MIL-PRF-19500/446E
* 4.4.3.1 Group C inspection, table E-VII of MIL-PRF-19500.
Subgroup
Method
Conditions
C2
1056
Not applicable.
C2
2036
Test condition A, 6 pounds, t = 30 seconds.
C2
2036
Test condition D1, t = 10 seconds, 5 inch-pounds.
C2
1071
Not applicable.
Pressure = 8 mm Hg; IR = 2.0 A dc maximum, VR = rated VRWM (see 1.3), (applied
C5
1001
between all terminals to the case), t = 60 seconds.
VRWM = 0 V, bridge IO = 25 A dc (entire bridge biased); TC = 55C + 10C,- 0C;
C5
4066
IFSM = 150 A (pk) (each device for each bridge leg); tp = 8.3 ms; ten surges for each
leg at maximum 1 minute intervals; n = 22, c = 0.
Alternate condition: Each leg may be biased separately to IO = 12.5 A dc. All other
conditions are the same as above.
IO = 0 A dc; TA = 150C; VRWM = 80 percent rated VRWM (see 1.3), f = 60 Hz.
C6
1026
4.5 Methods of inspection. Methods of inspection shall be as specified in the appropriate tables and as follows.
4.5.1 Dielectric withstanding voltage. This test shall be performed with the metal case of the assembly connected
to ground and all terminals connected to the high potential side of a dc power supply or a scope display test set. The
voltage applied between the terminals and the case, shall be 2,800 volts dc. Any discontinuity or dynamic instability
of the trace, or a breakdown current in excess of 10 A dc, shall be cause rejection.
4.5.2 Junction temperature test. This test shall be performed in accordance with method 3105 of
MIL-STD-750. The maximum junction temperature for any diode in the bridge at the below specified conditions shall
be 175C maximum. The test conditions shall be as follows:
a. TC = 55C
TC = 100C.
or
b. IO = 25 A dc,
IO = 15 A dc.
c. Iref = 10 mA dc,
Iref = 10 mA dc.
4.5.3 Thermal impedance. VF measurement shall be performed in accordance with method 3101 of
MIL-STD-750. The following parameters shall apply: (1) Measurement current (IM): 10 mA; (2) Heating
current (IH): 10 A minimum; (3) Heating time (tH): 10 ms; (4) Measurement time delay (tMD): 70 s
maximum. The maximum limit for ZJX under these test conditions is 1.5 C/W.
4.5.4 Operational thermal cycling. This test shall be performed by connecting a single phase 50 - 60 Hz sine wave
input to the ac terminals of the bridge. The resistive load or input voltage shall be made variable in order to maintain
a rated bridge output current of 25 A dc. Bridge case temperature shall be maintained at 55C except during the
cooling cycle when case temperature shall be permitted to drop 20C maximum. Life-test duration shall be 2,000
cycles with a heating time of 8 minutes, +10, -0 minutes and a cooling time 2 minutes.
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