2.1.2.4
Duty Cycle
Each motor, when operating at rated voltage and frequency and on the basis
of the connected pump load inertia Wk2 and the speed-torque characteristics
of the load during starting conditions as furnished by the pump
manufacturer, shall be capable of performing on a continuous basis the
following motor duty cycle without injurious temperature rise: [operation
at rated load over a period of approximately [_____] [hours] [days]] [a
running period at rated load of not less than [_____] [minutes] [hours] and
a standstill period of not less than [_____] [minutes] [hours].] A
starting information nameplate setting forth the starting capabilities
shall be provided on each motor. This nameplate shall also include the
minimum time at standstill and the minimum running time prior to an
additional start.
2.1.2.5
Balance
The balance for each motor when measured in accordance with NEMA MG 1,
paragraph 12.06 or paragraph 20.53, shall not exceed the values specified.
Each motor's characteristics shall be such that the provisions of Section
15131A VERTICAL PUMPS, AXIAL-FLOW AND MIXED-FLOW IMPELLER-TYPE paragraph
[_____] are met.
2.1.2.6
Noise
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NOTE: The Department of Defense (DOD) considers
hazardous noise exposure of personnel as equivalent
to 85 decibels or greater A-weighted sound pressure
level (dBA) for 8 hours in any one 24-hour period.
On the assumption that pumping plant operating
personnel may be exposed to noise levels approaching
or exceeding that defined by the DOD as hazardous,
the motor noise limit should be specified not to
exceed 85 dBA. The additional cost of providing
motors meeting this requirement should be
investigated and weighed against an alternate of
providing a room to isolate these personnel from the
noise exposure.
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All motors shall operate at a noise level less than 85 decibels A-weighted
mean sound pressure level (dBA). Noise shall be determined in accordance
with [_____]. The specified noise limit applies for a reference distance
of one meter for free-field conditions.
2.1.2.7
Power Factor and Efficiency
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NOTE: List power factor and efficiency for each
size. Motor efficiencies are not standardized and
vary with manufacturer. Efficiency and its
associated power factor are primarily a function of
load, horsepower rating, and speed. Some general
guidelines are as follows:
Operation below -
Decreased efficiency,
rated load
lower power factor
SECTION 16221A
Page 12
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