1、MIL-G-3LLLC bL 999990b IlO4441 i4 - MIL-G-3 11 lC(SHIPs) 25 April 1961 SUPERSEDING 14 October 1955 MIL-G-SIllB(SHIPS) MILITARY SPECIFICATION GENERATORS, ELECTRIC, DIRECT-CURRENT (NAVAL SHIPBOARD USE) 1. SCOPE 1.1 Generators. - This specification covers direct-current (d. c.) generators up to 1,000 k
2、ilo- watt (kw.). 2. APPLICABLE DOCUMENTS 2.1 The following documents, of the issue in ef- fect on date of invitation for bids, form a part of this specification, to the extent specified herein: SPECIFICATIONS FEDERAL FF-B-171 - Bearing Ball, Annular, (General FF-B-185 - Bearings, Roller, Cylindrical
3、; Purpose). and Bearings, Roller, Self- Aligning MILITARY MIL-W-806 - Wire, Armature-Banding, Steel, Tinned. MIL-S-901 - Shockproof -Equipment, Class HI (High-Impact); Shipboard Application, Tests for. Power, Basic Require- ments for (Naval Ship- board Use). cedure For Procurement of. MIL-E-2036 - E
4、nclosures for Electric and Electronic Equipment (Naval Shipboard Use). Nonmagnetic, Iron- Chrome-Nickel-Alloy. tact; and Carbon Stock Electrical Contact, Brush. MIL -Q-9858 - Quaiity Control System Re- quirements. MIL-M-15071 - Manual, Technical, for Mechanical and Electrical Equipment (less Elec- t
5、ronics). MIL-T-15108 - Transformers, Power, Step- Down, Single Phase, 60 Cycle. 1-KVA Approximate MIL-E-917 - Equipment, Electric MIL-D-963 - Drawings, Production, Pro- MIL-W-3068 - Wire, Armature-Banding, MIL-B-3743 - Brushes, Electrical Con- - ._ .- Minimum Rating; And Re- actors (Balance coils)-
6、Dry, Naval Shipboard MIL-R-15109 - Resistors and Rheostats, Shockproof (Naval Ship- board Use). MIL-E-17555 - Electronic And Electrical Equipment And Associated Repair Parts, Preparation For Delivery Of. STANDARDS MILITARY MIL-STD-167 - Mechanical Vibrations of Shipboard Equipment. MIL-STD-740 - Noi
7、se Measurements of Shipboard Machinery and Equipment. (Copies of specifications, standards, drawings, and publications required by contractors in connection with specific procurement functions should be ob- tained from the procuring activity or as directed by the contracting officer. ) 2.2 Other pub
8、lications. - The following docu- ments form a part of this specification to the extent specified herein. Unless otherwise indicated, the issue in effect on date of invitation for bids shall apply. AMERICAN SOCIETY FOR TESTING MATERIALS ASTM A27-58 - Mild To Medium Strength Carbon Steel Castings For
9、General Application - Malleable Iron Castings - Carbon And Alloy Steel Ring And Disk Forgings - Nodular Iron Castings - White Metal Bearing Alloys - Aluminum Base Alloy Sand Castings - Aluminum Base Alloy Die Castings - Phosphor Bronze Rod, Bar, And Shapes - Leaded Yellow Brass Sand Castings For Gen
10、eral Purposes Plate ASTM A47-52 ASTM A243-55 ASTM A339-55 ASTM B23-49 ASTM B26-58T ASTM B85-58T ASTM B139-58 ASTM B146-52 ASTM B209-59T - Aluminum Alloy Sheet and /FSC 6115 I Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-MIL-G-JlllC(SHIPS) (Applica
11、tion for copies should be addressed to the American Society for Testing Materials, 1916 Race Street, Philadelphia 3, Pa. ). 3. REQUIREMENTS , 3.1 Definitions.- 3.1.1 Continuous duty. - Operation at a substan- tially constant load for an indefinite period of time. 3.1.2 Efficiency. - Ratio of the use
12、ful power out- put to the total power input. input where input is determined by addition of all component losses to the output. 3.1.3 Conventional efficiency. - Ratio of output to 3.1.4 Air-gap line. - Extended straight line part of the no-load saturation curve. 3.2 Performance requirements. - 3.2.1
13、 Rating. - The rating in kw, voltage and revolutions per minute (r. p. m. ) shall be as specified (see 6.1). 3.2.2 Efficiency. - The efficiency of the gener- ator shall be as specified (see 6.1). for the following voltages, as specified (see 6.1): 3.2.3 Voltage. - Generators shall be designed 120 Vo
14、lts 240 Volts 120/240 Volts 3.2.4 Dus. - Generators shall deliver rated cur- rent continuously at rated voltage and rated r. p. m 3.2.5 Overload. - When specified (see 6. i), each generator shaii also be capable of delivering at rated voltage and r.p. m., 125 percent rated kw load for 2 hours and 15
15、0 percent rated kw load for 5 minutes. 3.2.6 Unbalanced load rating (three wire gener- ators only). - The unbalanced load rating shall be 15 percent of the rated fui1 load current unless the gen- erator rating is 100 Kw or less, in which case it shall be 25 percent. 3.2.7 Overspeed. - Generators sha
16、ll be designed and constructed to withstand safely an overspeed of 25 percent (see 4.4.7). 3.2.8 Parallel operation. - When specified (see 6.1) generators shall be designed for parallel oper- ation. 3.2.9 Ambient temperatures. - Generators shall be designed for operation in an ambient temperature of
17、 50“ Centigrade (C). 2 3.2.10 Ripple voltage. - At any load from no load to full load and considering only peak-to-peak volt- age values, the commutator ripple at any frequency from zero to 16 kilocycles shall not exceed 2 percent of the rated output voltage. 3.2.11 Voltage regulation. - At rated r.
