TORQUE CONTROL TYPE CLOSED COMPRESSOR

摘要

PURPOSE:To reduce the variation of a rotating speed of a rotary part and to reduce the vibration of a closed vessel in its rotating direction by controlling a power supply so that torque variation similar to the absorbing torque of a compressing element in one rotation of a main shaft is generated by a motor element. CONSTITUTION:When a compressure is driven, pressure variation in a working room is detected and its detecting signal is sent to a computing element. The computing element finds out the variation of gas torque on the basis of the input signal and sends a control signal to a control part so that torque matched with the changes state is outputted by a motor element. The control part generates a command signal for changing a current or voltage to be supplied from a power supply frequency varying device to the compressor. The power supply frequency varying device can change output power in addition to the change of the rotating speed of the compressor. Since the electromagnetic torque of the motor element stored in a compressor case can be changed in accordance with the level of a current supply or voltage supply, the electromagnetic torque corresponding to the load torque of the compressor can be outputted.