INVERTER OF REFRIGERATOR

摘要

PURPOSE:To eliminate the low efficiency operation of a motor by varying the output voltage for the output frequency of an inverter according to the type of the coolant in use. CONSTITUTION:A rotating speed instructing circuit 17 compares the detected temperature of a thermistor 15 for detecting the temperature in a refrigerator with the set temperature of a variable resistor 16, and outputs a rotating speed command. The command is input through a voltage/frequency converter 19 to the less significant bit of a ROM21 and through an A/D converter 22 to the more significant bit of the ROM21. The ROM21 outputs the output frequency and voltage commands of the inverter in accordance with F/f characteristic stored in advance in the A/D converter. This V/f characteristic can be replaced in response to the coolant in use. Thus, the operating efficiency of a motor can be improved.