Hitachi FS3 Series, Руководство по обслуживанию

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TROUBLESHOOTING
Additional Information for ”CHECK LIST ON COMPRESSOR”
Check Item Additional Information (Mechanism of Compressor Failure)
1 & 2 The liquid refrigerant return volume to the compressor is controlled by the discharge gas temperature Td1
when only No.1 compressor is operating. If Td1 and Td2 are reversely connected, the liquid refrigerant return
volume will become small by detecting the temperatures even if the actual discharge gas temperature is high.
Therefore, this abnormal overheating operation will result in insulation failure of the motor winding.
3, 4 & 5 Overcurrent control(operating frequency control) is performed by detecting current by the current sensor.
In this case, winding insulation failure will occur, since control is not available in spite of actually high current.
6, 7 The current sensor checks phase and adjusts output electrical wave in addition to the above mentioned items.
If fault occurs, the output electrical wave becomes unstable giving stress to the motor winding, resulting in
winding insulation failure.
8, 9 During a cooling operation, Pd is controlled by fan revolution of outdoor unit, and Td and SH are controlled by
MV of each indoor units.
During a heating operation, Td and SH are controlled by MV1 and MV2. If expansion valves are incorrectly
connected, correct control is not available, resulting in compressor seizure depending on liquid refrigerant
returning conditions or motor winding insulation failure depending on overheating conditions.
10 If the refrigeration cycle and electrical system are incorrectly connected, abnormally low suction pressure
operation is maintained or abnormally high discharge pressure operation is maintained, resulting in giving
stress to the compressor, since their correct control is not available.
11 ditto
12 The compressor may be locked due to the liquid return operation during the cooling operation.
13 In the case that the contacting resistance becomes big, voltage imbalance among each phase will cause
abnormal overcurrent.
14 In this case, overcurrent will occur, efficiency will decrease or the motor winding will be excessively heated.
15 In the case, it will result in motor burning or compressor seizure.