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GN Electric Operations continued
Normally the compressor will start and pump main
reservoir up to around 130 lbs., and switch control air up to
70 lbs. After compressor cuts out, then M-G set may be
started, and the other compressor cut in.
Westinghouse compressor troubles:
(1) Compressor pumps up to about 90 lbs., and cuts out,
because the compressor snap switch is not closed. Close
proper snap switch.
(2) Compressors pump up beyond 130 lbs., and pops
start letting go around 150 to 160 lbs. Cause: more than
one compressor snap switch closed. Be sure only one snap
switch and one governor cut out cock are cut in, and both
of these on the same cab. All other snap switches open,
and all other governor cut out cocks cut out.
(3) Compressor will not start. Check battery voltage on
bus line voltmeter on starting panel. If this voltage shows
around 100 battery main fuse is okay. The control fuses
under main control switch are okay. if S. E. contactor is
heard opening and closing as control switch is pulled out
and re-closed.
(4) Compressor may fail to start due to a blown compressor
fuse, or a defective burned contact on compressor
air switch. If fuses on compressor are blown, replace them.
If air switch contacts are burned off, or air switch
operation defective, cut out the compressor knife switch until
repairs made.
Compressor governor failure on Westinghouse cab's
would allow compressor to keep running until it was cut
out by compressor knife switch, as: the Westinghouse
compressor switch is normally spring closed and air opened
by means of an inverted action magnet valve which
when de-energized by governor contacts lifting, causes air
to enter inverted action compressor switch (spring closed),
pumping switch open, and stopping pumps at proper setting.
Always have two compressors cut in on a two or three
cab engine. In case of governor failure on any cab, cut bad
order governor out, turn snap switch off, and then cut in
any other cab governor and snap switch to control pumps.
Electric Locomotive Blowers or Cooling Fans
Westinghouse blowers: The M-G set is cooled by its own
built in turbine fan, while the transformer and traction
motors are cooled by three individual motor driven fans or
blowers.
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Blower No. 1 cools No. 1 and No. 2 traction motors.
Blower No. 2 cools No. 3 and No. 4 traction motors, while
the third blower cools transformer. These three motors
are all of the 10 H .F. standard squirrel cage, three phase,
induction type, operated at 625 volts A. C., and drawing
their three phase power from a "Scott" connection. One
leg of this connection comes from a separate winding on
synchronous motor, while the other from suitable
transformer taps.
Special note: These three phase motors are three phase
starting, after M-G set is running, but they run single
phase as soon as controller is notched out to run
locomotive. Also the blowers will run single phase okay. if M-G
set is shut down unless circuit breaker is opened, as in
winter where an order to shut down M-G set is received,
but cab heat is needed by crew. Then by simply pulling
M-G stop switch, the M-G will shut down, and blowers
will keep running. DANGER! The transformer must
never be left energized unless transformer blower is
running, and Westinghouse blowers cannot be started without
first starting M-G set.
Blower control: All three blower motors are controlled
from the blower control switch. If any individual blower
stops, then it is because the fuses of that one blower motor
are burned out.
Cabs 5004 and 5006 have a total of six blower fuses, or
two fuses per motor. Any one fuse blown will stop a motor.
Cabs 5000, 5001, 5002, 5003, 5008-A and 5008-B have a
total of nine blower fuses per cab, or three fuses per blower
motor. In cases of blown fuses remove and test all fuses
to save time. Be sure circuit breaker open before touching
any blower fuses.
SAFETY ALWAYS. NEVER WORK HOT CIRCUITS. BURNING OFF FINGERS, OR
ELECTROCUTION IS PRICE OF CARELESSNESS.
Failure of blowers to start:
(A) Ordinarily one blower failing to start and run
simply means that one or more of its fuses are blown.
(B) If all blower motors fail to start when blower
switch is operated, the trouble can be in any one of the
following places, provided the M-G. set is running normally.
(1) In the blower relay contacts (called no voltage relay
on print, and line relay on old motors) not making, or
oxidized.
