| 摘要 |
PURPOSE:To improve the controllability of the temp. in a thermostatic tank, by providing an inverter circuit for controlling the number of rotations of a freezer corresponding to the temp. change or temp. holding state in the thermostatic tank and the magnitude of a PID output signal. CONSTITUTION:The PID control signal of a temp. regulator 22 is sensed by a current transformer 24 and read in a thermostatic tank controlling microcomputer 17 through an A/D converter 21 and the thermostatic tank controlling microcomputer 17 judges whether the frequency of a compressor 8 for a freezer is increased or decreased in correspondence to the present operation mode and transmits a frequency altering order to an inverter controlling microcomputer 16. The microcomputer 16 receives said order to control an inverter 7 through a timer circuit 14, a PWM wave form synthesizing circuit 13 and a gate driving circuit 12 so as to obtain the ordered frequency.
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