Why Do Motors Have Double Squirrel Cage Rotors?

In the design process of the motor to ensure that the performance of the motor meets the requirements of the premise, should strive to simplify the manufacture of manufacturing, but in order to meet the special operating requirements, often need to design links to take the necessary measures.

For squirrel cage motors, starting is always a very critical performance requirements, how to solve the starting performance and other performance correlation is very important. In order to improve the starting performance of squirrel cage motors, we have talked about the deep groove rotor, and today our topic circles in the double squirrel cage rotor motor.

Double squirrel cage is the rotor part including two cages, that is, an inner squirrel cage, for the operation of the cage, the other for the outer squirrel cage, for the starting cage, the outer cage guide bar area is smaller. Common double squirrel cage rotor there are two kinds, one is the copper double cage, the starting cage guide material using resistance coefficient of brass or bronze, running cage guide material for diesel copper. Another is the use of cast aluminum way to realize the double squirrel cage.

Double squirrel cage motors also utilize the skin effect to improve the starting performance of the motor, when the motor starts, the current mainly passes through the outer cage, in view of the area of the outer cage guide strip and the special characteristics of the material, effectively limiting the starting current and ensuring the starting torque.

Double squirrel-cage motors have good operating characteristics, have a large starting torque, can be started with the rated load, and, at the same time, the motor can have a high speed under the rated load.

Compared with the deep groove rotor, the adjustment of the diameter-height distance between the inner and outer squirrel cage, and the area and shape of the inner and outer cage guide strips in the groove of the double squirrel cage rotor is an effective variable to optimize the performance parameters of the motor, so as to realize the design requirements of different load characteristics, which is the advantage of the double squirrel cage motor.

However, in view of the fact that the rotor leakage reactance of the double squirrel-cage motor is larger, its corresponding motor power factor and maximum torque will be reduced to different degrees.

In addition to the typical deep groove and double squirrel cage rotor, in order to improve the starting problems of the squirrel cage motor, big belly small mouth bottle-shaped groove, trapezoidal groove and "convex" groove.

Above we talked about is the design of the motor groove shape comparison but from the manufacturing process point of view analysis, the theoretical advantages are not necessarily realized in the process. For motor products, we have experienced a unified design process, especially when then, we are particularly cautious about the changes in the unified design, but under these conditions, the same program of the motor, the final quality level of good and bad. Similarly, to improve the starting performance of the motor groove improvement measures, must be matched with the manufacturer's technology level, equipment level.