The SVC high-performance fully-automatic AC voltage-stabilized power supply is composed of such components as a contact-type self coupling voltage stabilizer, a servo motor and an automatic control circuit, which is a popular type of the AC voltage-stabilized power supply that uses a servo motor to drive the carbon brush to change the number of the coil turns of the speed regulator to complete the voltage stabilization function. When the grid voltage is not stable or the load power changes, the automatic control circuit drives the servo motor according to the output voltage change and adjusts the position of the carbon brush in the contact-type self coupling voltage stabilizer to adjust the output voltage to the rated value, so as to achieve the automatic voltage stabilization. This series power supply, characteristic of such advantages as wide voltage stabilization range, high precision, no additional distortion in the output waveform, high efficiency and strong load adaptability, is widely used such electric equipment as computers and their peripheral locations, medical electronic equipment, radio communication and broadcasting equipment, air-conditioning and industrial production lines and is widely used as well in the household electric appliances for the voltage stabilization and protection.