1、AMSC N/A FSC 5960 INCH-POUND MIL-PRF-1/1512C 2 December 2008 SUPERSEDING MIL-E-1/1512B (USAF) 29 January 1971 PERFORMANCE SPECIFICATION SHEET ELECTRON TUBE, POWER TYPE 7248 This specification is approved for use by all Depart- ments and Agencies of the Department of Defense. The requirements for acq
2、uiring the electron tube described herein shall consist of this document and the latest issue of MIL-PRF-1. DESCRIPTION: Tetrode See figure 1 Mounting position: See note 2 Weight: 2.5 pounds nominal ABSOLUTE RATINGS: Parameter: Ef Ebb eb Ec1 Ec2 ik Pg1 Pg2 Unit: V kVdc kV Vdc Vdc a W W Oil immersed
3、6.3 5% 125 (See note 1)125 -600 1,500 2.0 10 20 TEST CONDITIONS: 6.3 - - - 1,000 - - - ABSOLUTE RATINGS: Parameter: Pp Glass temp Insulation and cooling T ( coolant) Unit: W C - C Oil immersed 200 150 (minimum) See note 2 75 (See note 5) Air insulation: - 150 See note 3 - Test Conditions : - - See n
4、ote 4 - GENERAL: Qualification Not Required. Inactive for new design after 5 December 1997. Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-MIL-PRF-1/1512C 2TABLE I. Testing and inspection. Limits Inspection MIL-STD-1311 Method Conditions AcceptanceL
5、evel 12/ Symbol Min Max Unit Conformance inspection, part 1 Positive grid drive High-voltage stability Electrode voltage (grid) - - 1261 Ec1 = -150 Vdc; ec1 = 200 v; Ebb = 2,00 Vdc; tp = 160 s (max) prr = 15 (max) (See note 6) Ec2 = Ek =0; Ec1 = -500 Vdc; Ebb = 125 KVdc; Rp = 1.0 Meg (max) t = 30 mi
6、n (max) (See note 7) Ebb = 125 KVdc; Rp = 1.0 Meg (max) Ec1/Ib+20 Adc (See note 8) 0.65 0.65 0.65 ic1 ic2 ib - Ec1 - - 900 - - 140 250 1,570 - - 420 ma ma ma - Vdc Conformance inspection, part 2 Filament current Total grid current 1301 1266 Ef = 6.3 V (See note 4) Ebb = 1,200 Vdc; Ec1/ib = 0.165 Adc
7、; Ic2 = 0.02 Adc (max); t = 5 minutes (see notes 9 and 10) - - If Ic1 10.0 - 13.5 - 50 A AdcQuality conformance inspection, part 3 Peak emission (See note 11) 1231 Ec1 = ec2 = eb = 400 V Ec1 = ec2 = eb = 2400 V - is is 1.5 5.0 3.2 - A A NOTES: 1. When the tube is first installed, or after tube has b
8、een inoperative over a period of time, anode voltage, when first applied, shall be increased gradually from 75 kV to 125 kV, over a 10- minute period, in accordance with the manufacturers recommendations. Warning: Operation of this tube may produce X-ray radiation. Adequate radiation protection shie
9、lding shall therefore be provided. 2. When immersed in oil horizontally, the tube will be cooled by natural convection. When the tube is operated vertically in oil, the re-entrant portion of the cathode end of the tube shall be cooled by forcing oil through the center pin No. 5 of the cathode base b
10、efore and during the application of filament voltage at a minimum flow of 3 pin per minute. For oil insulation, the tube shall be immersed in a high-grade, low-viscosity insulation oil having a dielectric strength not less than 25,000 peak volts/0.1 inch when tested per ASTM test D-877. 3. When the
11、tube is air tested and the tube is in any position, the re-entrant portion of the cathode end of the tube shall be cooled by forcing air thought the center pin No. 5 of the cathode base before and during application of filament voltage at a minimum flow rate of 1-1/2 cfm. 4. All test to be performed
12、 with the tube immersed horizontally in insulating oil as described in note 2. Filament current test may be done in air as described in note 3. Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-MIL-PRF-1/1512C 35. Coolant temperature indicated is avera
13、ge temperature of oil surrounding tube and temperature of incoming oil to cathode when mounted vertically. 6. The positive pulse voltage, ec1, is measured between control grid and cathode. The amplitude of the voltage and current pulses shall be measured approximately at the middle of the pulse. 7.
14、This test may be preceded by an aging period at reduced anode voltage of a duration not exceeding 10 minutes. The tube shall operated during the last 10-minute period with no more than two flashes. Total test time, excluding aging, not to exceed 30 minutes. Flashes shall be interpreted as luminescen
15、ce within the vacuum space of the tube. Fluorescence of the glass surfaces of the tube shall not be considered a flash. Flashes may be counted by an electronic device, operation of which is based on the anode current surge which accompanies the flash. 8. Read Ib at Ec1 = -500 Vdc. Then make Ec1 less
16、 negative to the point where Ib increases by the indicated amount. 9. If impossible to obtain 0.165 ampere anode current without exceeding 0.020 ampere screen current, it shall be permissible to adjust anode voltage until such conditions are obtained provided no rating are exceeded. 10. To be perfor
17、med prior to positive grid drive test. 11. The number of tubes to be tested shall be one percent of each month of each months production, but not less than one nor more then three tubes shall be tested. 12. This specification sheet utilizes an accept on zero defect sampling plan in accordance with M
18、IL-PRF-1, table III. Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-MIL-PRF-1/1512C 4FIGURE 1. Outline drawing of electron tube type 7248. Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-MIL-PRF-1/15
19、12C 5Dimensions are in inches with metric equivalents (mm) in parentheses Ltr Minimum Maximum Conformance inspection, part 2 A 9.562 (242.87) 9.938 (252.43) B 3.625 (92.08) C 2.625 (66.68) D 3.00 (76.20) 3.063 (77.80) E 1.812 (46.02) 1.936 (49.17) F .625 (15.88) G .969 (24.61) 1.031 (26.19) H 1.188
20、(30.18) 1.438 (36.53) J 1.063 (27.00) 1.125 (28.58) K .719 (18.26) .781 (19.84) L .594 (15.09) .656 (16.66) M .370 (9.40) .380 (9.65) N .432 (10.97) .442 (11.23) P 2.490 (63.25) 2.510 (63.75) R 58 62 S 28 32 T 118 122 NOTES: 1. Inlet tube for forced oil or air cooling (.156 inch (3.96 mm) I.D.). 2.
21、Four pins located on circle diameter P. FIGURE 1. Outline drawing of electron tube type 7248. Continued Referenced documents. In addition to MIL-PRF-1, this document references the following: MIL-STD-1311 ASTM-D877 Marginal notations are not used in this revision to identify changes with respect to
22、the previous issue due to the extent of the changes. Custodians: Preparing activity: Air Force 85 DLA- CC DLA- CC Project number (5960-2008-072) Review activities: Air Force 99 NOTE: The activities listed above were interested in this document as of the date of this document. Since organizations and responsibilities can change, you should verify the currency of the information above using the ASSIST Online database at http:/assist.daps.dla.mil. Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-
