LG RCWW-1 Operation & Maintenance Manual page 20

Input
Indication
M1 Contactor
M2 Contactor
M3 Contactor
Oil Flow
Oil Level
Oil Pressure Differential
Interior Protector
Phase Sequence
Overload
Cond Pressure
Evap pressure
Frosbite Preventer
Pump Contactor
Condenser Flow Switch
Emergency Protector
Remote Controller
Indication value and meaning of input display, and normal value is specified above in the table.
Especially when operating if value is inputted other than the value specified above, PLC judge the wrong
value and alarm generated which would stop the chiller.
M3 contractor of input value is electron contactor of Y short of compressor motor and it would be change
to OFF after ON about for 5 seconds in the beginning of the compressor operation. After M3 Contactor is
Off, compressor would be operated normally through that M2 Contactor , which is electron contactor for
△ short. M1 contactor would be kept ON during operation as Main contactor for power approval.
Oil Flow and Oil Pressure Differential input would be inputted for checking normal function of lubrication
with Oil Level during operation. Oil level input always keeps being on during operation and stop which is
input for getting the oil level of oil separator. Oil Flow switch monitors actual oil flow from oil separator to
compressor, Oil Pressure differential is input for checking the pressure difference between low pressure
refrigerant and high pressure of compressor which is power for making oil flow, both inputs are ON when
compressor operation is stabilized. Therefore it check if it powers on normally in 5 minutes of compres-
sor operation and it judge if it operates alarm. If it is not ON in 5 minutes of compressor operation, PLC
may recognize it alarm and stop the chiller safely.
Delay time is changeable through Parameter Setting, and contact LGE service agent when change is
needed because of alarm operation.
Chiller Water-cooled Screw
Meaning
Main electron contactor
Electron contactor for △ short
Electron contactor for Y short
Oil flow switch
Oil Level switch
Oil Pressure differential switch
Compressor interior protector
Phase sequence voltage watcher
Overload relay
Condenser high-voltage switch
Evaporator low-voltage switch
Freezing Preventer
Pump operation input interlock
Cold water/cooling water level switch
Emergency stop switch
Tele operation signal contact part
Table 2
- 20 -
Normal
condition Normal condition
when when operating
stopping
ON
OFF → ON
OFF
ON → OFF
OFF
OFF
(in 5 minutes of operation)
ON
OFF
(in 5 minutes of operation)
ON
ON
ON
ON
ON
ON
OFF
OFF
ON
ON/OFF
ON
ON
ON
ON
ON
ON
ON
ON
ON
ON
ON
ON
ON
ON/OFF