| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide an electric power tool which can be driven even if a commercial power source is not available or a battery voltage decreases. <P>SOLUTION: An electromagnetic wave receiving antenna 11 and an electromagnetic wave receiver 12 receive an electromagnetic wave generated from an electromagnetic wave generator 10. An electromagnetic wave converter 13 converts a received voltage to an electromagnetic wave conversion voltage. A capacitor charging part 14 charges a capacitor 15 using the electromagnetic wave conversion voltage. A power source switching controller 18 detects whether or not a voltage of a battery pack 9 is equal to or higher than a first reference value, and if it is equal to or higher than the first reference value, a power source switching part 19 switches a connection destination of a motor 2 to the battery pack 9. On the other hand, if the voltage of the battery pack 9 is lower than the first reference value (or the battery pack 9 is not mounted), the power source switching controller 18 detects a voltage of the capacitor 15, and if the voltage of the capacitor 15 is equal to or higher than a second reference value, the power source switching part 19 switches the connection destination of the motor 2 to the capacitor 15. <P>COPYRIGHT: (C)2013,JPO&INPIT |
