| 摘要 |
In a cordless hand tool 100 having a drive motor 180 for driving a tool 120, the drive motor 180 is configured to drive the tool 120 at a preset operating speed in the load mode and in the no-load mode and a control unit 170 is provided, configured to reduce the preset operating speed in the no-load mode to a preset at-rest speed. The motor speed is increased to the operating speed from the at-rest speed if the tool 100 changes from the no-load mode to the load mode, e.g. as a portable sanding machine is applied to a workpiece. There may be a preset delay after the tool 100 enters the no-load state before the motor speed is reduced to the at-rest speed, the delay may be between 0.5 and 2.5 seconds. The motor current may be monitored to establish whether the tool 100 is operating in the no-load mode or the load mode. The at-rest speed may be less than 20% to 40% of the operating speed. The operating speed may be a working speed in the load mode or an idling speed in the no-load mode, the idling speed being higher than the at-rest speed. Reducing the no-load motor speed saves power and avoids rapidly discharging a battery pack 190. |
