control magnet valves power and control fingers and an
drum is free to revolve on the main shaft and is
insulating base.
operated by the REVERSE lever which is located below
the THROTTLE lever.
c. To operate the reverser it is only necessary to
c. The drums are so interlocked that the
complete the circuit from the battery through one of the
THROTTLE lever cannot be operated unless the
magnet coils. The current in the coil magnetizes the
REVERSE lever is in the ENGINE ONLY, FORWARD
core to pull down the armature and open the valve, thus
or REVERSE positions and the REVERSE lever cannot
admitting air to one of the cylinders to turn the drum.
be operated unless the THROTTLE lever is in the OFF
d. The reverser drum is divided into two parts.
position.
The larger section, which handles the main motor
d. Motion of the THROTTLE lever changes the
current, is provided with heavy copper segments which
engine throttle setting to increase or decrease the
make contact with stationary fingers mounted on each
engine speed by means of a throttle operating device
side of the drum. The smaller section, which handles
which is mounted on the engine and energized through
only the low voltage control circuits, is provided with
the controller, and establishes the control circuits to
light copper segments which make contact with small
actuate various switches which are employed for
fingers on each side. The object of these interlock
operating the traction motors.
The reverse drum
fingers.
controls the operation of the reverser and the energizing
as they are called, is to provide an interlock between the
of the control circuits from the battery.
reverser drum and the circuit for operating the power
switches.
be lubricated occasionally with a few drops of light
e. A handle is provided on the end of the reverser
machine oil.
shaft so that it can be operated by hand in cases of
f. The REVERSE handle is removable in the OFF
emergency or during inspection.
position only and serves as a means of locking the
f. The interlocking of the control circuits with the
controller when not in use. Refer to paragraphs 86
reverser is such that the drum contacts do not break the
through 96 for maintenance instructions.
motor current. Any sign of arcing on the drum indicates
either weak finger pressure or faulty operation. The
14. Reverser
drum contacts should be kept clean and smooth with the
aid of fine sandpaper. The contacts should be wiped
a. The reverser functions to reverse the
perfectly clean after they are smoothed, and particular
connections between the fields and armatures of the
care should be exercised to see that no grit is lodged
traction motors and prescribe movement of the
under the fingers.
locomotive either FORWARD or BACKWARD.
b. The reverser consists of a drum (with insulated
copper segments) capable of rotation through a small
angle, two air cylinders with pistons for drum rotation,
Section III. DETAILED FUNCTION OF EQUIPMENT
15. Generating Equipment and Control Devices
d. Voltage Regulator Panel.
(1) The regulator is a sensitive voltage relay
by the engine and supplies current for the operation of
which controls the auxiliary generator
the traction motors during running periods; it is also
voltage for charging the battery by varying
used as a motor operating from battery current to start
the field current in its shunt field circuit. It
the engine.
maintains approximately constant voltage
over the auxiliary generator speed and
b. Auxiliary Generator. The auxiliary generator
load range.
furnishes power for battery charging and for all electrical
auxiliaries. It is under the control of the voltage
(2) The reverse current relay is located on the
regulator.
right side of the panel and controls the
auxiliary generator battery charging
c. Engine Starting Contactors.
Magnetic
contactors G, G1 (and G2) establish engine starting
circuits from the battery to the main generator and its
series starting field.
6
