TM 11-5820-765-34
TEST EQUIPMENT SETTINGS:
Control: 115 volts
FUNCTION switch: AC VOLTS, 250 VOLT SCALE
B l a c k test lead: OHMS DC + AC jack
R e d test lead: 2.5 jack, 1000 OHMS PER VOLT
AC DC column
AN/USM-98A
Range: 50 volt
Null: VTVM
Voltmeter ME-30(*)/U
Switch: 0.3 volts (calibrated)
Load
0.56 ohm, 1000-watt resistor
Test
switch
Open
NOTE
Keep test equipment at these settings except where noted.
Circuit breaker CB1 ON.
(1) Equipment set as noted above.
Set dc voltage adjust R4 for 28-volt output.
Less than 1.0 volt difference between readings.
1
Check accuracy of voltmeter
Ml;
compare
AN/USM-98A readings.
Voltage within 1% rms (approximately
3%
peak
2 Close test switch. Check ripple voltage
to peak) of output voltage.
on ME-30(*)/U.
Reading within +0.5% of 28 volts dc (maximum
3 Check dc output voltage on AN/USM-98A.
voltage deviation 280 millivolts or less).
DC voltage: 28 volts.
(2) Transformer: 127 volts.
Reading within +0.5% of 28 volts dc (280 mV or
Test switch closed.
less
deviation).
Check dc voltage output on AN/USM-98A.
DC voltage adjust: 28 volts.
(3) Load: 1.3 ohm, 1000-watt resistor.
Test switch closed.
Reading within +0.5% of 28 volts dc (280 mV or
Check dc output voltage.
less deviation).
