59. Failure of Battery Charging
b. Check for broken or loose wiring at the resistors.
Failure of battery charging as indicated by the
Check closing of battery charging contactor.
battery ammeter may be due to:
c. Check wiring and fingers at terminal boards,
a. Blown charging fuse.
controller, throttle device, etc.
b. Improper voltage regulator operation.
d. Check line switches to insure that they close
properly with good contacts. Failure of line switches to
c. Burned-out auxiliary generator field resistor.
close may be due to poor finger of interlock contact at
d. Open circuits in wiring.
reverser or controller of failure of reversal to throw to
correct position.
60. Compressor Fails to Pump Up Air
57. Complete Failure of Electrical Power
If the compressor does not operate properly check
as follows:
be due to the failure of the field switches to close,
a. Check angle and drain cocks, piping, air hose,
burned out resistors in the main or auxiliary generator
magnet valves, safety valves and other points for
field circuits or open circuits elsewhere in the field
leakage. Check for faulty compressor drive.
circuit.
b. Failure of Reverser to Throw (Pneumatic
failure to maintain pressure, excessive operation of
Types). Throw reverser by hand.
compressor and overheating. Refer to TM 55-2034 for
c. Open Circuit in Control Wires. Check fingers on
maintenance instructions.
controller, interlock fingers on the reverser and control
wiring connections.
61. Common Causes of Faulty Operation
d. Faulty Contactor Operation. May be due to too
Some of the most common causes of faulty
wide an air gap on magnetic switches, or binding which
operation of switches, control and motors of the auxiliary
prevents free movement and good contact.
and main apparatus are:
a. Interlocks and Control Fingers.
Improper
58. Miscellaneous Troubles
contact at interlocks and control fingers caused by dirty
a. If the engine is running at full speed and load,
gummy contact surfaces due to use of heavy oil,
and the locomotive does not make its usual speed, the
burning (oxidation) and improper adjustment.
trouble may be due to: dragging brakes, airbrake not
b. Contractors. Too wide an air gap (contact
fully released, head winds, or hot truck journal bearings,
opening) resulting in an unnecessarily high closing
or traction motor axle or armature bearings.
voltage, binding at bearings, loose shunts or loose
b. Do not operate with inadequate supply of
springs. Low control pressure or leaky valves on
lubricating oil nor with insufficient cooling water. Watch
remotely operated devices.
for excessive temperatures, hot bearings, low oil
c. Motors.
Bearing troubles due to improper
pressure, diluted lubricating oil, insufficient cooling water
lubrication or excessive wear; brushholders loose,
or clogged cooling system, also abnormal loads. Any of
broken, or assembled too close to commutator; brushes
these conditions may cause serious damage to the
greatly worn, binding, or improper grade; loose
equipment.
connections, broken springs, chafed leads.
d. General. Excessive vibration causing breakage;
loose connections at terminals, fuses, etc.; blown fuses.
Section VI. HIGH POTENTIAL TESTS
periodic high potential tests on circuits and windings
62. General
carrying current of potential over 150 volts. It is
Whenever diesel-electric locomotives operate
mandatory that these tests be performed on all
under Interstate Commerce Commission regulations,
Department of the Army diesel locomotives on an
they must comply with the requirements given in
annual basis, and after general overhaul or extensive
paragraph 253 of ICC regulations for inspection and
repairs to the electrical apparatus.
testing of locomotives other than steam, governing
25
