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GN Electric Operations continued
and M-G set seems to be nearly up to full speed, you will
find voltage regulator carbon pile fuse blown. Hit stop
button, or your overspeed relay will trip. Then replace
carbon pile fuse and re-start set. You do not have to wait
for General Electric set to stop before restarting. If M-G
starts, but fails to connect to transformer, or switches 3,
8, 9 will not close, and PR3 does close, trouble will be
found on either PR3 contact, No. 10 out interlock, or No.
4 out interlock.
(g) If switches 8 and 9 fail to close when No. 3 closes,
the No. 3 in interlock will be oxidized or broken.
M-G Starts, Connects to Transformer But Will Not
Synchronize
(h) Fails to take second bump. Just as M-G reaches
full speed, relay SR (a very sensitive relay) drops out to
make contact, which closes synchronous motor field switch
No. 10. If this relay fails to close No. 10, the set runs as
an induction motor on switches 3, 8, 9 closed and start
motor switches 1 and 2 are also closed along with TDR1
and TDR2.
Note: This same effect results sometimes when
pantographs lose contact from line, tripping OL4 and JB.
circuit breakers, as well as opening No. 10.
Striking SR relay box a quick blow with hand usually
jars relay into contact, but sometimes it is necessary to hit
stop button and slow set down a bit, then push start button
and M-G set will properly synchronize if the trouble is
in SR not contacting, which is usually the case.
If M-G set starts, connects to transformer properly and
SR relay closes No. 10, but switches 4, 8, 9 fail to close,
relay TDR1 will be found stuck closed account of
mechanically stiff, or if it cannot be opened by striking bulkhead
with hand, an oxidized or broken contact on No. 10 in
interlock is cause.
Special: If M-G set starts, connects to transformer, SR
closes No. 10, switches 4, 8, 9 close and set apparently
running okay with switches 4, 8, 9, 10, 40 closed, and relays
TDR1, TDR2, SR, switches 1 and 2 open, but synchronous
ampere meter shows around 700 to 800 amperes, with
locomotive standing still and synchronous volts show around
1500 to 1600, instead of 2400 or 2500, it indicates that there
is no field current on synchronous motor, either due to a
bad contact on No. 10 switch, a broken slip ring
connection, broken resister in synchronous motor field circuit, or
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worn out slip ring brushes. Usually the cause has been
either a broken slip ring connection or bad order No. 10
switch contacts. CAUTION: Look for fireworks around
synchronous motor slip rings and call electric shop for
instructions
Engine Fails to Move
(i) M-G set running normal, switches 4, 8, 9, 10, 40 closed.
Controller off. Be sure all motor cut out switches are
closed and that roundhouse hostling switch is closed in up
position, controller fuse, 30 ampere, above engineer's head
okay, and control switch closed, JR circuit breakers both
closed. You can look at their air gaps, or try to move
their interlock carrier rods up and down. If the rods are
down, and cannot be moved, the breakers are closed. A
further check is to be sure magnet valve on JRs is not
stuck in, for if it were, the indications would be breaker
closed, while actually the contacts would be parted. Press
each magnet valve and if it exhausts when you release pin
the contacts are okay.
First notch on speed controller should close all traction
switches 11, 12, 13, 14, 15, 16, 32, 34, 38 and generator field
switch No. 45. These all stay closed until controller is shut
off. If none of the above switches close, check field
controller. It must be shut full off and not on "E" notch as
often happens. If field controller is full off, check ratchet
device. It may not be making contact. Shut off hard and
notch out again. If this fails to close ratchet device, close
it by hand. When ratchet device is closed, a quick check
is to open No. 1 compartment and watch reverse drums
with a spot light, as you throw reverse lever and notch
out on speed lever. If drums throw over, your controller,
controller switch, fuse, and ratchet device are okay. If No.
14 switch and No. 45 alone close when you notch out,
trouble is on No. 36 out interlock dirty or broken circuit.
If No. 14 alone fails to close and all others do, then No.
