| 摘要 |
PROBLEM TO BE SOLVED: To prevent heating effects and attain precise speed control by reverse switching the electric motor speed for output control with the pulse inputs which moves vertically, in response to a threshold specifying a dead band. SOLUTION: The mechanical inputting device 1 of a variable register controlled at a mechanical position, in response to the direction changing signals for normal or reverse rotation operates to actuate a chopping wave generating circuit 2, which is connected to an electric motor 5 via a dead band setting circuit 3 and a motor drive circuit 4 connected with a temperature decreasing voltage detection circuit 7, which processes signals from a temperature sensor 6. The upper half and the lower half with respect to the center of the preset dead band width are subjected to normal and reverse rotation PWM wave respectively. It moves arbitrarily, straddling the upper and lower threshold in response to the drive signals. When the chopping wave is within the dead band width, the PWM wave is not outputted, and the electric moor is in a stopping condition. If it exceeds the upper threshold, the electric motor rotates normally. If it is positioned above the threshold, the PWM wave rotates normally at full speed with 100% duty ratio. |
