Why is the blower motor with fan easy to break the shaft?

- Oct 14, 2019-

High risk factors for blower motor with fan shaft breaking

When the blower motor with fan is running, the impeller dust generates an exciting force, and the surge under the fault condition generates an additional impact load. The two factors cause the blower motor with fan to easily break the shaft.

Impeller dust problem

When the fan starts working, the vibration of the bearing part is very small, but with the lengthening of the running time, the dust inside the fan will not uniformly adhere to the impeller, gradually destroying the dynamic balance of the fan, so that the bearing vibration gradually increases, once the vibration reaches the fan The maximum allowed, the fan must be shut down for repair.

Surge problem

The fan has periodic airflow and backflow, and the flow is repeated periodically, causing the turbine itself to vibrate. At the same time, the noise of the fan works. When the surge is severe, it may cause damage to the equipment and bearings and cause an accident.

The motor is broken due to the matching problem

If the assembly fit between the drive motor and the high-pressure blower is good, the output shaft of the drive motor is only subjected to the rotational force (torque), and the operation will be smooth and without pulsation. At different times, the drive motor output shaft is also subjected to radial forces from the input of the high pressure blower. The effect of this radial force will cause the output shaft of the drive motor to be forced to bend, and the direction of the bend will change as the output shaft rotates.

If the error of concentricity is large, the radial force causes the local temperature of the output shaft of the motor to rise, and the metal structure is continuously destroyed, which will eventually cause the output shaft of the drive motor to be broken due to local fatigue. The greater the error between the concentricity of the two, the shorter the time for the output shaft of the drive motor to break.

While the output shaft of the drive motor is broken, the high-pressure blower input also receives radial force from the output shaft of the drive motor. If this radial force exceeds the maximum radial load that the high-pressure blower input can withstand, The result will also result in deformation or even breakage at the input of the high pressure blower or damage to the input support bearing.

Quality defect leads to broken shaft

The sharp angle of the machining undercut causes a stress-concentrated break! The roughness of the convex portion of the fracture surface is the origin of the stress concentration, and the fracture is the first.

Possible reasons are as follows: 1. The arc of the undercut is too small or has burrs and sharp angles; 2. The motor pulley has a large jump and the jitter is broken; 3. The overheating or overheating of the quenching and tempering, the carbide of the hot rolled steel bar is Band or mesh may also cause shaft breakage.