performed by the pump manufacturer. The reducer manufacturer shall
coordinate with the pump manufacturer in performing the dynamic analysis.
The reducer manufacturer shall make any design modifications to the reducer
which are necessary to avoid resonances in the system. A torsional or
lateral natural frequency within 25 percent of normal operating speed of
any shaft or gear mesh frequency is unacceptable.
1.5.3
Arrangement
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NOTE: In making choices as to the reducer
arrangement, the designer must coordinate with the
pump (UFGS-15131A) and prime mover specifications.
These contain statements on shaft configuration.
The hollow output shaft arrangement is preferred for
ease of installation. If the reducer is purchased
separately from the pump and prime mover, the
designer is responsible for determining input and
output shaft details and ensuring the reducer will
be compatible. For reducers driven by a diesel
engine, an air actuated clutch is recommended. The
clutch should be part of the diesel engine
specification.
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[The arrangement shall use a true hollow low-speed shaft where the pump
shaft passes concentrically through the reducer shaft allowing finite
impeller elevation adjustment.] [The speed reducer output shaft shall be
connected to the pump using a rigid coupling.] [The speed reducer input
shaft shall be connected to the motor shaft by a flexible coupling.] [The
speed reducer input shaft shall be connected to the engine with two
universal joints and an intermediate shaft.] [The speed reducer input
shaft shall be connected to the engine with a flexible coupling.] The
Contractor shall ensure compatibility and fit of the reducer high- and
low-speed shafts with that of the pump and prime mover. The speed reducer
mounting shall be designed to permit removal of the reducer and
reinstallation without requiring realignment of the reducer and shafting.
Before assembly, each gear and shaft assembly shall be dynamically balanced.
PART 2
PRODUCTS
2.1
GENERAL
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NOTE: Application factors of 1.25 (electric motor)
and 1.50 (diesel engine) are the values recommended
by EM 1110-2-3105 MECHANICAL AND ELECTRICAL DESIGN
OF PUMPING STATIONS. These are suitable for most
applications. Where reducer operating conditions
are considered severe, the application factors of
1.75 (electric motor) and 2.0 (diesel engine) may be
used to increase reliability.
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The reducer assembly shall be rated in accordance with AGMA 6010 or AGMA
6023 as applicable. The unit rating shall be equal to or exceed the
maximum input power times an application factor. The application factor
shall be [1.25] [1.75] for reducers driven by electric motors and [1.5]
[2.0] for reducers driven by diesel engines.
SECTION 15005A
Page 10
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