Introduction 
 With the development of electronic technology, the AC inverter system is also developing rapidly. In order to meet the demands of the market, our company developed the Y2VP series three phase inverter duty asynchronous motor on the basis of widely investigation and research. Each of its performance indexes is equivalent to the international Standard of IEC 60034.15 and Chinese National Standard GB755. It has advantage of low noise, less vibration, wide speed-adjusting range, new and beautiful appearance.                                                                                                                   Y2VP motor is special designed to match high performance IGBT pulse-width modulated inverter, it does not need to connect external filters when using.                                    By collecting the advantages from the same kind of products both at home and abroad, Y2VP motor is designed by means of CAD technique. In order to make the motor to be suitable for the power supply condition for PWM frequency-changing power supply, special consideration has been made for the stator slot shape and rotor slot shape, and the distribution type of stator winding when designing, to acquire proper inductance value to suppress and reduce the reverse influence of time harmonic waves, and space harmonic waves caused by other causes, a definite margin is also considered when design the electric and magnetic load. Thus, the overload capability at high frequency can still be maintained when running at low frequency.                                                When designing the insulation structure of Y2VP series 3-phase frequency-changing speed-adjusting asynchronous motor, influence of high chopping frequency when using IGBT in PMW inverter has been considered, especially its turn-to-turn insulation strength. For withstanding the severe impulse voltage with great gradient, repeatedly applied on turn-to-turn caused by high voltage increasing rate, special measures for strengthening the insulation has been taken. Turn-to-turn withstanding voltage of the motor is far higher than the value specified for AC motor in JB/Z346-89.                                             In structure design, mounting dimensions of Y2VP series motor is the same as that of Y2 series. There are two kind of cooling mode for Y2VP motor: one is IC411 series. It can ensure this series of motor to realize the speed-adjusting at constant torque and at constant power, and ensure the long time operation in this condition with winding temperature rise not exceeding permitted value. The other one is IC416 series; in this series forced ventilation by independent axial air fan is used; it ensures the motor to be capable of long time running at low speed(5HZ) under constant torque with temperature rise not exceeding permitted value.                                                                            When making routine test and type test for Y2VP, the motor is powered through inverter. It is in conformity with its actual operation condition.