| 摘要 |
PURPOSE:To enable an element used in a power source apparatus to be of small size, by a method wherein overcurrent detection level is changed so that it rises during the voltage drop of the power source apparatus, and unnecessarily large instantaneous overcurrent capacity is removed. CONSTITUTION:After a hysteresis motor (HM) 21 is completed for starting, HM 24 is started. Since a power source apparatus 1 drops voltage then, output of a comparator 66 becomes positive logic and a switch 68 is turned on and a resistor 67 is shortcircuited thereby the setting signal VCT rises and the overcurrent decision level rises. Consequently, although overexcitation phenomenon is produced in the HM 21 and the output current of the power source apparatus 1 increases, since the overcurrent level rises, the overcurrent detection does not act. Moreover, on account of lead operation state then, the main circuit element of the power source apparatus 1 does not interrupt current actually and therefore the inconvenience due to rising of the protective level is not produced.
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