18、 p. m. the following requirements shall apply: (a) With the field rheostat so adjusted that the generator is operating at rated voltage at no load, the drop in voltage shall be not more than 10 percent when rated load is applied to the generator (see 4.4.11). (b) With the field rheostat so adjusted
19、that the generator is operating at rated voltage at rated load, the rise in voltage shall not be more than 6 percent when the load is reduced to zero (see 4.4.11). (c) At any point on the voltage-load curve with the generator field rheostat adjusted as specified in (a) and (b) above, there shall be
20、no rise in voltage with increase in load, or any drop in voltage with a drop in load. 3.2.12 Prime movers. - Generators shall operate satisfactorily with the following types of prime movers as specified (see 6.1): Steam turbine Gas turbine Diesel engine Gasoline engine. 3.2.13 Responsibility of prim
21、e mover manufac- turer. - It shall be the responsibiiity of the prime mover manufacturer to provide a prime mover of sufficient capacity to drive the generator under ail conditions of load and overload specified herein (see 6.3). 3.3 Design and construction. - 3.3.1 Basic requirements. - Generators
22、shall conform to Specification MIL-E-917 and the require- ments specified herein. tures which will result in reliable and stable opera- tion with minimum need for adjustment and aign- ment, minimum frequency of failure and minimum requirements for maintenance. 3.3.3 Distribution system. - The distri
23、bution system shall be two-wire unless three-wire is speci- fied (see 6.1). 3.3.2 Reliability. - The design shaU include fea- 3.3.4 Winding. - Generators shall be either shunt- wound where no series field is provided or stabiiized shunt wound where a light series field winding is pro- vided to maint
24、ain the required voltage regulation. For stabilized shunt wound generators, at rated full Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-MIL-G-31 1 lC(SHIPS) load voltage and current, the ratio of series field ampere-turns to shunt field ampere-turn
25、s shall not exceed 15 percent. 3.3.5 Dielectric strength. - Generators shall withstand a dielectric strength test voltage of twice normal voltage of the circuit concerned plus 1,000 volts, when tested in accordance with 4.4.9. 3.3.6 Insulation resistance. - The insulation resistance, when corrected
26、to 25C. , shall not be less than the following (see 4.4.8): Megohms 12 Armature circuit (class A insulated) Armature circuit (class B, F or H Field circuit (class A insulated) Field circuit (class B, F, or H 50 25 50 insulated) insulated) 3.3.7 Temperature limits. - At rated r. p. m., voltage and kw
27、. load (see 4.4.12), the temperature rise of the various parts of the generator, shall not exceed the maximum permissible temperature rises specified in table I. Table I - Maximum permissible temperature rises (based on 50C ambient continuous rated load). Part Coils and connections; (Method 1, measu
28、red by the thermometer, as specified in MIL-E-917). ia) Open (b) Protected, dripproof protected (c) Others Windings - method 2 (resistance as specified in Specification MIL-E-917) (a) Open (b) Protected, dripproof protected (c) Others Commutators (a) Open (b) Others Bearings Miscellaneous parts as b
29、rush holders, brushes, pole tips, and similar parts may attain such temperatures as will not injure the generators in any respect. Cores, poles, and other mechanical parts in contact with insulation . Mechanical parts: 3.3.8 Radio interference. - Generators shall be designed to cause a minimum of ra
30、dio interference at all loads and speeds within the operating range. Radio interference suppression equipment shall not be used unless permitted by the contract or order to meet specific radio interference limits (see 6.1). Aa a means of reducing radio interference, con- sideration shall be given th
31、e following: (a) Commutating poles. (b) Compensating windings. A 30 40 45 40 50 55 45 55 60 Insulation cl ass B 50 60 65 65 70 75 75 75 60 Same as for I F 75 85 90 90 95 100 100 100 60 H 110 120 125 130 135 140 135 135 110 e insulation with which the parts are in contact (c) Split series, commutatin
32、g pole and com- pensating windings with half of the wind- ings on each side of the armature. (d) increased number of armature coils and commutator bars. (e) Shallow armature slots. (f) Short-pitch armature windings. (g) Reduced eccentricity between commutator and bearing. (h) Balanced design to elim
33、inate shaft and bearing currents without the use of auxiliary brushes. I 3 Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-MIL-G- 3111C(SHIPS) * 3.3.9 Airborne noise. - Generators shall be de- signed to produce minimum airborne noise at ail loads and
