shown, shall be provided. For packaged equipment, the manufacturer
shall provide controllers including the required monitors and timed
restart.
b. For single-phase motors, provide high-efficiency type,
fractional-horsepower alternating-current motors, including motors that
are part of a system, in accordance with NEMA MG 11.
c. For polyphase motors, provide squirrel-cage medium induction
motors, including motors that are part of a system , and that meet the
efficiency ratings for premium efficiency motors in accordance with
NEMA MG 1.
d. Provide motors in accordance with NEMA MG 1 and of sufficient size
to drive the load at the specified capacity without exceeding the
nameplate rating of the motor. Motors shall be rated for continuos
duty with the enclosure specified. Motor duty requirements shall allow
for maximum frequency start-stop operation and minimum encountered
interval between start and stop. Motor torque shall be capable of
accelerating the connected load within 20 seconds with 80 percent of
the rated voltage maintained at motor terminals during one starting
period. Provide motor starters complete with thermal overload
protection and other necessary appurtenances. Motor bearings shall be
fitted with grease supply fittings and grease relief to outside of the
enclosure.
e. [Where two-speed or variable-speed motors are indicated,
solid-state variable-speed controllers may be provided to accomplish
the same function. Use solid-state variable-speed controllers for
motors rated 7.45 kW 10 hp or less and adjustable frequency drives for
larger motors.] [Provide variable frequency drives for motors as
specified in Section 16261 VARIABLE FREQUENCY DRIVE SYSTEMS UNDER 600
VOLTS.]
2.6
DUCT SYSTEMS
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NOTE: Identify all pressure classification for all
ductwork in accordance with SMACNA HVAC Duct Const
Stds, including points of changes in pressure
classification, on the drawings. Indicate pitch of
ductwork, low spots in ductwork, and means of
disposing of condensate, where required. Size
outdoor air intakes so that rain and snow are not
drawn into the ductwork. Slope watertight intakes
to a drain line and provide means to dispose of the
water. The requirement that outdoor air intake
ducts and plenums be fabricated watertight with
soldered or brazed joints and seams may be
eliminated where it is not anticipated that rain or
snow will be drawn into the outdoor air intake.
Limit the use of flexible duct (due to the
inordinate pressure drop and corresponding fan
energy consumption that it causes). Show the extent
of flexible duct on the drawings. Ensure that the
restrictions in these standards pertaining to the
use of non-metallic materials in air distribution
plenums are adhered to.
SECTION 15895
Page 15
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