Identify the motor ventilation structure through the rotor

High-voltage and low-voltage high-power motors, whether radial or mixed ventilation structure, the rotor shaft for the most panels, round welded shaft, that is, iron stent shaft structure. According to the different ventilation structure, the axis of the baffle position is different, and the baffle size is also different, air recognition from these differences began. The axial channel between the radial ventilated iron support bracket shaft and the rotor core is symmetrical in the center of the rotor core to prevent the inlet air from interfering with each other.

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Axial Ventilation Purely Axial Ventilation The stator has no radial ducts and no axial baffles. One end of the shaft-radial mixed ventilation rotor is installed with a centrifugal fan larger than the outer diameter of the rotor, and the other axial support of the iron support shaft and the rotor core is blocked, forcing the cooling medium-air to flow through the axial thoroughfare and folding Ventilation path to the stator radial, concentrated in the base, between the stator core wind collection set, out of the heat window row to the surrounding environment.

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Discussion on the structure of air duct

Asynchronous motor commonly used three kinds of cooling air duct structure, namely axial ventilation, radial ventilation, axial - radial mixed ventilation, the core length direction of the winding temperature distribution at different points, how to choose should be taken into account the motor capacity, Poles, speed, core length and set, the rotor core, the outer diameter size and other parameters, processing costs and other factors can not be ignored.


Axial ventilation structure

 General ventilation structure. Centrifugal fans are installed on one end of the motor. The stator core is not provided with radial air ducts. The cooling air flows in the axial direction after entering the non-fan end.


Radial ventilation structure

 Cooling air enters symmetrically from both sides. The main part of the cooling air through the stator coil end → rotor choke air duct → rotor radial air duct → air gap a stator radial duct, and finally discharged through the stator core middle.

Shaft - radial mixing ventilation structure

 There are two main ways to adopt axial-radial hybrid ventilation:

Centrifugal fan installed on the motor side. Cooling air mainly through the rotor u part of the air duct → rotor air duct → air gap → stator air duct a stator coil straight part of the stator core air duct surface of the stator coil end → cooling fan, and finally discharged, this ventilation is still One end into the wind, the other end of the wind, the iron core should not be too long.


2 pole motor ventilation structure

 Install axial fans on both sides of the motor. Axial-radial mixing ventilation (both sides) of the air path, the stator slot ventilation, which greatly increased the air gap in the air flow. The number of rotor vents is much less than the number of stator vents, which is to avoid excessive wind speed and excessive noise at high speeds. The rotor air duct is concentrated in the middle of the iron core. When the cooling air flows from the rotor radial air duct into the radial air duct of the stator, a larger part axially flows through the air gap to further improve the cooling effect.

Baffle does not meet the requirements of the consequences

In the actual production process, the compliance of the baffle is not good, or the baffle axial position does not conform, or the baffle height is not qualified, will lead to the motor running the air duct does not meet the requirements, the direct result is the motor temperature L does not meet, but also some individual motor will appear ventilation noise.