31 out interlock is bad order. Should switches 32, 34, 38
all fail to close while all others do, bad order interlock
will be found on Nos. 19, 21 out. When all switches close
that should, but No. 45 fails to close, either TDR2 is not
out and making good contact, or JR1, JR2 in interlocks are
dirty or bad order. If all switches close that should, as
motoring switches 11, 12, 13, 14, 15, 16, 32. 34, 38, 45, and
engine will not move, first check M-G set and be sure it is
running okay with Nos. 4, 8, 9, 10 closed. If M-G is okay
then you will find generator field fuse blown,, or a bad
Order contact on No. 45 switch, right side.
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Never take anything for granted. Always be careful
and be sure, first and last.
Engine Fails to Regenerate
M-G set running okay, engine motors okay.
(j) To regenerate properly all motor cut out switches must
be closed, JR1, JR2 relays closed and switches 1, 2, 32, 34,
38 open, along with all the mentioned interlocks making
good contact in the indicated positions. Then with field
controller on "E" notch and speed controller on any notch
from one up, the following switches will close: 14, 19, 20,
21, 28, 29, 30, 31, 33, 35, 36, 37, 39, 41, relay BR picks up.
Note: On cabs 5014 to 5017, in addition to these, switches
51, 52, 53 close.
If engine brake is set and speed lever on notch one,
when field lever is notched out beyond "E" to notch one,
then relay BR opens to make contact, and switches 11, 12,
13, 15, 16 close in addition to all those above,
Further notching on field controller operates B contactors,
while further notching on speed controller operates
M contactors.
If engine does not hold its regeneration load and all
above switches do close, then usually an arc chute on
switches 41, 51, 52, 53 is keeping switch from properly
contacting, or the regenerative field fuse is blown.
Relays
The JR circuit breakers are high speed trip devices which
protect D. C. generators from damage. They not only
open on an ordinary overload, but even beat a surge by
tripping in about, one hundredth of a second.
Symptoms
JRs trip from (1) too fast notching. (2) Grounded or
flashed over motors, or generators. (3) A. C. overload
No. 4 tripping from a surge on A. C. power, will open
No. 10, and No. 10 in interlock will open JRs, as when
pantograph bounces away from trolley wire. (4) Sand
or dirt in JR air gap will cause them to open on light
D. C. amperes. (5) Faulty adjustment (a shop job) where
calibration plug backs out too far from vibration, also
causes trouble.
Special: Generally, the JRs open on road from (1) too
fast notching, or exceeding D. C. ampere limit. (2) Ground
or flashover on generator or motor. (3) OL No. 4 tripping
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switch No. 10, dumps JRs and it SR relay does not properly
re-close No. 10, the JRs cannot be reset until M-G
switches 4, 8, 9, 10 are all closed. Sand in air gap is a
common road trouble.
The JR holding coil circuit is through D. C. traction
overloads OL1, OL2, OL3 and No. 10 in interlock. If the
JRs kick out due to a shorted traction motor, or flashed
over motor, by cutting out one group of motors at a time
with cut out switches, then trying engine, the defect can
be found. If JRs let go on first controller speed notch, you
will probably find a stuck in M contactor. Shut off and
except for M30 which is closed when M-G set is running,
all other M contactors should be open.
If any are welded shut, force them open with a stick.
By sand papering contacts, you can clear the trouble. 65
volts battery on this circuit.
Ground Relay
This relay trips if grounds occur in traction blower
motor, synchronous motor, transformer fans, heaters or
the transformer secondary.
Test to isolate trouble as follows:
(1) If synchronous motor or transformer is grounded,
there will be plenty fireworks and destruction of
equipment if power is applied. Engine is out of service when
this occurs.
(2) If ground relay trips as soon as pantograph is
raised and transformer blowers start, this indicates a
grounded transformer blower. Lower pantographs, close
ground switch, and remove both blower fuses. Examine
blower motors for burning and if one is found damaged,
leave that fuse out. By covering over the air intake of
a stopped transformer fan, one fan will get engine over
road. If no burning is apparent, then remove one fuse
and raise pantograph. If relay trips, shut down and pull
that fuse, as it is the grounded motor.
(3) A grounded cab heater will usually trip ground
relay, as well as blow the heater fuse. If inspection shows
a grounded heater, leave its switch open and pull its fuse
out. Otherwise you will have to test to see which heater
trips the relay.
BE CAREFUL AROUND ALL THESE BLOWER
AND HEATER CIRCUITS AS THEY RUN FROM
600 TO 750 VOLTS A. C.
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