| 摘要 |
PURPOSE:To stably control a system, by comparing the output of pulsation frequency, which is included in discharge pressure, with a set value, which is regulated depending on heat load, to control the speed of an AC motor. CONSTITUTION:A pulsation frequency detector 4 is connected to the discharge pipe of a screw compressor 1. The output of the detector 4 is applied to a frequency controller 7 through a regulator 5. A suction pressure detector 10 is connected to the suction pipe of the screw compressor 1. The output of the detector 10 is applied to a frequency setting unit 8 through the regulator 5. The output of the unit 8 is applied to the frequency controller 7. The controller 7 compares the output of pulsation frequency with a set value controlled depending on heat load, to control the speed of an AC motor 2. According to this constitution, the time constant of a circuit is made small. For that reason, stable control with less time lag is enabled. |
