INVERTER CONTROLLED AIR CONDITIONER WITH OPTIMUM DETERMINATION FOR OVER CURRENT DETECTION

摘要

A memory stores, in advance, at least a first V/F pattern corresponding to an air conditioning load and having reference voltage and frequency characteristics, and a second V/F pattern having voltage and frequency characteristics lower than those of the first V/F pattern in a starting region of a variable-capacity compressor for driving a refrigeration cycle. A detector detects an over current supplied to an inverter for driving the compressor. A controller stops the compressor through the inverter when the detector detects the over current, and restarts or holds the compressor through the inverter in accordance with the detection count of the over current. The compressor is restarted with the first V/F pattern from the memory when the detection count is smaller than a first predetermined count, and when the detection count reaches a second predetermined count larger than the first predetermined count. The compressor is restarted with reading out the second V/F pattern from the memory while the detection count is larger than the first predetermined count and is smaller than the second predetermined count. The compressor is held when the detection count reaches a third predetermined count obtained by adding "1" to the second predetermined count, thereby confirming an abnormality of and allowing determination whether the abnormality occurs in the inverter or in the compressor.