Stepper motor stepper motor is a kind of induction motor, its working principle is the use of electronic circuit, direct current (dc) into time-sharing power supply, multiphase sequential control current, for stepper motor with the current power supply, step motor to work properly, is time-sharing power supply for step motor drive, multiphase timing controller. Although the stepper motor has been widely used, but the step motor and not like a normal dc motor, ac motor under normal use. It must be driven by double annular pulse signal and power circuit of control system can use. So good with step motor is not easy, it involves the mechanical, electrical, electronic and computer and many other professional knowledge. Stepper motor as the executive element, it is one of the key products of electromechanical integration, widely used in all kinds of automation control system. With the development of microelectronics and computer technology, increasing demand for stepper motor, are used in the field of the national economy. Stepper motor efficiency of knowledge only slightly higher than asynchronous motor, the difference in the efficiency of is not very big, because the two there is a certain difference in power, so users tend to model selection of the motor according to the power to determine what motor, such as more than 2000 kw motor selection, users usually consider to choose stepper motor. Stepper motor power, of course, a little higher than asynchronous motor, is not good, because of the difference, also because of stepping type motor have exciting winding and the slip rings, need operation workers have higher level to control excitation. Moreover in the use of asynchronous motor can realize the free maintenance, but the application of stepping motor, but there will be a lot of maintenance work to everyone.