TM 11-6130-266-15
CHAPTER 4
FUNCTIONING
e. The output of the preregulator switch is
4-1. Block Diagram
integrated by a filter composed of inductor L1 and
capacitors A8C2 through A8C5 to provide a low-level
a. The power supply provides a regulated 24 to 32-
ripple dc voltage which enables high efficiency operation
volt dc output required to operate an electronic
of the pass element. The filtered output is applied to the
equipment or to charge an external battery. The power
series pass element.
supply will maintain a constant output voltage within 1
percent. The operating power for the power supply is
f. The post regulator comprises a conventional
115 or 230 volts at a frequency of 50, 60, or 400 Hertz.
pass element control gate for controlling the output
voltage. This gate is controlled by voltage regulating
b. The ac input voltage is applied, through AC input
amplifier A2Q3 (balanced differential amplifier).
circuit breaker CB1, to main transformer T1. The
Changes in output voltage result in a proportional error
outputs at the secondary windings of transformer T1 are
voltage change to the amplifier. The resulting error
fed to both the power regulator switch (in preregulator
voltage will correct the output to its preset level. The
assembly A4) and to the auxiliary power supply (in
output of the series pass element is fed to energy
auxiliary supply and control assembly A1). Also, AC
storage capacitor A8C6 where high frequency transients
indicator lamp DS1 is lighted.
are reduced and the regulator stability is improved.
c. The preregulator provides high efficiency
g. The post regulator also contains output current
isolation between the series pass element and any input
sensor resistor A6R1 and current regulating amplifier
line variations. The preregulator circuit consists of two
A2A1 which limit the load current to a safe
silicon controlled rectifiers A4Q1 and A4Q2, pulse-width
predetermined level. The load step compensator
controlled by phase angle control A4A1L1 (part of
differentiates the output of A2A1 so that in the event of a
magnetic amplifier A4A1). Gating signals for phase
step load, it provides a large turn-on pulse for phase
angle control A4A1L1 are provided by gate generator
angle control A4AL1. This large pulse eliminates the
A4A2, A4A1T1. The control windings are referenced to
drooping response characteristic inherent in a magnetic
the series pass element drop of the post regulator by the
amplifier.
comparator. Any change in the series pass element
drop results in a proportional error current in the control
h. The output circuit includes power transfer relay
windings and automatically corrects the series pass
A6K1 which connects the output termination to an
element drop to the preset level. The transient
external battery in the event of a drop in line voltage.
suppressor provides means for dissipating excess
Sensing transfer relay A1K2 disconnects remote
energy in filter capacitors A8C2 through A8C5 when a
sensing, while relay A1K1 is used for the standby
drive signal is received from the comparator.
condition. The DC circuit breaker CB2 connects the dc
output voltage to the load and also serves as a
d. The auxiliary power supply provides the
protective device. The DC OUTPUT ADJ potentiometer
regulated +16 and -16 volts dc necessary to meet the
R3 is used to adjust the output voltage of the power
low-level power requirements of the preregulator and the
supply. Indicator lamps DS2 (NORM) and DS3 (EMER)
post regulator. In addition, a full wave bridge rectifier
are also provided to indicate the operational status of the
circuit in auxiliary supply and control assembly Al
unit. OUTPUT METER M1 indicates both voltage and
provides an unregulated nominal +32 volts dc for
current of the post regulator, as determined by the
operation of the transfer control circuit. This circuit
setting of VOLTAGE-CURRENT selector switch S2, or
senses input line conditions.
only the voltage of an external battery supply.
4-1
