| 摘要 |
PURPOSE:To obtain a stable laser light of high power by controlling the rotating speed of a drive motor, thereby maintaining the gas flow rate constant. CONSTITUTION:A detecting mechanism which has a light emitting element 36 connected to a light emitting element power source 35 and a photodetecting element 37 is arranged to hold the impeller of a circulating fan 28, and the light passed through the gap between the blades of the impeller is photoelectrically converted. An electric pulse is inputted to an F/V converter which generates a voltage proportional to the frequency, a thyristor firing control circuit 32 is controlled by the output of a differential amplifier 39 which receives the output at one input land a reference voltage 40 at the other input, and a drive motor 27 is controlled through a thyristor inverter 34 by a signal from the circuit 32. When the voltage 40 is maintained constant, the driving motor 27 is rotated always at the constant rotating speed, thereby maintaining the flow rate of gas flowing through a discharging unit always constant. |
