POWER AND ELECTRICAL
•Johnson Controls has over 25 years of experience designing variable speed drives specifically for chiller applications. The result is an extremely reliable air cooled chiller system that offers industry leading ef- ficiency at real world operating conditions, valve-less compressor loading/unloading, excellent capacity control, high power factor and soft start.
•All controls and motor starting equipment necessary for unit operation shall be factory wired and function tested.
•VSD Power/Control Panel includes main power connection(s), VSD and fan motor contactors, cur- rent overloads, and factory wiring. Standard design includes NEMA 3R (IP55) rating, powder painted steel cabinet with hinged, latched, and gasket sealed outer doors equipped with wind struts for safer servicing.
•VSD section of power panel includes a dedicated inverter for each compressor.
•The panel includes control display access door so display and control features can be accessed without opening main cabinet doors.
•Two and three compressor models come standard with single point power connection. In addition, all models are supplied with a factory mounted and wired control transformer that will supply all unit control voltage from the main unit power supply. The transformer utilizes scheduled line voltage on the primary side and pro- vides 115V/1Ø on secondary.
•The standard power panel is equipped with terminal block electrical connections at the point of incoming power. An optional factory mounted circuit breaker is available, at point of incoming single point connection, that provides the means to disconnect power and short circuit protection. The optional lockable operating handle extends through the power panel door so that power may be disconnected without opening any panel doors.
•Short Circuit Withstand Rating of the chiller electri- cal enclosure is 30,000 Amps for standard terminal block connection. Ratings IAW (in accordance with)
UL508. (See Accessories and Options section: Can be increased to 65,000 Amps for 380, 400 & 460V).
•Compressor motors are powered by a variable speed drive. Therefore, motor current never exceeds the rated load amps (RLA), providing soft starts with no electrical inrush. This eliminates the motor heating and stress always found with conventional motor starters. In addition, by eliminating the heat build up during starting, the required off-time between starts is reduced to a maximum of two minutes.
•Many utility companies charge an additional fee
if power factor is below 0.95. These power factor adjustments/penalties can affect both regular tariff rates, as well as demand charges. All YCIV models have a full load power factor of 95% and maintain this level throughout the operating range. Specifications should always require the installing contractor to be responsible for additional cost to furnish and install power factor correction capacitors if they are not fac- tory mounted and wired.
S E M I - H E R M E T I C Y O R K T W I N S C R E W COMPRESSORS
Johnson Controls Engineered Systems’ Chiller Design Team has developed a world class compressor with un- equaled performance:
•Continuous function, microprocessor controlled, VSD provides valveless, smooth capacity control from 100% down to 10% of chiller capacity for two compressor chillers and 100% down to 7.5% for three compressor chillers. In addition, elimination of the slide valve and associated unloading components resulted in a 50% reduction in compressor moving parts.
•Compressors are direct drive, semihermetic, rotary twin-screw type, including: muffler, temperature ac- tuated ‘off-cycle’ heater, rain-tight (IP55) terminal box, discharge shut-off service valve, and precision machined cast iron housing mounted on neoprene isolators.
•Reliable suction gas cooled, high efficiency, acces- sible hermetic compressor motor, full suction gas flow through 0.006” maximum mesh screen, with inherent internal thermal overload protection and external cur- rent overload on all three phases.
•Suction gas screen and serviceable, 0.5 micron full flow oil filter within the compressor housing.
•Cast iron compressor housing precisely machined for optimal clearances and superb efficiency. Entire compressor, from suction to discharge has a Design Working Pressure of 350 PSIG (24 bar) or higher.
REFRIGERANT CIRCUIT
•Independent refrigerant circuits per compressor, each using copper refrigerant pipe formed on computer controlled bending machines. This eliminates over
60% of system piping brazed joints as compared to designs that use fittings, resulting in a highly reliable and leak resistant system.
•Liquid line components include: liquid line shut-off valve with charging port, low side pressure relief de- vice, high adsorption removable core filter-drier, sight glass with moisture-indicator, and electronic expansion valve.
JOHNSON CONTROLS
