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GN Electric Operations continued
Trouble Shooting
The first rule is SAFETY FIRST. This means;
(1) Lower pantographs, close ground switches.
(2) Before attempting to shoot trouble, know the
sequence, or you will create trouble where none exists, by
burning up the machine circuits and liable to hurt yourself.
Never touch anything around electricity, unless you know
for sure how it works normally and how to work it
manually for test with safety to yourself and machine.
Following are sequences to be known:
General Electric dead cab sequence test. Preliminary
setup, battery switch closed, pantographs down, ground
switches closed.
(1) Place a piece of paper securely in the interlock
contact under M30 contactor. This keeps SR D. C. coil from
becoming overheated.
(2) To avoid unnecessary drain on battery, place a card
board or paper in contacts of No. 40 switch.
(3) Place paper in contact of SR relay to prevent
closing switch No. 10 until you are ready to test.
(4) Close battery switch.
For further information, or a check on this, report at
shop for demonstration test.
Normal sequence:
(A) Push in M-G start button. Immediately closes
switches 1, 2, 40, relays TDR1, TDR2 and SR pickup
(close their air gap).
If power were on, motor generator set would start and
run up to 600 R. P. M. on starting motor alone.
(B) Block closed relay PR3. Switches 3, 8, 9 close and
1, 2, 40, TDR1, TDR2, SR stay closed. Relay PR3
normally closes automatically at 600 R. P. M., as M-G takes
the first bump in connecting to transformer.
(C) Remove paper from SR contacts. Switch No. 10
closes, TDR1, 3, 8, 9 opens and switches 4, 8, 9 close, then
1, 2, TDR2 open. Normally M-G set would be synchronized
with line at full speed full volts and following switches
closed 4, 8, 9, 10, 40.
Hence, if operations (A), (B) and (C) as explained
occur in rotation shown, M-G set is okay.
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Events:
(A) Starting from rest and accelerating up to 600 R.P.M.
on starting motor alone.
(B) Connecting synchronous motor to transformer as an
induction motor.
(C) Synchronizing synchronous motor with line.
(D) Push in JR hold button and leave it in. Push in
JR reset and hold it about three seconds. This closes both
JR circuit breakers.
Straight motoring, ratio 1 to 1, field and armature
amperes alike.
(E) First notch on speed lever closes following switches
and they stay closed for motoring: 11, 12, 13, 14, 15, 16,
32, 34, 38, 45. Further notches on speed controller operate
"M" contactors, which cut out generator field resistance
a step at a time, building voltage up to full 750 D. C. on
24th notch.
Field shunting — high speed motoring.
(F) Notches beyond 24th are field shunting notches
and increase speed of motors by weakening their fields.
Switches 22, 23, 24 operate for first shunt producing a ratio
of 3 to 4 between field and armature amperes. The
second shunt notch operates switches 25, 26, 27 producing a
ratio of 1 to 2 between field and armature amperes.
(G) The last speed notch closes M-31 field contactor.
This wide open or booster notch is only used when D. C.
armature amperes do not exceed 400, otherwise generator
will be overloaded and liable to burn out.
Regeneration
(H) (a) With both control levers shut off, pull field
lever to "E" notch, then take one notch on speed lever.
Following switches should close: Nos. 14, 19, 20, 21, 28,
29, 30, 31, 33, 35, 36, 37, 39, 41, 45, 51, 52, 53 and BR relay
closes its air gap.
Note: Switches 51, 52, 53 are only on cabs 5014 to 5017.
CAUTION: Quickly check all above switches for closed,
then get off "E" notch to any other field notch or BR
pickup coil will overheat and burn up.
(b) When field lever is moved from "E" notch to first,
or No. 1 notch, switches 11, 12, 13, 15, 16 close, in addition
to those shown in (a) and engine would normally be in
regeneration.
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(c) The field lever operates various "B" contactors in
progressive notches beyond "E," and speed lever does
likewise with "M" contactors from notch 2 to 24.
The spot diagrams on control print will give all this
information in detail.
