Hobart 120CU20, Operation And Maintenance Manual With Illustrated Parts List

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OM-2228 / Operation and Maintenance Manual
120CU20 / Series 500120 / 400 Hz. Generator Set
October 15, 2013 Chapter 3-2
Page 6
CAUTION
Do not rotate the armature while this block is installed.
(5) Install the key in the shaft keyway.
(6) Place the bushing in the hub over the installed key, and install the coupling assembly on the
shaft, with the bushing approximately flush with the end of the shaft.
(7) Using a 3/16-inch Allen wrench, tighten the setscrew in the bushing to apply pressure on the key.
(8) Per Figure 7. Place a straightedge across the two adjacent bushings and measure the distance
from the bushings to the mounting face of the generator fan housing. Slide the coupling assembly
on the shaft until this dimension is 1/16-inch (1.6 mm)
LESS than the dimension recorded in
Figure 6 above. The tapered hub will be pulled onto the split bushing 1/16-inch (1.6 mm) when
the 3/8-16 bolts are completely tightened.
(9) Tighten the 3/8-16 bolts alternately and evenly as follows:
a Set a torque wrench to 30 foot-pounds (41 N-m) and tighten all three 3/8-16 bolts to that
value. Block the coupling against clockwise rotation with a bar, as illustrated in Figure 2.
Observe the
CAUTION above when it is necessary to rotate the shaft.
b Repeat step (a) above until 3/8-16 bolts can no longer be tightened.
c Check the dimension in Figure 7 to be sure it is the same as the dimension in Figure 6.
5) Reassemble Engine and Generator.
CAUTION
Use of the proper coupling bolts is very important. Failure to use the proper bolts, as
outlined below, can result in coupling failure and damage to the generator set.
a) Insert the new coupling bolts (see Chapter 4) with lock washers through the bushings from the FAN
side of the coupling.
b) Using a hoist, align the generator fan housing flange with the flange on the engine flywheel housing
and insert two of the attaching bolts, one on each side of the flange. Start the bolts into the tapped
holes in the flywheel housing just enough to ensure thread engagement. DO NOT TIGHTEN.
c) Block rotation of generator and turn all of the coupling bolts into the tapped holes in the flywheel until
finger tight. DO NOT tighten with a wrench.
d) Insert all remaining attaching bolts (two installed in Step B, above) through the generator flange,
engaging the tapped holes in the flywheel housing, and tighten them all securely.
e) Torque all coupling bolts to 85 ft-lbs (115 N-m).
CAUTION
Remove all armature blocks, otherwise, damage to the armature could result.