MCAC-CTSM-2018-1
Flooded type water cooled screw chiller (MIC)
111
c. VFD Rating:
1) Drive shall be suitable for nameplate voltage ±10%.
2) Drive shall be suitable for continuous operation at 100% of nameplate amps and 150% of
nameplate amps for 3 seconds.
3) Drive shall comply with applicable UL, CE, and NEMA standards.
4) Drive shall be suitable for operation in ambient temperatures between 4.4 and 40 C, 95%
humidity (non-condensing) for altitudes up to 1,000 m above sea level.
d. User Interface:
Displays shall provide interface for display of VFD and chiller parameters. Viewable
parameters include:
1) Operating, configuration and fault messages
2) Frequency in Hz
3) Load side voltage and current (at the VFD)
4) kW (on the VFD interface)
e. VFD Performance:
1) VFD full load efficiency shall meet or exceed 98% at 100% VFD Rated Ampacity.
2) Displacement Input Power Factor shall meet or exceed 94% soft start, linear acceleration,
coast to stop.
3) Base motor frequency shall be either 50 or 60 Hz. Adjustable frequency range from 30 to
50 Hz or 30 to 60 Hz.
f. VFD Electrical Service (single point power):
1) VFD shall have input circuit breaker with minimum 50,000 amp interrupt capacity.
2) VFD shall have standard 1 kVA control power transformer with circuit breaker provides
power for oil heater, VFD controls and chiller controls.
3) Input power shall be 380 or 460 VAC, ±10%, 3 Phase, 50/60Hz ± 1Hz.
g. Discrete Outputs: 220-V discrete contact outputs shall be provided for:
1) Circuit breaker shunt trip
2) Chilled water pump
3) Condenser water pump
4) Alarm status.
5) Cooling tower
h. Protection (the following shall be supplied):
1) Under-voltage
2) Over voltage
3) Phase loss
4) Phase reversal
5) Ground fault
6) Phase unbalance protection
7) Programmable auto re-start after loss of power
8) Motor overload protection (NEMA Class 10)
9) Motor over temperature protection
i. VFD Testing:
VFD shall be factory mounted, wired and tested on the chiller prior to shipment.
F. Cooler and Condenser
:
1. Cooler shall be of shell and tube type construction. Units shall be fabricated with
high-performance tubing, minimum 10 mm steel shell and tube sheets with fabricated steel
waterboxes.