YD series pole-changing multi-speed three phase asynchronous motors are ong of the main derivatives of the same type. They have step changes of rotationalspeed to meet the requirement of load character, so that they obtain the advantages of suitable matching of power and simplify speed changing systems. for this reason they are worth calling ideal motive power for saving energy consumption in mechanical systems. They are widely used in such industrial and agricultural departments, as machine tools, mining metallurgy, spinning and dyeing, chemical industry, and agricultural machinery, etc.

YD series motors have such advantages over other domestic series electric machines of similar types, as high efficiency, high starting torgue, low noise, low vibration, etc. So they are the very elevtric machines of the last word in saving power consumption.
　　
YD series motors can match other foreign advanced machines of similar types in power grades as well as in correspondent relationship between power grades and mounting dimensions, and therefore they can substitute for the latter so as to be usedto fit machine tools oras ingle motors for export as well as spare motors for electric machines of similar types in import as well as spare motors for electric machines of simelar types in imported equipment.