| 摘要 |
PROBLEM TO BE SOLVED: To obtain a preventive circuit which prevents the malfunction of an apparatus and which reports an abnormality by using an alarm signal by a method wherein, when an applied-voltage supply signal and a power-supply signal are input, an applied voltage is supplied to a fan and, when an applied- voltage cutoff signal is input, the supply of an applied voltage to the fan is stopped so as to prevent a fan lock current. SOLUTION: A switch control part 3 outputs a first applied-voltage supply signal only for a prescribed time from the start of a fan 2, it outputs a second applied-voltage supply signal after a first power-supply signal is output, it outputs an alarm signal when a clock frequency is at a first frequency or lower, and it outputs an applied-voltage cutoff signal when the clock frequency is at a second frequency or lower. A switch changeover part 4 supplies a first applied voltage to the fan 2 when the first applied-voltage supply signal is input. It supplies a second applied voltage to the fan 2 when a second power- supply signal is input. It stops the supply of the applied voltage to the fan 2 when the applied-voltage cutoff signal is input. Thereby, it is possible to prevent the lock current of the fan 2. |
