TM
11-6130-243-14-3
CHAPTER 4
FUNCTIONING OF EQUIPMENT
4-1. Input Circuit
lamp LI and metering circuitry.
b. Transformer T1 has two 3-phase secondaries,
one in delta configuration and one in wye configura-
The power supply is designed to operate from either
tion. The output of each secondary is converted to
220- or 440-volt, 60Hz, 3-phase power. The input cir-
direct current by CR1 and CR2, which are 3-phase
cuit consists of three electrical parts and the primary
f u l l - w a v e bridge rectifiers. The interphase
winding of power transformer T1. The three electrical
transformer T2 permits continuous flow from each of
parts are circuit breaker CB1, switch S1, and switch
the rectifiers by preventing each rectifier from bias-
S2. Circuit breaker CB1 protects the unit in the event
ing the other off. Each rectifier has a ripple frequency
of overcurrent, and turns the unit on or off. Switch S1
of 360 Hz. The output currents of the two rectifiers are
changes the taps on the transformer to allow the out-
combined in transformer T2, yielding a ripple fre-
put voltage to be adjusted to 28 25 volts. Switch S2
quency of 720Hz. Bleeder resistor R1 improves
changes each of the three sets of windings on the
regulation characteristics by decreasing the voltage
power transformer from series to parallel to permit
drop from no load to full load. Filter capacitor Cl
operating at 440 or 220 volts. Transformer T1 has six
decreases ripple by removing high frequency com-
windings on the primary, three of which have multi-
ponents from the output, L1 is a 28 volt indicator
ple taps. The windings are connected in delta-series or
light across the output.
delt-parallel depending on the position of Switch S2.
4-2. Output Circuit
M2 and a current measuring circuit, When current
flows through meter shunt R2, a voltage appears
across it which is proportional to the current flow.
a. The output circuit consists of the secondaries of
Potentiometer R3 and resistor R4 provide meter ad-
power transformer Tl, full wave rectifiers CR1 and
justment and current limiting for ammeter Ml,
CR2, an interphase transformer T2, a bleeder resistor
which is across the meter shunt R2.
Rl, and a filter capacitor Cl along with an indicator
4-1