(I) Traction blower control button closes switches 42,
43, 46 unless temperature relay is tripped. If these three
switches close and blower does not start with M-G
running, it is a case of blown fuses on traction blower.
SAFETY ALWAYS. Do not touch anything and keep
out of switch chambers.
General Electric Power Sequence. Motor Generator Set
Consists of M-G set running, and a visual inspection of
switches and relays found closed. Use spotlight to look
into chambers.
Procedure:
(A) Set engine brake. Open switch chambers. In No.2
switch chamber, switches 4, 8, 9 should be found closed,
and relay TDR2 open. In No. 1 switch chamber, switches
10 and 40 should be closed and relay TDR1 open, in which
case M-G set is running okay.
Synchronizing Trouble
This shows up as (1) M-G set apparently runs okay,
but only switches 1, 2, 40 and relay TDR1 closed. This is
usually a blown fuse (10 amp.) in carbon pile relay or
voltage regulator, which prevents relay PR3 from closing.
(2) M-G apparently runs okay, but locomotive will not
move, switches 1, 2, 3, 8, 9 and relays TDR1 and TDR2
are all closed. Caused by relay SR failing to close No. 10
switch. Hitting M-G stop button, then pushing M-G start
usually cures trouble, or a light blow with fist on SR
relay box will jar contact closed. Engine cannot move
unless M-G is properly synchronized.
Motoring Circuits
(B) Close JR circuit breakers. Take one notch on speed
controller. In No. 1 chamber, switches 11, 12, 13, 14, 15, 16,
32, 34, 38 close. In No. 2 chamber, 45 closes, indicating
engine motors okay.
(C) Shut off speed lever and take "E" notch on field
lever, then one notch on speed lever. In No. 1 chamber,
switches 19, 20, 21, 28, 29, 30, 31, 33, 35, 36, 37, 39, 45 and
14, 41 close; also on cabs 5014 to 5017, switches 51, 52, 53
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close. This indicates engine will readily equalize okay for
getting into regeneration.
(D) Move field lever beyond "E" notch to No. 1 notch
and braking relay BR drops out, closing switches 11, 12,
13, 15, 16. Regeneration setup completed, now switches 11,
12, 13, 14, 15, 16, 19, 20, 21, 28, 29, 30, 31, 33, 35, 36, 37.
39, 41, 45, (51, 52, 53 on cabs 5014 to 5017) indicating
engine regeneration okay.
This data shows what actually happens when terminal
tests are made prior to taking engine on train. The
engines' meters indicate as covered by "Terminal test data."
Westinghouse Dead Cab Sequence — Motor Generator Set
SAFETY FIRST. Have pantographs down and ground
switches closed. Be sure switch control boards on all cabs
of combination have all switches open. Then proceed on
cab under test as follows: (1) Block closed the line relay.
(2) Run one long jumper from flexible shunt of A4
contactor to right hand blade of the Open Control switch. (3)
Run one short jumper from the stationary jaw of the open
battery cut out switch, to the left hand blade of the open
control switch. (4) Close only the M-G stop switch and
be sure all other switches on board are open.
M-G Sequence Starting
(a) Notch out on start controller, first notch; closes all
but one of "G" contactors, and switches ST1 and ST2.
(b) Second notch; in addition to above, closes ST4.
(c) Third notch; closes ST3 and opens ST4.
(d) Fourth notch; ST1, ST2, ST3, ST4 and all "G"
contactors but G-3 are closed. If machine does not start
turning now, it will not start under actual conditions. Shut off
and try again, as too quick notching skips over first notch
too fast and ST1 and ST2 fail to close.
(e) Further notching beyond fourth merely weakens
field of generator, and would speed it up as a motor if
power were applied, by dropping out various "G" contactors.
(f) Normally, at 250 R. P. M., relay SR1 would close.
Close it by hand and block it in. Switches ML and SL will
be found closed and all of the "G" contactors and ST
switches will be opened, which is okay and indicates
sequence correct to here. '
Note: Actual failure of a coil or resister tube SR1 relay
would prevent relay closing in service, and M-G set would
not change over from battery driving generator to
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