MIL-PRF-1/1658C
TABLE I. Testing and inspection - Continued.
1/
Instantaneous starting is not recommended. W hen it is absolutely necessary, the maximum permissible epy is 22 kv and it shall not
be attained in less than 0.04 second.
2/
In pulsed operation, the peak inverse voltage shall not exceed 5.0 kv during the first 25 µs following the pulse.
3/
The driver pulse, measured at the tube socket with thyratron grid disconnected: 1,300 volts minimum; 2,500 volts maximum; tr =
0.35 µs maximum; grid pulse duration 2.0 µs minimum. Impedance of drive circuit 10 to 25 ohms.
4/
Shock and vibration tests.
(a)
Shock tests. Shock tests shall be performed in accordance with MIL-STD-202, method 205, except as noted. Shock
machines of the same type as specified but with rubber impact pads for more reproducible shock acceleration patterns may be
used. The tube shall be mounted on suitable rigid fixtures in the position described below by means of its mounting flange.
The tube shall not be clamped, braced, or supported by means other than its mounting flanges.
The tube shall be subjected to three blows in each of the following positions:
Position of tube elevator assembly
Intensity and duration of blow
Vertical - base down
50 G, 11 ms
Horizontal - center line through heater terminals, vertical
50 G, 11 ms
Horizontal - center line through heater terminals, horizontal
50 G, 11 ms
The tests shall be performed with both heater and reservoir at substantially full operating temperatures. Means for detecting
heater current vibrations and shorts between anode and grid and between grid and cathode shall be provided. No temporary or
permanent change in heater or reservoir currents or temporary or permanent shorts between electrodes shall occur.
(b)
Vibration tests. Vibration tests shall be performed as specified in MIL-STD-202, method 201. Tube shall be vibrated as
described for 2 hours each in the vertical direction, in the horizontal direction parallel to the heater connections, and in the
horizontal direction perpendicular to the heater connections.
(c)
After shock and vibration tests, the tube shall meet all the conformance inspection, part 1 and part 2 test requirements. An
aging period not to exceed 1 hour is permitted after mechanical tests.
(d)
The anode terminal extension may be removed during performance of the shock and vibration tests.
(e)
For the purpose of defining a production "lot", quantities of types 7390 and 8789 produced concurrently, shall be combined to
constitute a "lot". Tests may be performed prior to installation of permanent leads and adaptive mounting plate.
5/
Standby operation, with heater and reservoir voltage on, is not recommended. W here standby operation is necessary, provisions
shall be made to operate the tube at full equipment conditions for a minimum of 2 hours during each 12-hour period of standby.
6/
Cooling is preferred at high duty conditions.
7/
Approximately 15 cfm of air may be directed at grid seal and lower envelope.
8/
The optimum reservoir voltage for operation in accordance with operation (1) condition is inscribed on the base of the tube and must
be held within ± 2.5 percent. Applications involving other operation conditions will necessitate the re-determination of the optimum
reservoir voltage.
9/
Except as otherwise specified, adjust reservoir voltage to value indicated on the tube within ± 5 percent.
4
For Parts Inquires call Parts Hangar, Inc (727) 493-0744
© Copyright 2015 Integrated Publishing, Inc.
A Service Disabled Veteran Owned Small Business