MIL-PRF-1/1361H
TABLE I. Testing and inspection - Continued.
1/
Instantaneous starting is not recommended. When it is necessary, the maximum permissible epy is 22 kv and it shall not be
attained in less than 0.04 second.
In pulsed operation, the peak inverse voltage shall not exceed 5.0 kv during the first 25 µs following the pulse.
2/
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 tests shall be performed in accordance with MIL-STD-202, method 213, except as noted. The tube shall be mounted
on suitable rigid fixtures in the positions described below by means of its mounting flange. The tube shall not be clamped,
braced, or supported by means other than its mounting flange.
The tube shall be subjected to three blows in each of the following positions:
Position of tube in elevator assembly
Intensity and duration of blow
Vertical: Base down
80 G, 11 ms, half-sine shock pulse
Horizontal: Center line through heater terminals, vertical
60 G, 11 ms, half-sine shock pulse
Horizontal: Center line through heater terminals, horizontal
60 G, 11 ms, half-sine shock pulse
The tests shall be performed with both heater and reservoir at substantially full operation temperatures. Means for detecting
heater current variations and shorts between anode and grid and between grid and cathode shall be provided. No temporary
or permanent changes in heater or reservoir currents or temporary or permanent shorts between electrodes shall occur.
5/
Standby operation, with heater and reservoir voltage on, is not recommended. Where 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.
Maintain grid seal temperature within 225°C above ambient temperature by blower directed at seal and lower ceramic
6/
cylinder. Approximately 15 cfm of air is required at rated power levels.
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) conditions 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.
Adjust reservoir voltage to value indicated on the tube within ± 5 percent, except as otherwise specified.
9/
10/
The anode circuit constants shall be chosen so that at epy = 33.0 kv; under resonant charging conditions; ib = 2,000a
minimum; dik/dt shall be 10,000a/µs minimum; tp = 2.5 ± 10 percent µs; prr = 500 minimum. Grid pulse measured at tube
socket with thyratron grid disconnected: tr = 0.35 µs minimum, tp = 2.0 µs maximum; internal impedance of driver: 75 ohms
minimum.
11/
This test is to be the first test performed at the conclusion of the instantaneous starting test.
12/
The tube shall be capable of operating under the following conditions:
a.
Apply cathode heater voltage and adjust reservoir voltage to 95 percent of the optimum reservoir voltage and allow both
to warmup for 15 minutes.
b.
Raise anode voltage directly to the specified voltage at a rate of not less than 30 kv per minute.
c.
The tube shall operate at the specified anode voltage for a total of 2 hours which may include one interruption. A total of
four interruptions at any anode voltage is permitted provided that the total test time required to perform this part of the
operation test does not exceed 135 minutes.
d.
After the above operation is at full anode voltage, increase the reservoir to 105 percent of the optimum value. The tube
shall continue to operate for an additional 2 hours with not more than one interruption.
e.
After the above operation at full anode voltage, decrease the reservoir voltage to optimum value. The tube shall continue
to operate for an additional hour without interruption.
4
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