provided to pre-vent reverse rotation of the pump. The gear reducer shall
conform to the requirements of AGMA 6010 or AGMA 6023 as applicable.
1.5.2
Design Conditions
1.5.2.1
Operating Conditions
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NOTES: The speed reducer, pump, and prime mover are
intended to be purchased together; responsibility
for establishing operating loads should be placed on
the Contractor. If the speed reducer is purchased
separately, the designer must determine the
operating loads from pump and prime mover data.
For motor stall torque, 350 percent of rated load
should be used for induction motors. For diesel
engines, the maximum torque should equal the slip
torque of the overload protection device. An air
actuated clutch should be used as overload
protection.
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The Contractor shall obtain the operating conditions from the pump and
prime mover suppliers. Operating conditions which shall be considered
include (as a minimum): maximum input power, motor or engine speed, speed
reducer ratio, maximum pump reverse overspeed, low-speed shaft downward
thrust including weight, low-speed shaft momentary upward thrust during
startup or shutdown (if applicable), high-speed shaft direction of
rotation, low-speed shaft direction of rotation, overhung load, motor stall
torque, or maximum engine overload torque transmitted through the clutch,
reverse torque load on the backstop.
1.5.2.2
Runaway
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NOTE: Delete this paragraph for engine-driven
units. If emergency closure might not be achieved
within 30 minutes, this time period must be
increased.
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The speed reducer shall be designed to withstand backstop failure and
maximum pump reverse runaway speed for a period of [30] [_____] minutes.
1.5.2.3
Critical Speeds
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NOTE: Dynamic analysis of the pump, reducer, and
engine or motor assembly will be performed by the
pump manufacturer as described in UFGS-15131A
VERTICAL PUMPS, AXIAL-FLOW AND MIXED-FLOW
IMPELLER-TYPE. If the reducer is purchased
separately from the pump, this paragraph will be
deleted and responsibility for dynamic analysis, if
done, is that of the designer.
**************************************************************************
Dynamic analysis of the pump, reducer, and motor (engine) assembly shall be
SECTION 15005A
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