Energy saving technique for natural stone cutting machine by constant speed control in stone industry

Abstract

This study presents a constant speed control technology applied to manufacturing process equipment. According to the amount of change in electrical motor (EM) load, a Silicon Controlled Rectifier element was used to modulate the phase angle so that the current drops accordingly, to meet the most appropriate output voltage of the EM, providing the machine with the best torque output. The changes in output power of the EM varied along with different process loads, so unnecessary electricity at low loads of EM can be saved; however, when the equipment undergoes a period of high-load operation, the proposed technique provides an appropriate torque, thus reducing power consumption. The present energy-saving technique by constant speed control (ESTCSC) does not affect the machine, as it only modulates the load according to the dynamic load variation of the machine. In this study, the proposed ESTCSC was practically applied to a sawing machine in the stone industry. The validation experiments were conducted w/o installing the ESTCSC, and the measured total saving rates for operating current, average operating power consumption, and 24 h long-term energy consumption were 20, 38.87, and 48.36%, respectively.