DISABLE AND LOCKOUT ANY ENGINE CRANKING
DEVICES BEFORE ATTEMPTING TO INSTALL OR
SERVICE THE GENERATOR. FOR ELECTRIC START
SETS, DISCONNECT THE CRANKING BATTERY. FOR
AIR START, DISCONNECT THE AIR SUPPLY. FOR
MOTOR GENERATOR SETS, OPEN THE POWER
SUPPLY TO THE DRIVE MOTOR. FAILURE TO
COMPLY WITH THESE SAFETY PROCEDURES
COULD RESULT IN SEVERE PERSONAL INJURY OR
EQUIPMENT DAMAGE.
NEVER "BAR OVER" THE ENGINE GENERATOR SET
USING THE GENERATOR'S FAN. THE FAN IS NOT
DESIGNED FOR THIS PURPOSE. BARRING OVER
THE SET WITH THE FAN COULD DAMAGE THE FAN
AND RESULT IN PERSONAL INJURY OR
EQUIPMENT DAMAGE.
GENERATOR MOUNTING
Single Bearing Units.
Single bearing units are provided with an SAE flywheel
housing adapter flange and flexible drive discs. Coupling the
generator's shaft to the engine flywheel is accomplished with
special steel drive discs bolted to the shaft. In addition to the
drive discs, there may be a hub spacer, spacer discs, or a
combination of hub spacer and spacer discs inserted
between the drive discs and the shaft to achieve the proper
shaft extension ("G" dimension per SAE J620c). Holes are
provided in the periphery of the coupling discs which
correspond to tapped holes in the prime mover's flywheel.
The outside diameter of the drive discs fit in a rabbet in the
flywheel so that concentricity is assured.
Grade 8 place bolts and hardened washers are recommended
to mount the drive discs to the flywheel. DO NOT USE SPLIT
TYPE LOCK WASHERS. Split lock washers when biting into
the drive disc cause stress risers which may result in the disc
fracturing.
The SAE flywheel housing adapter ring and the engine
flywheel housing are designed to match each other with no
further alignment necessary. Use grade 5 or greater
mounting bolts. MagnaPLUS
®
generator frames are
constructed with two or three bolt holes per foot. The feet
should be shimmed where necessary to obtain solid contract
with the sub-base. With the frame securely bolted to the
engine flywheel housing, there is no side thrust or pull on the
generator frame, thus no real need to secure the feet with
more than one bolt per foot.
GENERATOR MOUNTING
Two Bearing Generators -- Direct Drive
Two bearing generators are provided with a keyed shaft
extension. For direct drive generators, the assembler
furnishes a flexible coupling which is installed between the
driver and the generator's shaft. Aligning the generator and its
driver as accurately as possible will reduce vibration, increase
bearing life, and ensure minimum coupling wear. It may be
necessary to shim the generator feet for proper
support and alignment. Secure the feet of the generator with
grade 5 or greater bolts through the holes provided in the
mounting feet. Consult the coupling manufacturer's
instructions for alignment specifications and procedures.
GENERATOR MOUNTING
Two Bearing Units -- Belt Driven
Two bearing MagnaPLUS
®
generators can be belt driven
provided belts are sized and applied correctly. Please refer to
your supplier of belts and sheaves for correct sizing and
tensioning specifications. A bearing life calculation should be
performed. Marathon Electric recommends a minimum B-10
life of 40,000 hours. If cog type belts are used, a vibration may
be introduced which could lead to premature failure of the
bearings.
HYDRAULIC DRIVE WITH SHAFT SPLINE
Two Bearing Units
All 280 PDL MagnaPLUS
®
two bearing hydraulic drive
generators are equipped with a Zerk grease fitting mounted in
the drive end of the shaft. Prior to assembly to the hydraulic
drive motor, lightly coat the hydraulic drive motor shaft, and/or
grease the generator spline per the greasing instructions in
the MAINTENANCE section, page 12. DO NOT assemble
the generator to the hydraulic drive motor with the spline
dry.
END PLAY TESTING
Refer to the engine manual for recommended end play
specifications and measurement procedures. If end play is
not to specification, it is an indication that the generator shaft
is not moving freely in the assembly, and normal life of the
thrust bearing could be impaired. Probable causes of this
problem are:
1. Improper seating of drive discs in the flywheel resulting in
misalignment.
2. Improper mating of generator frame to engine flywheel
housing resulting in misalignment.
3. Improper "G" dimension per SAE J620c on either the
engine or generator.
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