| 摘要 |
PROBLEM TO BE SOLVED: To provide both workability and safety by stopping a motor by an excessive current or reducing the number of revolution. SOLUTION: In an electric tool, when a current value of a detected motor current exceeds a second excessive current setting value, it is determined that the motor 103 is in a locked state, and a gate signal inputted by a triac 125 is stopped in an instant (S210). Further, when the current value of the motor current exceeds the first excessive current setting value, it is determined whether such a state continues for three seconds or longer (S209), and when the state continues for three seconds or longer, it is determined that there is a possibility that the motor 103 is burned, and the gate signal input by the triac 125 is stopped (S210). COPYRIGHT: (C)2010,JPO&INPIT
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