yd series three-phase multi-speed induction motors are one of the derived series of y series induction motors to our national unified designing, they offer distingnishing features of excellent performance, attractive appearance and detter interchangeaditity for the same kind of products abroad. the protection class is ip44. 　 the motors are designed in three types i.e. double speed, three speed and four speed. these speed rotes can be changed in stages. the motors find wide applications in the equipments where the changed rates in stages are needed, such as mechanism, mine, metallurgy, texitiles, printing and dyeing, chemical industry, agricultural machinery, etc. they cal also simplify or take the place of reduction gearbox in the mechanical drive.