Provide a minimum 100 mm 4 inch alarm bell and alarm bell circuit to
actuate bell in event of machine cutout on protective devices, except when
low-pressure cutout is used as an operating control. Provide system
capacity control to adjust chiller output to a minimum of [_____] percent
of full load capacity without cycling operating compressor and to
automatically recycle system on power interruption. Provide start-up and
head pressure controls to allow for system operation at all ambient
temperatures down to [_____] degrees C degrees F.
2.1.2.9
Electric Motors and Starters
Provide induction electrical motors conforming to NEMA MG 1. Fan motor
bearings shall be permanently lubricated. Compressor starters shall be
[across-the-line magnetic] [reduced-voltage] type conforming with NEMA ICS 1
and NEMA ICS 2. Provide phase failure, over voltage and low voltage
protection.
2.1.3
Reciprocating, Helical Rotary, Scroll, Water-Cooled
**************************************************************************
NOTE: Specify applicable ratio after consulting
current literature to ensure an energy-efficient
system is provided. The ratios specified shall
permit unlimited competition among at least three
manufacturers.
**************************************************************************
ARI 550/590. Base capacity and power ratings, at the conditions indicated
and specified, on the test requirements of ARI 550/590. Power input shall
not exceed [_____] kW/kW kW/ton load at full load capacity. For
multicompressor units, not less than two independent refrigerant circuits
shall be provided. Chillers shall operate at partial-load conditions
without increased vibration over normal vibration at full-load, and shall
be capable of continuous operation down to minimum capacity.
2.1.3.1
Reciprocating Compressors
Provide with forced-feed lubrication, crankcase heater, hot-gas muffler,
and suction strainer. Cylinder unloading devices shall be unloaded when
compressor starts. Piston speed for open compressor shall not exceed
recommendations of manufacturer or 5 m/s 1000 fpm, whichever is less.
2.1.3.2
Helical Rotary Compressors
Shall be positive displacement, oil-injected type, and driven by an
electric motor. Rotors shall be solid steel, Society of Automotive
Engineers Grade 1141 or 1144. Shaft main bearings shall be either
sleeve-design type with leaded bronze or steel-backed babbit; or
frictionless bearing design, ball or roller type. Housings and covers
shall be high-grade, cast-iron or aluminum pressure castings. Lubrication
system shall lubricate rotors, bearings, shaft seal as well as rotor
sealing and cooling. Provide an oil safety cutout interlocked with the
compressor starter to allow compressor to operate only when the oil system
is operational. Provide for lubrication of bearings and shaft seals on
shutdown with or without electrical power supply.
2.1.3.3
Scroll Compressors
Three-dimensional, compliant, hermetically sealed design.
Compressors
SECTION 15601N
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