Input Current Control - LG Multi-Inverter Type Service Manual

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+1 value, reduce inverter operation by 1 step.
- Step down 5Hz(Option) from current step.
- If new Hz is below minimum Hz 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 5 times in 1 hour,stop the operation and shows Self-Diagnosis Error Mode 22
Current(CT)
CT2
(Option)
CT1+1
(Option)
CT1
(Option)
Frequency
Setting
frequency
[Hz]
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Only for training and service purposes
5 Hz
Frequency
(Option)
fixed
Down
Frequency Setting
fixed frequency
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Part 3 Control logic
5 Hz
Frequency
(Option)
fixed
Down
LGE Internal Use Only
OFF