Input Current Control - LG AH-W096A0 Service Manual

Control logic

5. Input Current Control

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
CT2
CT1+1
CT1
Frequency
[Hz]
Model
AHUW166A0
Copyright ©2008 LG Electronics. Inc. All right reserved.
Only for training and service purposes
Current(CT)
Hz
Down
Cooling
(CT 1)
26A
- 35 -
Heating Cooling &
Heating
(CT 1)
(CT 2)
24A 29A
OFF
Hz
Down
Frequency
Down
5Hz
LGE Internal Use Only