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Copyright ©2008 LG Electronics. Inc. All right reserved.
Only for training and service purposes
LGE Internal Use Only
Control logic
5.1 Function
Controlling total current to protect power semiconductor devices from burn-out by the low current (including connecting
mistake) and over current.
Operating process
1. Detection : check the output DC voltage of Current Transformer(CT).
5.2 Operating process
CT 1 detection :
1) If total current exceeds CT1 value, reduce inverter operation by 1 step.
- Step down 5Hz from current step.
- If new Hz is below Minimum Hz(30Hz) of operation (cooling & heating), then turn off the compressor.
2) After step down, still if the total current exceed CT1 for more than 5 sec.
then step down inverter operation by 1 more step.
3) If the current continue below CT1 for more than 1 min., return the to setting step Hz.
CT 2 detection :
1) If total current exceeds CT2 turn off compressor.
And after 3 min turn on the compressor and check the current again.
2) If CT2 occurs 10 times in 1 hour,stop the operation and shows Self-Diagnosis Error Mode 22
5. Input Current Control
5Hz
29A
24A
26A
AHUW166A0
Cooling &
Heating
(CT 2)
Heating
(CT 1)
Frequency
Down
Cooling
(CT 1)
Model
CT2
CT1
CT1+1
Current(CT)
Frequency
[Hz]
Hz
Down
OFF
Setting
frequency
Setting
frequency
Frequency
fixed
Frequency
fixed
Frequency
fixed
Hz
Down