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(2) RL in interlock not making or oxidized.
(3) Blower control switch drum or fingers either,
oxidized or not making contact.
(4) Safety interlock on door over blower contactors not
making or oxidized.
(5) Failure of one of blower contactors to close, as A1,
A2, A3 must all close to start blowers.
(6) All blowers with one or more blown fuses in their
circuit, a possible, but not probable condition.
(7) Door left off over blower contactors, causing safety
interlock to be open.
(8) Control trouble will prevent switches A1, A2, A3
closing. Power circuit trouble will be found usually as
blown fuses and oxidized blower switch contacts A1, A2
and A3.
Failure of blowers while running: The blowers may start
okay but quit while engine is running, due to:
(1) Blower relay contacts breaking or oxidized.
(2) Fuses blowing.
(3) If blowers run okay while controller is shut off,
but quit when controller is notched out, then trouble will
be a dirty or broken disc on A1 in interlock.
Note: All blowers on Westinghouse cabs must run all
the while cab is working, and the transformer blower must
run all the while transformer is energized, or transformer
burnout and fire will result. Firemen must watch these
blowers.
SAFETY ALWAYS. Shut down engine, lower pantographs,
close ground switches to work on locomotive circuits.
REMEMBER, your first mistake is your last one
around high voltage circuits.
General Electric And Westinghouse Locomotives
Winter ventilation: Due to excessive temperature variations
in winter, it was found necessary to control the
temperature of apparatus and cabs through eight mile tunnel.
Normally all our electric locomotives draw air from
outside into cab through louvers or vents in the sides of
cab. The fans or blowers then pass this cold air through
the machines being cooled, and exhaust from machines
through other roof vents, to atmosphere. Winter ventilation
simply diverts this exhaust air from M-G sets and
transformer, back into cab interior, where it is re-circulated
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into machines, instead of direct to atmosphere. In
this way the internal temperature of cab is raised by the
warm exhaust air, and the M-G set and transformer
temperatures are raised by the re-circulation of this warmed
air. This brings machine temperatures nearer or slightly
above tunnel temperature, and prevents formation of frost
and excessive condensation due to temperature difference,
and minimizes danger of high voltage creepage and flash-
over in machines, especially transformers. This re-circulation
of air also reduces the amount of outside air taken
into cab, hence reduces the amount of rain, snow and moisture
that would ordinarily enter machinery compartments.
SAFETY FIRST: If ventilation dampers are not properly
set, there is danger of closing dampers so that air is
blocked inside machine and cannot get out either to cab
interior, or atmosphere, in which case synchronous motor,
D. C. generator and transformer are liable to catch fire
and burn up. Engine and shop crews make sure that air
dampers are set according to instructions.
General Electric cabs are normally equipped with
exhaust damper vents on both sides of main generator opening
into aisles. Synchronous motor damper vents are located
up above No. 3 and No. 4 M-G bearings. For normal operation,
all four of these vents are kept closed, and
the cooling air is exhausted through roof vents to
atmosphere. In cold stormy weather, the synchronous motor
vents up over No. 3 and No. 4 M-G bearings are all opened
to exhaust inside cab. The main generator damper vents
on aisles are opened so as to exhaust into cab aisles, and
the cab louvers or side vents of cabs are closed. This
combination will take care of engine in ordinary cold stormy
weather. In addition, one transformer fan is cut out.
For zero and sub-zero weather, the shop applies roof
hoods, which seal all roof atmospheric exhausts and all of
the M-G set ventilation air exhausts inside of cab and is
re-circulated.
CAUTION: Engineers, firemen and shopmen be sure
that exhaust air from machines is coming out in aisle
exhausts through dampers or doors up over both synchronous
motor bearings and from side of main generator, for
if these doors are closed when roof hoods are on, then the
air is trapped in machine and fire will result.
If cab or M-G bearing temperature seems too high, firemen will
open windows in both aisles. The draft will cool
machine. That ventilation must not be trapped under any
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