| 摘要 |
PURPOSE:To facilitate restarting of an electric motor, by a method wherein a breaker, stopping an electric motor, and a throttle valve, throttling an airflow in a piping, are located in a piping through which an unloader pilot valve, to which an air tank is attached, and the unloader cylinder of a compressor are interconnected. CONSTITUTION:During normal operation in which a pressure in an air tank 3 is lower than a given value, a compressor 2 is actuated with the aid of an electric motor M, and a pressurized air is stored in the air tank 3 through a suction port 31, a suction valve 12, a discharge valve 13, a discharge port 32, a piping 37. Meanwhile, when the pressure in the air tank 3 exceeds a given value, an unloader pilot valve 4 is opened, a high pressure air is fed to a piping 7 to stop the electric motor M with the aid of a breaker 9, and a rod 34 of an unloader cylinder 5 is depressed by means of a throttle valve 10 to open the suction valve 12. This enables the electric motor M to function the compressor 2 under a racing state or a so-called no-load state. This enables smooth starting of the electric motor M even when a voltage is dropped. |
