1、 AMSC N/A FSC 6620 MIL-PRF-26611F 14 August 2013 SUPERSEDING MIL-PRF-26611E 15 May 1996 PERFORMANCE SPECIFICATION GENERATOR, TACHOMETER GEU-7/A, MINIATURE This specification is approved for use by the Department of the Air Force and is available for use by all Departments and Agencies of the Departm
2、ent of Defense. 1. SCOPE 1.1 Scope. This specification defines a miniature, electric, two-pole, ac tachometer generator for use in generating electrical signals for transmission to aircraft indicating instruments. 2. APPLICABLE DOCUMENTS 2.1 General. The documents listed in this section are specifie
3、d in sections 3, 4, or 5 of this specification. This section does not include documents cited 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
4、they must meet all specified requirements of the documents cited in sections 3, 4, or 5 of this specification, whether or not they are listed. 2.2 Government documents. 2.2.1 Specifications. The following specifications form a part of this document to the extent specified herein. Unless otherwise sp
5、ecified, the issues of these documents are those cited in the solicitation or contract. DEPARTMENT OF DEFENSE SPECIFICATIONS MIL-PRF-7808 - Lubricating Oil, Aircraft Turbine Engine, Synthetic Base MIL-PRF-23699 - Lubricating Oil, Aircraft Turbine Engine, Synthetic Base, NATO Code Number 0-156 INCH-P
6、OUND Comments, suggestions, or questions on this document should be addressed to Oklahoma City Air Logistics Center/ENSDAA, 3001 Staff Drive, Tinker AFB, OK 73145 or emailed to tinker.dsptinker.af.mil. Since contact information can change, you may want to verify the currency of this address informat
7、ion using the ASSIST Online database at https:/assist.dla.mil. Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-MIL-PRF-26611F 2 (Copies of these documents are available online at http:/assist.dla.mil/quicksearch/ or from the Standardization Document
8、Order Desk, 700 Robbins Avenue, Building 4D, Philadelphia, PA 19111-5094.) 2.3 Order of precedence. Unless otherwise noted herein or 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 th
9、is document takes precedence. Nothing in this document, however, supersedes applicable laws and regulations unless a specific exemption has been obtained. 3. REQUIREMENTS 3.1 Qualification. Generators furnished under this specification shall be products that are authorized by the qualifying activity
10、 for listing on the applicable qualified products list before contract award (see 4.2 and 6.3). 3.2 Recycled, recovered, or environmentally preferable materials. Recycled, recovered, or environmentally preferable materials should be used to the maximum extent possible, provided that the material mee
11、ts or exceeds the operational and maintenance requirements, and promotes economically advantageous life cycle cost. 3.3 Materials. Unless otherwise specified, materials shall be non-magnetic and nonferrous. Materials shall not produce deleterious fumes and shall be treated to resist corrosion due to
12、 electrolytic decomposition, fungus, fuels, salt spray, or any other conditions that may be encountered during operation, use, or storage. 3.4 Interface. 3.4.1 Dimensions. The generator shall conform to the dimensions in Figures 1 and 2. 3.4.2 Electrical connector and mounting. The 2-pin connector f
13、or the generator shall conform to MS33678-12S-3P. The threaded portion of the connector shall be located within 0.375 inch from the rear of the generator. The mounting shall withstand a force of 17 foot-pounds bending movement applied in any direction perpendicular to the longitudinal axis of the co
14、nnector without damage. 3.4.2.1 Connections. The generator winding leads shall be designated B, A, and C (conforming to phases 1, 2, and 3). The B and A leads shall be connected to the B and A pins of the connector and the C lead shall be grounded to the generator frame. Voltage phase rotation is B,
15、 A, and C when rotating the generator drive shaft counterclockwise. 3.4.2.2 Connector shell. The shell shall be electrically grounded to the generator case. In addition, the shell shall be permanently marked FOR USE WITH PERCENT RPM INDICATORS ONLY. The letters shall be at least 0.093 inch high and
16、clearly visible and easily readable on opposite sides of the shell. Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-MIL-PRF-26611F 3 3.4.3 Lubrication resistance. The generator shall be resistant to oil conforming to MIL-PRF-7808 or MIL-PRF-23699. 3.
