The following components and equipment
are needed for the adjustment procedures
on the voltage regulator.
DC Voltmeter + 0.5 percent, 0-100 VDC (M 1
AC Voltmeter + 0.5 percent, 0-150 VAC (M2)
Voltage source 0-150 VAC 60 Hz, Regulation +
0.25 percent, from 0-2 Amps (PS )
Resistor 30 ohms, 120 watts (R1)
Resistor 750 ohms + 5 percent 2 watts (R2)
Potentiometer, 500 ohms (R6)
Connect voltage regulator, equipment, and
components as shown in Figure 7- 16.
Set potentiometer R6 to 250 ohms
Turn AC power supply (PS 1) on.
Figure 7-12.4. Voltage Regulator Adjustment Schematic.
Slowly increase AC voltage (O to 30 VAC)
while monitoring DC voltmeter (M 1) and
oscilloscope (M3). DC voltage reading on
proportionally with the increasing AC
voltage and the voltage wave form trace
of oscilloscope (M3)
shall move toward a positive voltage level.
A voltage shall also be indicated on meter
DC voltmeter (M4). The waveform trace
of oscilloscope (M3) swinging below the
zero axis (negative) during this (0-30
VAC) test shall be indicative of an
unusable/defective operational amplifier.
Increase AC voltage for a "maximum
reading" on meter (M 1) (35 VDC
minimum) or until oscilloscope (M3)
waveform is just starting to come off the
"maximum level" refer to curve 1 of Figure
Figure 7-12.5. Waveforms.
If the AC voltmeter (M2) indicates 136
VAC or greater, proceed with step (7).
If the AC voltmeter (M2) indicates less
than 136 VAC, proceed with step (8).
Adjust AC supply (M2) to 136 VAC.
oscilloscope (M3) waveform begins to
decrease from "maximum level". DC
voltmeter (M I) reading shall go to zero
when waveform passes through zero.
Refer to curve 2 on Figure 7-17.
Adjust AC input voltage AC voltmeter (M2)
to 133 VAC. The oscilloscope (M3)
waveform shall return to maximum level
and DC voltmeter (Ml) shall read
maximum (35 VDC minimum).
Adjust AC supply (PS1) to adjust (M2) to
Change 8 7-14.5