and without further disassembly, shall be capable of passage through doors and hatch
24、es. For equipment destined for surface ships, this requires passage through a door 66 cm wide by 114 cm high (reduced by round corners on a 20.3 cm radius), and through a hatch 76 cm long by 76 cm wide (reduced by round corners on an 11.4 cm radius). For equipment destined for submarines, this requi
25、res passage through a door 50.8 cm wide by 96.5 cm high (reduced by round corners on a 25.4 cm radius) and through a circular hatch 63.5 cm in diameter. 2.3.18 Rounded corners and edges. All edges and corners of external surfaces, normally exposed or to be painted, shall be rounded. Sharp edges and
26、points of any kind shall be avoided. 2.3.19 internal subassembly protection. Complete unit internal subassemblies shall be provided withmeans to prevent injury to pointers, dials, and other parts when the subassembly is removed from its enclosure and rested on a work bench on either its top or botto
27、m. 2.3.20 Temperature. The operating temperature limits shall be -20 degrees Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-A-A-59003 W 9999974 0167920 733 t A-A- 5 9 O O 3 centigrade (OC) to +5OoC. The non-operating temperature limits shall be -40C
28、 to +7OoC, for unsheltered shipboard use. 2.3.20.1 Non-operating temperature. The units shall meet the performance requirements of this commercial item description after exposure to low temperature for 1 hour and high temperature for 2 hours, with the non-operating temperature values specified above
29、. 2.3.20.2 Operating temperature. The units shall satisfy the following high and low operating temperature tests: 2.3.20.2.1 Operating high temperature. The units shall meet the performance requirements of this commercial item description while at the high operating temperature (+ 1OC) specified abo
30、ve for 1 hour. The relative humidity shall be maintained at less than 20 percent. After exposure to high operating temperature, the units shall satisfy the requirements of this commercial item description after 1 hour or more at room temperature. 2.3.20.2.2 Operating low temperature. The units shall
31、 meet the performance requirements of this commercial item description while at the low operating temperature (2 1C) specified above for 1 hour. The relative humidity shall be maintained at greater than 85 percent. After exposure to low operating temperature, the units shall satisfy the requirements
32、 of this commercial item description after 1 hour or more at room temperature. 2.3.21 Humidity. The units shall meet the performance requirements of this commercial item description when subjected to a relative humidity of 100% at 24O to 27OC for three hours. 2.3.22 Degree of enclosure. Racks or enc
33、losures shall be dripproof on top. Other surfaces may be open as necessary to promote maximum air circulation for cooling. The top shall be so constructed that water falling from directly overhead cannot enter the enclosure, whentestedin accordance with the following procedure: Drips or sprinkles of
34、 water shall be allowed to fall over the entire top surface of the enclosure, with the minimum amount of water being 176 liters per square meter of enclosure top surface, in a period of 60 minutes. The dripping or sprinkle rate and distribution shall be approximately uniform. The equipment shall be
35、operating for two thirds of the test period and off for the remainder. Failure of the equipment to operate satisfactorily or accumulation of water within the enclosure shall be cause for rejection. 2.3.23 Inclination. Units shall operate satisfactorily when inclined up to 45 degrees from the vertica
36、l in any direction for surface ships equipment and up to 60 degrees from the vertical in any direction for submarine equipment. 2.3.24 Vibration. The units shall meet the requirements of this commercial item description during and after the Type III vibration test of EIA RS-186-7, modified to includ
37、e the frequency range of 1 to 55 Hz vice 10 to 55 Hz. Mounting shall be identical to that intended for service. Test shall be conducted under full electrical load, with all circuits energized. No movement or resetting of switches, relays, or controls shall be evident during or after the course of sh
38、ock testing. 2.3.25 Shock. The units shall meet the requirements of this commercial item description when tested for durability in a shock environment. The shock test procedure shall be agreed upon by the contractor and the government, and may include the following test method. The loudspeaker shall
39、 be mounted to a support fixture. The support fixture shall be similar in size, shape, and attachment methods so as to simulate the unit mounting area. Tested items shall be attached to their shock test fixtures in accordance with the manufacturers installation 4 Provided by IHSNot for ResaleNo repr
40、oduction or networking permitted without license from IHS-,-,-A-A-59003 W 9999974 OLb92L b7T W . A-A- 590 03 drawings. This method of mounting shall reflect the intended shipboard installation. The support fixture, with test sample attached, shall be mounted to an anvil plate which will receive the
41、shock impact. The total weight supported by the shock machine anvil plate (excluding weight of anvil plate itself but including all structure and equipment added to the anvil plate) shall not exceed 250 kg. Practical size limitations shall not be exceeded. The contractor may recommend the use of a n
42、onstandard fixture for approval by the acceptance authority. When the equipment has been mounted for test upon the fixture, its position upon the fixture shall not be changed during the course of the test. 2.3.25.1 Shock test sequence. For all items subject to lightweight shock testing, three blows
43、at hammer heights of 30.5 cm, 91.4 cm, and 152.4 cm shall be applied to each of three mutually perpendicular axes of the item being tested. Hammer weight shall be 181.4 kg. This is accomplished by attaching the test item by fixture to an anvil plate and striking the anvil plate by top, back, and sid
44、e blows. The sequence of the testing may be varied at the discretion of the contracting activity and the contractor. In some cases, it may be more beneficial to conduct a 30.5 cm test in each of the three mutually perpendicular axes, followed by the 91.4 cm tests and then the 152.4 cm tests. The abo
45、ve series of nine blows shall be conducted with the units in operation. Separate items may be substituted for each additional set of nine blows, if desired by the contractor. 2.3.25.2 Shock fastener inspection. Exposed bolting, screws, and similar exposed fasteners associated with the tested item ma
46、y be tightened before each test blow or shot only as necessary to compensate for loosening due to seating-in of mating surfaces, as demonstrated by suitable pre- and post- shock measurements. If it cannot be demonstrated (e.g. by bolt length measurements) that fasteners have not yielded, the fastene
47、rs shall not be retightened and subsequent shock blows and performance tests shall be conducted with the fasteners in the as-found condition. Torques for applicable bolting shall be measured and recorded following each shock test blow or shot. Excessive yielding or loosening of fasteners shall be co
48、nsidered as a violation for shock test acceptance criteria. Yielding or loosening of fasteners and yielding or cracking of structural members or component parts shall be reported in shock test reports when such reports are required by the contract or order. 2.3.25.3 Shock test evaluation. All shock
49、tested units shall be disassembled and inspected for breakage, deformation, and misalignment. No movement or resetting of switches, relays, or controls shall be evident during or after the course of shock testing. 2.3.25.4 Shock test administration. See “Quality assurance provisions“ for administrative information on shock testing. 2.3.26 Safety. applicable safety features. Units shall comply with NFPA 70 and ASTM F-1166 regarding 2.3.27 Shielding and radio frequency noise reduction. The equipment
