Polyphase motors larger that 125 horsepower shall be tested in accordance
with IEEE Std 112 with stray load loss determined by direct measurement or
indirect measurement (test loss minus conventional loss).
The efficiency shall be identified on the motor nameplate by the caption
NEMA Nominal efficiency or NEMA Nom eff.
2.3.8.1
Main Electric Drive Motor
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NOTE: Centrifugal compressors are normally provided
with 3600 rpm induction motors. The specification
will be considered restrictive by manufacturers if
an 1800 rpm synchronous motor is specified because a
special speed increasing gearbox will make them
noncompetitive with nonlubricated rotary compressors.
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The main drive motor for each compressor shall be an induction motor,
[_____] kW horsepower, with a continuous service factor of 1.0. Size the
motor so that the nameplate kW horsepower rating is not exceeded under the
entire range of operating conditions specified. Motor shall be high
efficiency type, rated not less than 95 percent based on IEEE Std 112
testing and labeling. Electrical service will be as specified. Motor
shall be designed for reduced voltage starting [at [50] [65] [80] percent
of full voltage], allowing for characteristics of the connected load, and
shall start without undervoltage tripping. Provide resistance temperature
detectors (RTD) attached to or imbedded in motor winding for control
system. The motor shall meet the requirements of NEMA MG 1 with Class F
insulation. Motor design shall include acoustical covering and reduced
noise air intake housing and be rated for 84 dBA or less at 0.9 m 3 feet
under full load. Provide space heaters for protection of windings during
motor shutdowns.
2.3.8.2
Accessory and Related Equipment Motors
Motors less than 3/8 kW 1/2 horsepower shall be single-phase induction
motors and shall conform to NEMA MG 1. Motors 3/8 through 3.75 kW 1/2
through 5 horsepower shall be three-phase induction motors and shall
conform to NEMA MG 1. Single-phase and three-phase motors shall have
bimetallic disk thermostats attached to or imbedded in the motor winding.
Motors shall have NEMA MG 1 Class B insulation.
2.3.9
Control Panel
Control unit panel conforming to NEMA ICS 6, package or frame mounted,
factory designed, assembled, and mounted shall be provided complete with
connections made to sensing points. The panel shall be fabricated of
formed stretcher leveled sheet steel, reinforced, and assembled into a
rigid unit. Gasketed access doors shall be provided as required. Panel
shall be factory finish painted. The panel shall meet NEMA 12 requirements.
a.
Panel shall contain electric and safety control work required,
including either alarm annunciator or individual labeled pilot
lights arranged in a group. Panel shall contain alarm device with
light and silencing. Generalized arrangement in accordance with
drawings.
b.
Panel shall contain start and stop buttons (the latter with
SECTION 15213N
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