Figure 2 - Chiller Control System - Quantech QTC4 STYLE A Series Installation Operation & Maintenance

SECTION 2 - PRODUCT DESCRIPTION
INPUTS
Pressure Transducers
Temperature Sensors
Switches
Liquid Flow
High Pressure
Start/Stop
Level
Customer Supplied
Contacts
COMMUNICATIONS
Building Automation
Printer Modem
3 Phase Power Line
Rectifier
Signal From Main Control Panel

FIGURE 2 - CHILLER CONTROL SYSTEM

Oil separators utilize no moving parts. Oil cooling is
accomplished by refrigerant leaving the eductor flash-
ing in the suction line which cools the oil, motor and
compressor.
An integral liquid cooled, transistorized, PWM,
Variable Speed Drive (VSD) is controlled by the chiller
microprocessor control panel to start/stop, select com-
pressors to run, and select compressor speed. Displace-
ment Power Factor is 0. 95 at part or full load.
16
CONTROL
Chiller Control
Microprocessor
User Interface
Display and
DISPLAY KEYPAD
AC/DC Rectifier
Rectifier Controller
SCR Trigger Board
VSD Logic Board
PANEL
Board)
Keypad
Power Driver
(IGBT)
IGBT Gate Driver
PWM Signal
The chiller microprocessor communicates with the
VSD Logic Board via a 3-wire RS-485 opto coupled
data link. The VSD Logic Board runs the number of
compressors required to meet the load and the com-
pressors to the speed requested by the chiller micro-
processor.
The basic system control and VSD system architecture
is shown in Figure 2 on Page 16.
FORM QTC4-NM1
ISSUE DATE: 4/2/2018
OUTPUTS
Relay Output Board)
Solenoids
Contactors
Alarm
Pump
Compressor Heater
Run Status
Evaporator Heater
VSD
VSD Logic Board
SCR Trigger Board
Power Components
PWM (Speed Control)
MOTOR
Compressor 1
Compressor 2
Inverter
LD15158
QUANTECH
LD15028