Carrier 23XRV manual Guide specifications cont

Guide specifications (cont)

equipment to dissipate the motor heat as per the following formula:

Btuh = (FLkW motor) (0.05) (3413) Btuh = (FLkW motor) (171)

and, alternately Tons = Btuh/12,000

The additional piping, valves, air-handling equipment, insulation, wiring, switchgear changes, ductwork, and coordination with other trades shall be the responsibility of the mechan- ical contractor. Shop drawings reflecting any changes to the design shall be included in the submittal, and incorporated into the final as- built drawings for the project.

8.Also, if an open motor is provided, a mechani- cal room thermostat shall be provided and set at 104 F (40 C). If this temperature is exceeded, the chillers shall shut down and an alarm signal shall be generated to the central Energy Management System (EMS) display module, prompting the service personnel to diagnose and repair the cause of the overtem- perature condition. The mechanical contractor shall be responsible for all changes to the design, including coordination with temperature control, electrical and other trades. In addition, the electrical power consumption of any auxil- iary ventilation and/or mechanical cooling required to maintain the mechanical room con- ditions stated above shall be considered in the determination of conformance to the scheduled chiller energy efficiency requirement.

D.Unit-Mounted Variable Frequency Drive (VFD) with Built-In Harmonic LiquiFlo™ II Filter:

The compressor shall be factory-mounted, factory- wired and factory-tested prior to shipment by the chiller manufacturer. All interconnecting wiring and piping between the VFD and the chiller shall be factory-installed. Customer electrical connection for compressor motor power shall be limited to main power leads to the VFD, and wiring liquid pumps and tower fans to the chiller control circuit. The VFD shall incorporate the following features:

1.Design:

a.The VFD shall be refrigerant cooled, microprocessor based, pulse width modu- lated design. Water cooled designs are not acceptable.

b.Input and output power devices shall be Insulated Gate Bipolar Transistors (IGBTs).

c.Rectifier shall convert incoming fixed volt- age/frequency to fixed DC voltage.

d.Transistorized inverter and control regulator shall convert fixed DC voltage to a sinusoidal PWM waveform.

e.Low voltage control sections and main power sections shall be physically isolated.

f. Integrated controls shall coordinate motor speed to optimize chiller performance over a wide variety of operating conditions.

2.Enclosure:

a.Pre-painted unit mounted, NEMA 1 cabinet shall include hinged, lockable doors and removable lifting lugs.

b.The VFD shall have a short circuit interrupt and withstand rating of at least 65,000 amps.

c.Provisions to padlock main disconnect han- dle in the “Off” positions shall be provided. Mechanical interlock to prevent opening cabinet door with disconnect in the “On” position or moving disconnect to the “On” position while the door is open shall be provided.

d.Provisions shall be made for top entry of incoming line power cables.

3.Heat Sink:

a.The heat sink shall be refrigerant cooled. Heat sink and mating flanges shall be suit- able for ASME design working pressure of 185 psig (1276 kPa).

b.Refrigerant cooling shall be metered to maintain heat sink temperature within acceptable limits for ambient temperature.

4.VFD Rating:

a.Drive shall be suitable for operation at name- plate voltage ±10%.

b.Drive shall be suitable for continuous opera- tion at 100% of nameplate amps and 150% of nameplate amps for 5 seconds.

c.Drive shall comply with applicable ANSI, NEMA, UL and NEC standards.

d.Drive shall be suitable for operation in ambient temperatures between 40 and 122 F (4 and 50 C), 95% humidity (non-condensing) for altitudes up to 6000 ft (1829 m) above sea level. Specific drive performance at jobsite ambient temperature and elevation shall be provided by the manufacturer in the bid.

5.User Interface:

A single display shall provide interface for pro- gramming and display of VFD and chiller parameters. Viewable parameters include:

a.Operating, configuration and fault messages

b.Frequency in hertz

c.Load and line side voltage and current (at the VFD)

d.kW

e.IGBT temperature

6.VFD Performance:

a.The VFD Voltage Total Harmonic Distortion (THD) and Harmonic Current Total Demand Distortion (TDD) shall not exceed IEEE-519 requirements using the VFD circuit breaker

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