Auto-coupling main and auxiliary windings with different voltage step-down speed regulation circuit

As shown in the figure, the autotransformer TA applies different voltages to the main and auxiliary windings LR and LA respectively to perform voltage reduction and speed regulation. The use of autotransformer TA to reduce voltage and speed regulation can greatly improve the starting performance and power consumption of the motor. The disadvantage is that adding an autotransformer increases the size and cost of the whole machine.