FLYWHEEL BALANCE WEIGHTS
TESTING AND ADJUSTING
expected total concentric runout can be held to 0.002 in
(0.05 mm).
The extended shaft rotor should be dynamically
balanced within the generator manufacturer's balance
deviation limits while suspended by the rear bearing and
extended shaft pilot diameter.
With an extended piloted rotor shaft, the coupling plates
must have clearance between the outside diameter of
the plates and the flywheel coupling plate bore.
Clearance is necessary or serious vibration may result.
The coupling plates provided with a generator which
does not have an extended shaft rotor pilot are usually of
the close fitting piloting type. These cannot be used
when the bolt-on shaft extension is used.
CATERPILLAR GENERATOR SETS
Caterpillar Generators are matched to the Caterpillar
Engine for minimum vibration. The installation group
includes proper coupling plates and, if necessary,
balance weights correctly mounted on the engine.
Current, price listed Caterpillar Generators should
always be mounted with the price listed installation
arrangement or coupling group for the engine.
TESTING GENERATOR SET ENGINES
Occasionally, a generator set engine is test run without
the generator attached. If the engine is equipped with a
balance weight on the flywheel (weight, bolt, washer or
bolt and weight), the engine will vibrate. If an engine
equipped with a flywheel balance weight is to be test run
by itself (without the generator), the test should be
performed
without
the
flywheel
balance
weight
assembly. Before the generator is mounted, be sure the
proper weight assembly (bolt and weight or bolt, weight,
and washer) is installed. Do not permit any substitution
of balance weight parts (i.e., a longer or shorter bolt).
Generator sets having piloted shaft generators may
exhibit wear on the pilot shaft, wear in the flywheel bore,
or both after extensive service. When the total
clearance between these points exceeds 0.005 in (0.127
mm), the assembly alignment function of the piloted
shaft is lost. Shaft extension diameter and flywheel pilot
bore dimensions should be checked. Bore and shaft
should be round within 0.001 in (0.025 mm). Wear
generally occurs on only a small segment of surface in
the bore and/or on the shaft diameter. During assembly,
original alignment can frequently be reestablished by
rotating the engine and generator to positions where the
flywheel bore will support the rotor shaft on previously
not worn surfaces.
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