| 摘要 |
PROBLEM TO BE SOLVED: To improve reliability of a compressor by not conforming the rotational speed of a DC motor to the rotational speed at which the compressor resonates. SOLUTION: A rotational speed calculating means 109 calculates rotational speed. A rotational speed control means 108 controls to set the rotational speed of the DC motor 104 to a command rotational speed by comparing the rotational speed of the command rotational speed with the calculated rotational speed of the DC motor 104. When voltage applied to the DC motor 104 reaches the upper limit, the rotational speed control means selects rotational speed lower than the command rotational speed from a set rotational speed stored in a set rotational speed storage means 115 and controls to set the rotational speed of the DC motor to the selected rotational speed. When motor current is reduced, the motor is operated at the command rotational speed. Accordingly, the compressor 114 is not rotated at the resonance rotational speed, and reduction in cooling capability is minimized. COPYRIGHT: (C)2009,JPO&INPIT
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