regulated rectifier is controlled with three
MK 19 MOD 3B GYROCOMPASS
silicon-controlled rectifiers. A dc filler is
incorporated to smooth the output to the
The Mk 19 Mod 3B gyrocompass system is
identical to the Mk 19 Mod 3A system with the
Two sensing circuits consisting of several
exception of a few changes. The Mk 19 Mod 3B
resistors and a battery charging voltage
system uses a static standby power supply
potentiometer are also included in the charger.
instead of a motor-generator standby supply.
These components automatically sense charging
This standby power supply is considerably more
current and voltage, and send a signal to the
reliable than the motor-generator type since the
battery charging regulator.
only moving parts are the three relays used in
the sensing circuits.
The battery charging regulator receives its
po w e r f r o m a se c o n d w y e - w o u n d se c o n dar y o f
Figure 4-39 is an open-door view of the 3B
the input transformer (a neutral is not used).
standby power supply. The unit supplies a
The output of the transformer is rectified to
highly reliable 3-phase, 400-Hz, 115-volt, line-to-
36 v olts dc. In the battery -charg ing reg ulator,
line power from a 3-phase, 400-Hz, 115-volt or
comparison is made between the sensing
from a 120-volt dc source. For explanation,
circuit output and the second transformer
figure 4-40 is divided into two sections: a battery
se c o n dar y o u tpu t in th e c o n tr o l w in din g s o f
charger and an inverter. The battery charger
the reactor in the regulated rectifier. In this
will be discussed first.
manner, the firing of the silicon-controlled
rectifiers of the regulated rectifier are
The input transformer is a delta-wye, 1 to 1
controlled. By controlling the tiring of the
voltage ratio supplying approximately 110 volts
silicon-control rectifiers, the output of the
ac line-to-line on the secondary and 64 volts ac
regulated rectifier is controlled.
line-to-neutral. The wye secondary is used to
take advantage of the neutral.
A relay is used to delay connection of the
batteries to the charger until rated output is
The input transformer supplies a 3-phase,
full-wave rectification circuit. The firing of the
Figure 4-39.--Standby power supply, door open.