17、5 Environmental conditions. The generator shall be capable of operation under the following conditions: a. Temperatures ranging from -85 to 450F. b. Vibration up to 20g at frequencies from 5 to 2,000 Hz. c. Relative humidity up to 100 percent. d. Oil temperatures from -50 to 350F. e. Altitude to 80,
18、000 feet. f. An explosive atmosphere without igniting a fuel vapor-laden environment. 3.6 Performance. 3.6.1 Overspeed and reverse operation. The generator shall operate at any speed up to 5,500 rpm in either direction of rotation and in any mounting position. The generator output voltage shall be t
19、hree phase and have a frequency of one cycle per revolution of the generator drive shaft. 3.6.2 Dielectric strength. There shall be no insulation breakdown when a potential of 500 V root mean square (rms) is applied between any electrical pin contact and any metal part of the generator case without
20、the C lead grounded. 3.6.3 Voltage output. The output voltages shall be 21 0.5 when operated at a drive shaft speed of 4,200 rpm and connected to a load consisting of three 40-ohm, Y-connected resistances. None of the output voltages shall be less than 3.5 when operated at a drive shaft speed of 1,0
21、00 rpm and connected to a load consisting of three 20-ohm, Y-connected resistances. 3.6.4 Case. 3.6.4.1 Leakage. The generator case shall withstand oil leakage from the engine into the generator mounting flange at maximum rate of 0.3 inch per hour. 3.6.4.2 Drainage. Oil and combustible fumes shall n
22、ot accumulate in the case. 3.6.5 Shaft. 3.6.5.1 Hardness. Hardness of the drive end of the shaft shall be Rockwell C-30 to C-40. 3.6.5.2 Strength. The shear section of the drive shaft shall withstand 40 5 inch-pounds of torque, and twist through a minimum of 270 degrees before yielding. Provided by
23、IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-MIL-PRF-26611F 4 3.6.5.3 Flexibility. The shaft face shall be capable of moving 0.016 inch in any direction about the generator centerline without rotating or bending the shaft. The shaft rotational backlash about
24、its longitudinal axis shall not exceed 6 angular degrees. Free axial play shall not exceed 0.021 inch. Shaft deflection from the generator centerline shall not exceed 10 degrees. 3.6.6 Weight. The generator shall not exceed 1.2 pounds. 3.6.7 Interchangeability. All parts having the same manufacturer
25、s part number shall be functionally and dimensionally interchangeable. 3.6.8 Reliability. The generator shall have a minimum mean time between failures (MTBF) of 3,000 hours. 3.6.9 Maintainability. No special tools shall be required for the installation, removal, adjustment, or repair of the generat
26、or. 4. VERIFICATION 4.1 Classification of inspections. The inspection requirements specified herein are classified as follows: a. Qualification inspection (see 4.2). b. Conformance inspection (see 4.3). 4.2 Qualification inspection. Qualification shall be performed on eight generators. Four generato
27、rs shall be subjected to all tests in 4.6, one shall be used for the fungus test (see 4.6.15), and three shall receive the shaft failure test (4.6.20). 4.3 Conformance inspection. Conformance inspection shall consist of tests indicated in 4.3.1 and 4.3.2. 4.3.1 Individual tests. Each generator shall
28、 be subjected to tests indicated in 4.6.1 through 4.6.5. 4.3.2 Sampling tests. For the first 100 generators, 10 shall be selected randomly, and for each additional 100 units, 5 generators shall be selected randomly and subjected to the tests in 4.6.1 through 4.6.7 and 4.6.10 4.4 Inspection condition
29、s. 4.4.1 Atmospheric conditions. Unless otherwise specified, all tests shall be performed at room temperature and atmospheric pressure. 4.4.2 Voltages. All voltages are rms values. The voltmeter shall have an accuracy of 1% or better, and meter errors shall not be included in errors attributable to
30、the generator. 4.4.3 Test indicator. Unless otherwise specified, a percent rpm indicator shall be used. Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-MIL-PRF-26611F 5 4.4.4 Standard load. The standard load shall consist of three 40-ohm, Y-connected
31、 resistances. 4.5 Requirements cross-reference matrix. Table I provides a cross-reference matrix of the section 3 requirements tested or verified in the paragraphs below. Table I. Requirements cross-reference matrix. Requirement Verification 3.1 4.2 3.3 4.6.1, 4.6.15, 4.6.16 3.4.1 4.6.1 3.4.2 4.6.1,
32、 4.6.20 3.4.2.1 4.6.2, 4.6.3 3.4.2.2 4.6.1 3.4.3 4.6.9 3.5 4.6.6, 4.6.7, 4.6.10, 4.6.11, 4.6.14, 4.6.17 3.6.1 4.6.12 3.6.2 4.6.5 3.6.3 4.6.4, 4.6.8, 4.6.13, 4.6.18 3.6.4.1 4.6.9 3.6.4.2 4.6.9 3.6.5.1 4.6.1 3.6.5.2 4.6.19 3.6.5.3 4.6.1 3.6.6 4.6.1 3.6.8 4.6.21 3.6.9 4.6.1 4.6 Tests. 4.6.1 Examination
33、. The generator shall be examined for compliance with dimensions, weight, shaft hardness, connectors, mountings, markings, flexibility, and maintainability. 4.6.2 Continuity and resistance. The generator stator windings shall be checked for continuity between electrical connector pins A and B, and b
