YT0638 power controller is composed of servo motor, control circuit, autotransformer (or compensation transformer), with the advantages of small size, light weight, high efficiency, wide voltage range, no waveform distortion and so on. With over-voltage (under-voltage) protection, delay (select) protection and fault protection and other functions, two-way voltage instructions, complete functions, safe and reliable. Widely used in household electricity and industrial and agricultural production, scientific research and health care.