4-289
Note: Low suction state is detected by if the signal is higher than PID error level or lower than output
current.
23- 59
Source of HVAC Pressure Command *3
Range
【0】: Set by 23-47
【1】: Set by AI
*3: It is new added in inverter software V1.4.
23-59=0: Target value depends on parameter 23-47.
23-59=1: Convert the proportional target value of flow meters via AI1 input voltage value. Refer to
parameter 10-00 for the setting of AI terminal.
23- 66
Derating of Current Level (for Compressor Current) *3
Range
【10 ~ 200】%
23- 67
Derating of Delay Time *3
Range
【1.0 ~ 20.0】Sec
23- 68
Derating of Frequency Gain *3
Range
【1~100】%
23- 69
OL4 Current Level *3
Range
【10~200】%
23-70
OL4 Delay Time *3
Range
【0.0 ~ 20.0】Sec
*3: It is new added in inverter software V1.4.
The application of water-cooled chiller is when the rated current of compressor operates for 1 to 2 minutes
easily to cause damage to compressor so the inverter is required to be set two- stage protection to protect
the compressor.
Protection of first stage:
When the inverter is at constant speed and the current is higher than the derating of current level (23-66)
(this is the percentage for the rated current of compressor), it will start to count the derating of delay time
(23-67). After the counting time is over the delay one, frequency command can reach the derating of
output frequency and reduce the current load via being multiplied by the derating of frequency gain (23-68).
When the current is lower than the derating of current level, output frequency will be restored to the
frequency command. The action of derating to restore is counted one time. When it repeats more than
three times, the output frequency will stop at the last derating frequency until the current is lower than the
derating of current level (23-66).
For example: Set 23-66=80%, 23-67=10sec, 23-68=90%, the frequency command=60Hz and the rated
current of compressor=30A, then,
when the output current=27A, higher than 24A (30A*80%), 10 sec (the derating of delay time) passes, and
the output frequency=54Hz (frequency command 60Hz*90%), the output current decreases to 25A, also
higher than 24A; then another 10 sec passes, 60Hz*81%=48.6Hz, the output current decreases to 23A,
lower than 24A, so the output frequency is restored to 60Hz and the current rises to 27A. When it repeats
more than three times, the output frequency will stop at 48.6Hz and the output current decreases to 23A.
Protection of second stage:
After the current reaches OL4 current level (23-69), the inverter will count the time at the setting value of
OL4 delay time (23-70). When the counting time ends, it will decelerate to stop automatically and display
the warning signal (fault signal, OL4 Compressor Overload).
If fault occurs, PLC can read if the inverter is running from the digital output terminals. If the inverter stops,
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