Air compressor

An air compressor comprising:

• a motor;
• an inverter that controls a speed of rotation of the motor;
• a compressor main body that is driven by the motor to compress air;
• a delivery pressure sensor that senses a delivery pressure of the compressor main body;
• and
• a controller configured to perform operation control that varies the speed of rotation of the motor via the inverter such that the delivery pressure sensed by the delivery pressure sensor becomes a control pressure as a set pressure,
• wherein the air compressor includes a device that senses or inputs an atmospheric pressure,
• wherein the controller corrects the control pressure such that a ratio between the atmospheric pressure sensed or input by the device and the control pressure becomes a set value set in advance,
• wherein the air compressor further comprises at least one of a suction of a suction throttle valve capable of closing a suction side of the compressor main body and an air discharge valve capable of discharging air on a delivery side of the compressor main body, and
• wherein the controller is configured to:
• perform the operation control that switches from load operation to no-load operation by controlling at least one of the at least one of the suction throttle valve and the air discharge valve when the delivery pressure sensed by the delivery pressure sensor is equal to or higher than an upper limit pressure, and that switches from the no-load operation to the load operation by controlling at least one of the at least one of the suction throttle valve and the air discharge valve when the delivery pressure sensed by the delivery pressure sensor is equal to or lower than a lower limit pressure, and
• correct the upper limit pressure such that a ratio between the atmospheric pressure sensed or input by the device and the upper limit pressure becomes a set value set in advance, and correct the lower limit pressure such that a ratio between the atmospheric pressure sensed or input by the device and the lower limit pressure becomes a set value set in advance.