| 摘要 |
PROBLEM TO BE SOLVED: To provide an electric power tool with good working efficiency in which a brushless motor can be controlled at a plurality of rotation speeds.SOLUTION: In a normal mode, duty is always maximum and the rotation speed of a circular saw blade decreases in accordance with an increase in load current from an unloaded condition. In a first economy mode, the rotation speed is controlled to be constant (constant speed control) when the load current is equal to or less than a predetermined value, which is different compared with the normal mode. But when the load current exceeds the predetermined value, the same control is performed as the normal mode. In the first economy mode, the duty becomes larger when the load becomes larger and when the load exceeds a certain value, the duty becomes maximum. When further more load is applied, the same control is performed as the normal mode even in the first economy mode. |
