MIL-DTL-52876D
APPENDIX A
TEST METHOD 3
5 ZONE POWER SUPPLY
FUNCTIONAL TESTS
1.
TEST APPARATUS:
a.
Oscilloscope (Scope)
Tektronix model 2225 or equivalent.
b.
Voltmeters, dc (M2, M3, M4)
3-1/2 digit or greater, minimum accuracy
0.25 percent of reading ± 1 LSD.
c.
Voltmeter, ac (M1, M5)
3-1/2 digit or greater, minimum accuracy
1 percent of reading ± 1 LSD.
d.
Power supply (PS1)
Hewlett-Packard Model 6291A or
equivalent.
e.
Autotransformer (VR1)
General Radio Model W20M or equivalent.
f.
SPST switches (S1-S7)
Leviton Model 19916 or equivalent.
20K ohms, ±5 percent, 1/4 watt.
g.
Resistor, 20 Kilohm (R1)
h.
Resistor, 32 ohm (R2)
Ohmite, 50 ohm, adjustable, 50 watts,
type 210-50, P/N D50K50R or equivalent.
i.
Resistor, 16 ohm (R3)
Ohmite, 25 ohm, adjustable, 50 watts,
type 210-50, P/N D50K25R or equivalent.
j.
Resistor, 150 ohm (R4)
Ohmite, 200 ohm, adjustable, 12 watts,
type 210-12, P/N D12K200 or equivalent.
k.
Resistor, 7.5 ohm (R5)
Ohmite, 10 ohm, adjustable, 225 watts,
type 210-225, P/N D225K10R or equiv.
l.
Ammeter, dc (see note)
3-1/2 digit or greater, minimum accuracy
0.75 percent of reading ± 1 LSD, 4
amperes minimum.
m.
Test fixture
(See figure 2).
Note:
Item l. is required only for calibrating test fixture resistors.
2.
TEST PREPARATION:
2.1 When this test is being performed as part of the monitor cabinet
functional test remove the power supply from the cabinet prior to performing
the test procedure.
3.
TEST PROCEDURE
3.1
Output voltage levels.
a.
Connect the power supply under test (PSUT) in the test fixture as show
in figure 2. Set PSUT power switch in the "OFF" position and apply 117
Vac, 60 Hz line power to the autotransformer (VR1).
b.
Open S1 through S7.
c.
Adjust the VR1 for 117 Vac on M5.
d.
Close S4.
e.
Place the power supply under test power switch in the "ON" position.,
Allow at least 15 minutes warm up before proceeding with test.
f.
The following output voltage levels shall be observed:
Location
Meter
Voltage
Output
20 ±1 Vdc
1
TB3-2 to TB3-5
M2
2
TB2-4 to TB2-1
M3
See below
22.5 ±3.5 Vac
3
TB3-1 to TB3-6
M1
Output 2: 28.2 ±0.3 Vdc at 77 ±5 °F; 30.8 ±0.7 Vdc at-20 °F; 26.6 +0.7 Vdc
at +150 °F; 27.9 ±0.5 Vdc during humidity test.
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