TM 11-6130-392-34
CHAPTER 2
FUNCTIONING OF THE EQUIPMENT
2-1. GENERAL
The Battery Charger PP-7286/U is a portable, self-
a. Prime power supply and controls. Prime
contained unit with attached power cable. The equip-
power enters through a power cable. EMI filters
ment functions as a convenient means for charging
(FL1 & FL2), on each side of the source power
various types and sizes of sealed nickel-cadmium bat-
line, prevent radio frequency interference with
teries, using convenient ac input power sources. Five
battery charger operation. The filters are followed
batteries, all similar or assorted types, may be charged
by an interlock (S6) which interrupts prime power
at the same time using the controlled dc output provided
for safety, when the cover is removed from battery
by the battery charger. The Battery Charging Tray
charger. Prime power is controlled by combined
Assembly MX-10154/U is a portable self-contained unit
circuit breaker/power switch (CB1) and interlock
with attached power cable. It is used in conjunction with
switch (S6), providing manual on-off and auto-
Battery Charger PP-7286/U and furnishes a means of
matic trip-off protection if input current exceeds
charging one through six sealed nickel-cadmium bat-
10 amperes. Dc power for all functions, 10 and 62 vdc
teries, BB-503/TAS, from a constant current source
nominal, is provided by components of the power
s u p p l i e d by the battery charger. Refer to TM
supply and input voltage select group which include:
maintenance manual, for controls, indicators, and
operating instructions for the battery charger and the
(1) Transformer (T1) capacitor (C1) and
battery charging tray assembly.
diode bridge (A14-CR1) provides 62 vdc to the
five charging circuits.
2-2. Block Diagram Analysis of the Battery
(2) Power supply assembly (A11), provides
Charger
regulated 10 vdc to the timing circuit.
An overall block diagram (fig. 2-1) shows the operating
(3) Input voltage, 115 or 230 vac, is man-
relationship of the battery charger components, and
ually selected by switch (S1) and power-on status
groups the components within major circuit-and-
indicated by lamp (DS1).
control functions.
2-3. Principle of Operation
Timing circuit and controls. The timing
b.
circuit controls charging time. Timing circuit
When START TIME switch (S2, in Timing Circuit
assembly (A12) computes and displays remaining
block) is pressed, the battery charger supplies a
time the battery charger will operate, without
preset charging current to the batteries connected
being reset, before automatic shut-off. Display circ-
to J1 through J10. The battery charger will auto-
uit (A13) counts down and shows remaining time-
matically shut off at the end of preset charging
to-operate. Thumbwheel switch (S3) is used to set
cycle. The charging current value and charging
charging time. Pushbutton switch (S2) is used to
time are determined by control settings made by
start timing circuit operation. If prime power is
the operator of the equipment.
interrupted the timing circuit power is taken from
a 9 volt battery (B1) inside battery charger. Battery
2-4. Circuit and Control Functions
powered logic holds the count, timing circuit re-
starts and charging continues when prime power
Circuit and Control functional descriptions, referenced
returns.
to components shown within a functional block (fig.
Change 1 2-1
