In this study, a constant frequency control technique is proposed for improving the overall power efficiency of a squirrel-cage AC induction motor, so that the induction motor can maintain its original operating state under low energy consumption. In this study, a semiconductor component, the Silicon Controlled Rectifier (SCR), was used as the component for adjusting the voltage phase trigger, and a constant frequency control module was developed to trigger the SCR through the output signals. The experiment records the energy consumption of the rated voltage operation of 0.47 kWh in 4 cycles, and the energy consumption of the voltage adjusting operation is 0.402 kWh. The calculated energy saving rate is about 12%. In addition, the power factor (PF) of the tested induction motor was increased from 0.44 to 0.53 at a low load, which is increased by 22.1%, while the PF of the overall low and high load is increased by about 12.9%. This study improves the conversion effect of converting the overall apparent power (kVA) to active power, to verify the energy-saving effect on the modulation of the voltage input of the squirrel-cage AC induction motor. (C) 2019 Elsevier Ltd. All rights reserved.