20BY permanent magnet stepping motor is controlled by electric pulse signal, then it change electric pulse signal into angular displacement. The motor is widely used in figure control system, so it is suitable for portraying machinery, automatic record apparatus and so on. It’s structure is jaws mode with the property of little dimension, low-weight. It’s insulation class is E. The motor altered from SM30-2001 is homemade , which has been introduced from Japan recently.