34、 speeds within the operating range. In addition, when specified (see 6. i), these generators shall meet specified airborne noise limits. As a means of reducing airborne noise, consideration shall be given the following: Number of slots per pole pitch. Number of slots magnetically under one pole. Slo
35、t frequency as a function of natural frequency of the frame. Skewing of slots or pole tips. Eliminating brush chatter. Stiffening of brush rigging. Aerodynamic design of the ventilating or cooling system. Mechanical balance. 3.3.10 Stray magnetic fields. - When specified (see 6. i), generators shall
36、 incorporate the follow- ing design features in order to reduce stray mag- netic fields. In addition, when specified (see 6. i), these generators shall meet specified stray mag- netic field limits: The area of electrical current loops shall be made as small as possible and adjacent loops shall be ar
37、ranged so that their fields will be in opposition. Current loops shall enclose no magnetic material unIess essential for proper performance of equipment. All generator windings and connections shall be balanced for ampere turns around the shaft. Each circuit which makes even part of a turn around th
38、e machine shall return on itself back to the starting point, with conductors for the forward and reverse currents arranged at the same end of the machine and as close as adequate insulation permits. All connections shall be as short as possible. Brush rings shall be complete rings of uniform resista
39、nce throughout. Leads to the positive and negative brush rings shall be located as close together as possible. Individual main pole gaps shall be within plus or minus 10.0 percent of the average main pole gap. The sum of the north pole main gaps shall be within 5 percent of the sum of the south pole
40、 gaps. The same requirements shall apply to com- mutating pole gaps. Generators rated 100 watts and larger shall have four or more main field (j) The number of commutating poles shall be the same as the numkr of main field poles. (k) The number of turns in any field pole winding (shunt, series, comm
41、utating) shall be the same on each pole. (1) Magnetic frames shall be solid. (m) Yoke welds shall be at main poles. (n). The outside of the magnetic frame shall be a smooth figure of revolution. Protuber- ances of magnetic material, such a feet or supports shall not be used. Field pole bolts shall b
42、e recessed, and, in general, every effort shall be made to ensure that the outside of the magnetic frame is a smooth surface generated by revolving the arc of a curve about the axis of the machine. 3.3.11 Shock. - Generators shall be capable of withstanding high impact shock in accordance with Grade
43、 I of Specification MIL-S-901. 3.3.12 Vibration and balance. - Generators shall meet the vibration and balance requirements of Type II of Standard MIL-STD-167. Balancing shall be ef- fected by the use of steel balance weights attached by noncorrodible bolts securely locked by steel weights dovetaile
44、d and suitably anchored in balance grooves, by drilling out material, or by securely welded steel weights. The use of babbitt or lead as a balancing medium is not permitted. When metal strips or wedges are used in armature slots for final balancing of wound armatures, they shall be well insulated fr
45、om the armature core. Final dynamic balancing of com- pletely wound armatures by the use of solder on the banding wire is permissible subject to the following limitat ions : (a) Diameter of the armature shall not exceed 16 inches. (b) Peripheral speed shall not exceed 6,500 feet per minute at rated
46、speed. (c) All armature cores shall be balanced be- fore the windings are inserted. (d) The solder shall not cover an arc more than 25 percent of the armature meas- ured on the banding wire. Where the manufacturer takes care in placing the windings in the slots to reduce unbalance due to axial misal
47、ignment of the coils this value may be increased to 33 percent. (e) Thickness of solder over banding wire shall not exceed 3/32 inch, and in no case extend past the center of the air gap. 3.3.13 Material. - The minimum requirements for materials to be used in generators shall conform to the requirem
48、ents of Specification MIL-E-917 and table II. For those materials where no sDecifications poles. are listed the material sul be of a grad suitable 4 Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-MIL-C-3LLLC bL 9999406 OOBYYLIS L = for the performan
49、ce and shockproofness intended. Drawings shall indicate the specific commercial identification of commercial materials used. 3. 3.13. 1 Non-magnetic generators. - When non-magnetic generators are specified (see 6.1) generators shall conform to the following material requirements: (a) Except as specified in 3. 3.13.1(c), all parts including nuts, bolts, screws, lifting eyes and miscellaneous hardware shall be of non-magnetic material. (b) Non-magnetic material is defined as ma- terial having a maximum rel
