| 摘要 |
<P>PROBLEM TO BE SOLVED: To detect abnormal sparks with high reliability and with an extremely low possibility of false detection. <P>SOLUTION: The vacuum cleaner has optical detecting means 15 for detecting the quantity of carbon powder generated from the friction between a rectifier of an electric blower 2 and a carbon brush. Signal processing means 17 determines whether the state of sparks is abnormal or not based on the result of detection by the optical detecting means 15 to vary the quantity of power distribution of drive control means 19 of a bidirectional thyristor 20 to the electric blower 2 according to the output from the signal processing means 17. With this structure, abnormal sparks can be detected with high reliability and with an extremely low possibility of false detection. <P>COPYRIGHT: (C)2010,JPO&INPIT |
