Specifications

Catalog WSC/WDC-4 93
2. A digital regulator shall provide V/Hz control.
3. The VFD shall have 110% continuous overload of continuous amp rating with no
time limit, PWM (pulse width modulated) output, IGBT (insulated gate bipolar
transistors) power technology, full power rating at 2kHz, DC bus inductor
(choke), and wireless construction.
4. Units 273 amps and below shall be air-cooled, units above 274 amps shall be
water-cooled. All heat producing devices shall be contained in a single heatsink
with single inlet and out connections for the connection of chilled water. When
factory mounted on the chiller package, the water connections shall be piped and
leak tested at the factory.
Medium Voltage (601 through 5000 volts) and High Voltage (5001 through 7200 volts).
The starter shall be:
Solid-State Reduced Voltage - Starter shall be furnished with silicon controlled
rectifiers (SCR) connected for starting and include a bypass contactor. When
operating speed is reached, the bypass contactor shall be energized removing the
SCRs from the circuit during normal running.
1. The starter shall be coordinated with the chiller package(s) making certain
all terminals are properly marked according to the chiller manufacturer’s
wiring diagrams.
2. The starters shall be equipped with redundant motor control relays (MCR)
with coils in parallel. The relays interconnect the starters with the unit
control panels and directly operate the main motor contactors. The MCRs
shall constitute the only means of energizing the motor contacts.
3. The main contactors shall have a normally open and a normally closed
auxiliary contact rated at 125VA pilot duty at 115 VAC. An additional set
of normally open contacts shall be provided for each MCR.
4. There shall be electronic overloads in each phase set at 107% of the rated
load amps of each motor. Overloads shall be manual reset and shall de-
energize the main contactors when the overcurrent occurs. The overloads
shall be adjustable and selected for mid-range. Overloads shall be adjusted
for a locked rotor trip time of 8 seconds at full voltage and must trip in 60
seconds or less at reduced voltage (33% of delta LRA).
5. Each starter shall have a current transformer and adjustable voltage
dropping resistor(s) to supply a 5.0 VAC signal at full load to the unit
control panels.
6. Each starter shall be equipped with a line-to-115 VAC control transformer,
fused in both the primary and secondary, to supply power to the control
panels, oil heaters and oil pumps.
7. Each starter shall include the following:
8. Phase failure and reversal protection
9. Load break disconnect switch
10. Current limiting power fuses
--OR--
Across-the-Line type with primary contactor allowing locked rotor amps to reach the motor
when energized.
--OR--
Autotransformer type factory wired to the 65% tap with drawout magnetic, three-pole,
vacuum break shorting contactor, drawout magnetic, two-pole, vacuum break starting
contactor, and open delta starting auto-transformer factory set at 65%.
--OR--
Primary Reactor type with drawout magnetic, three-pole, vacuum break shorting assembly,
and three-phase starting reactor, factory set at the 65% tap.
All medium and high voltage starters shall have the following components:
Main Control Relays