Analysis Of The Causes And Serious Consequences Of Overheating Of Cast Aluminum Rotors

Analysis of the Causes and Serious Consequences of Overheating of Cast Aluminum Rotors

Relative to the wire-wound rotor motor, cast aluminum rotor motor safety performance is better, the theoretical electrical failure rate is half of the wire-wound rotor motor. However, some special conditions, specific purposes of the motor, for some manufacturing process defects are particularly sensitive to the cast aluminum rotor overheating, the electrical failure of the cage bar melting chances are also very high.

Problems in the Casting Chain

Whether it is high-pressure aluminum casting, low-pressure aluminum casting, or centrifugal aluminum casting process, there are some inherent defects, such as casting process quality monitoring is relatively difficult, the process parameters are difficult to quantify, the operator tends to rely on the experience of the set parameters; porosity, trachoma and other manufacturing defects are very hidden, most of them occur in the internal, pre-checking test can not be found, and only the motor is actually running, the defects of the impact will be exposed. Especially in some of the load changes in the range of large, high speed applications, there will often be thrown aluminum, rotor wind blade due to overheating occurs softening and twisting phenomenon, rotor overheating blue and other issues.

Motor operation process, the rotor itself and the stator part of the heat radiation may lead to rotor local or overall overheating blue problem. Rotor all blue, the temperature rise of the motor is generally very high, when the rotor local overheating, more due to the rotor itself casting quality, such as the more typical is thin strip, broken strip and other issues, serious because of overheating and flow aluminum phenomenon, that is, the rotor guide part of the high temperature melting from the groove out of the mouth, and accompanied by sweeping the quality of the failure.

Rotor End Deformation Problems

For most of the cast aluminum rotor, due to the aluminum casting process, ventilation and heat dissipation and post-balance and many other factors, the rotor aluminum end of the ring parts with balance column and wind blade, when the motor rotor temperature is high, the rotor in the aluminum will occur to varying degrees of fluidization and deformation, especially at the end of the rotor, unlike the guide bar by the rotor groove constraints in the state of high-rpm is likely to be a serious distortion of the deformation of the final state of the wirewound. The final state is similar to that of the wire-wound rotor, all the wind blades are thrown out of the stator winding friction, resulting in instantaneous destruction of the entire motor.