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How to analyze and judge the quality of cast aluminum rotor?
- Jan 31, 2019 -

How to analyze and judge the quality of cast aluminum rotor?

The quality of the cast aluminum rotor affects the efficiency, power factor, and starting and running performance of the motor. In order to comprehensively improve the quality of the rotor, it is necessary not only to analyze the defects of the cast aluminum rotor, but also to study various factors affecting the quality of the cast aluminum rotor, and propose improvement measures. In this paper, Ms. introduces some brief introductions to the rotor cast aluminum method and dissecting the broken strip problem.

Rotor cast aluminum is a hidden project. The quality control of the rotor is guaranteed by the process parameters. In a sense, the performance quality of the cast aluminum rotor is concentrated on the cast aluminum of the rotor.

Cast aluminum method and rotor quality

After the squirrel-cage rotor is changed from a copper strip to a casting method, the stray loss of the motor is increased by 2 to 6 times. The cast aluminum method of the rotor is different, and the stray loss is also different. When a pressure cast aluminum rotor is used, the stray loss of the motor is the largest. Centrifugal cast aluminum and vibrating cast aluminum are susceptible to defects due to various factors, but the stray loss of the rotor is small. Further research found that the density of the die-cast rotor is about 8% lower than that of the centrifugal cast aluminum rotor aluminum cage, and the average resistivity is increased by 13%, which makes the main technical and economic indicators of the asynchronous motor of the die-cast rotor deteriorate, core loss, slip rate, The temperature rise is increased, while the minimum torque and efficiency are reduced.

The density of the aluminum in the die-casting rotor is reduced, and the electric resistance is increased because the gas mixed in the die-casting is densely packed in the shape of a pinhole in the rotor cage, the end ring, the fan blade, and the like. Also due to the strong pressure, the cage and the core are in close contact (even if the aluminum conductor is also scattered between the core laminations), the lateral current greatly increases the stray loss of the motor.

The low-pressure cast aluminum-aluminum water comes from the inside of the crucible and adopts a relatively "slow" low-pressure casting, the exhaust is better, and the quality of the cast aluminum rotor is good. The quality of the low-pressure cast aluminum rotor is the best, followed by centrifugal casting of aluminum, and the worst is pressure-cast aluminum.

The defects of cast aluminum rotors are varied, and the causes are also complicated. Domestic motor factories mostly use centrifugal aluminum, and the following mainly analyzes the quality problems of centrifugal cast aluminum rotors. Some quality issues with other cast aluminum methods are briefly described.