WELD
W
W
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FIGURE F.21 – CHOKE TIG WELD
MAIN TRANSFORMER AND CHOKE
REMOVAL AND REPLACEMENT (continued)
REPLACEMENT PROCEDURE
1. Place the flat washers and the choke on top of the
transformer and the lift bale assembly over both.
2. Install the four thread cutting bolts that mount the
lift bale to the transformer and then replace the
choke mounting hardware that was removed in
Step 20 of the removal procedure. See
Figure F.20.
NOTE: Cover the transformer assembly with
‘damp’ shop cloths before performing Step
3 to prevent weld spatter from damaging
the transformer.
3. Thouroughly clean the choke lead and the sec-
ondary lead and TIG weld along the two edges.
The welds must be at least as long as the widths of
the two pieces See Figure F.21.
4. Mount the SCR Bridge assembly using the hard-
ware and insulators removed in Step 18 of the
removal procedure. See
Figure F.18.
5. Connect the transformer secondary and snubber
leads to the SCR assembly. See
Figure F.19
for
proper assembly. Torque all bolts per the following:
1/4” bolts
6 ft/lbs.
5/16” bolts
11 ft/lbs.
3/8” bolts
19 ft/lbs.
1/2” bolts
45 ft/lbs.
6. Using the hoist, place the transformer/lift bale
assembly over the mounting bolts in the base and
replace the hardware removed in Step 21 of the
removal procedure.
7. Carefully back track through the removal procedure,
re-routing and re-connecting the leads that were
cut, removed or separated using proper electrical
techniques and insulating where required.
8. Replace the baffles and any sleeving, cable ties or
sealants that were removed during the disassembly
procedure.
TROUBLESHOOTING AND REPAIR
F-48
F-48
DC-600
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