34、etween pins A and B and the generator case. The resistance between the pins or between a pin and the case shall be less than 50 ohms. These three measurements shall be within 2 ohms of each other. 4.6.3 Phase rotation. The generator terminals marked A and B shall be connected to the test indicator t
35、erminals marked A and B, respectively, while the indicator C terminal shall be grounded to the electrical connector shell. The test indicator shall indicate positive when the generator drive shaft is rotated in a counterclockwise direction. 4.6.4 Voltage. The generator shall be brought to a temperat
36、ure of 75 10F and the output connected to a standard load. The drive shaft then shall be rotated at 4,200 5 rpm. The three voltages, measured across the generator terminals, shall be 21 0.5. 4.6.5 Dielectric strength. The generator C lead shall be ungrounded and 500 V rms and 60 Hz Provided by IHSNo
37、t for ResaleNo reproduction or networking permitted without license from IHS-,-,-MIL-PRF-26611F 6 applied between pins A, B, and C, in turn, and the metal parts of the generator case (including the receptacle shell) for 5 seconds. There shall be no insulation breakdown as indicated by leakage curren
38、t in excess of 0.002 amp. 4.6.6 Low temperature operation. The generator shall be placed in a temperature chamber set to -85 10F for a minimum of 44 hours without rotating the drive shaft. After 44 hours, still at -85 10F, the shaft shall be rotated at 25 5 rpm for 15 1 minutes. The chamber temperat
39、ure then shall be raised to -50 10F and maintained for a minimum of 20 hours without rotating the drive shaft. After 20 hours at -50 10F, the drive shaft shall be rotated at 25 5 rpm. The breakaway torque shall not exceed 8 inch-pounds and the torque required to turn the shaft within the first minut
40、e of rotation shall not exceed 1.5 inch-pounds. 4.6.7 Vibration. Prior to vibration, the output voltage shall be measured in accordance with 4.6.4. The generator shall be mounted without vibration isolators directly to the vibration exciter. Tests shall be conducted under both resonance and cycling
41、conditions as specified in paragraphs 4.6.7.1 and 4.6.7.2. Time consumed performing 4.6.7.1 plus time consumed cycling in 4.6.7.2 shall equal 3 hours. Vibration displacement, velocity, and acceleration shall be measured at the specific instantaneous test frequency applied. Loose components that impa
42、ct each other resulting in a high “noise” content of the applied vibration shall be considered as vibration input. If such “noise” is encountered, a low pass frequency filter that cuts off at approximately twice the test frequency shall be employed to reject the “noise.” 4.6.7.1 Resonance test. Reso
43、nant nodes of the generator shall be determined by varying the frequency of applied vibration slowly through the specified range at vibrator accelerations shown in Table II. Individual resonant nodes surveys shall be conducted with vibration applied along each set of three mutually perpendicular axe
44、s of the generator. The generator shall be vibrated at the indicated resonant conditions for the times shown in Table III and the applied double amplitudes of vibrator accelerations in Table II. Vibration shall be applied along each of the three mutually perpendicular axes. If more than one resonanc
45、e is encountered when vibration is applied along any one axis, each resonance shall be sustained for the time shown in the applicable portion of the vibration test schedule. If more than four resonances are encountered with vibration applied along one axis, the four most severe resonances shall be c
46、hosen for test. TABLE II. Vibration data. Frequency (Hz) Displacement in double amplitude (inch) and Acceleration (g), if applicable 5 - 14 0.1 14 - 23 0.1 to 0.036 at 20g 23 - 104 0.036 104 - 2,000 0.036 to 0.001 at 20g 4.6.7.2 Cycling test. The generator shall be connected to the standard load and
47、 the drive shaft rotated at 4,450 250 rpm. While operating, the generator shall be vibrated in accordance with the vibration schedule in Table III. The frequency shall be varied logarithmically from 5 to 2,000 Provided by IHSNot for ResaleNo reproduction or networking permitted without license from
48、IHS-,-,-MIL-PRF-26611F 7 Hz and returned to 5 Hz in 20-minute intervals at an applied acceleration of 20g. After completion of testing in three axes, the output voltage shall be measured in accordance with 4.6.4. The generator, not operating, shall be subjected to 350F for a minimum of 1 hour. The g
49、enerator shall be removed from the oven and immediately vibrated (while operating) for 15 minutes. During the 15 minutes, the vibration frequency shall be cycled between 5 and 2,000 Hz one or two times, and the output voltage measured at this higher temperature in accordance with 4.6.4. The generator, not operating, then shall be subjected to 350F for a minimum of 1 ho
