Usually, a rotor is designed so that it is axisymmetric relative to the axis of rotation. However, due to a series of factors in the machining process, the final assembled rotor cannot achieve complete axisymmetric driving force, resulting in a certain amount of imbalance. This type of rotor imbalance is generally referred to as the initial imbalance.
Figure 1 Unbalance of a disc
If a rotor is divided into thicknesses of Δ For the original piece of z, there is an imbalance in each piece (as shown in Figure 1). Identify the existence of an unbalanced mass of size G at a radius of r and a circumferential reference angle of α The centrifugal force generated is:
In the equation ω Is the angular velocity. Visible centrifugal force F varies with ω As the square of increases, it increases. So the product of G and r is called an imbalanced quantity, which is generally expressed as | U | Gr=(or abbreviated as U=Gr). The unit is usually g/mm, then:
Therefore, the centrifugal force is directly proportional to the imbalance, which belongs to the vector of the direction and is usually expressed in engineering as:
Due to the varying magnitude and direction of the imbalance of each disc (as shown in Figures 2 and 3), the imbalance of the rotor is a function of the axis coordinates. Because the article focuses on adjusting the dynamic balance of the impeller, no detailed description will be provided here.
What are the key factors that cause initial imbalance? The technician of Shenman Balancing Machine will analyze for you:
1. Unevenness of rotor material:
2. Unbalance of coupling:
3. Imbalance caused by asymmetric keyways.
4. During rotor machining, certain roundness errors and eccentricities are always caused;
5. Impeller imbalance hazard;
The imbalance caused by these factors is random and cannot be calculated. Therefore, it needs to be measured and corrected according to gravity tests (static balance) and rotational tests (dynamic balance) to reduce it to the allowable level.
Figure 1 Unbalance of a disc
If a rotor is divided into thicknesses of Δ For the original piece of z, there is an imbalance in each piece (as shown in Figure 1). Identify the existence of an unbalanced mass of size G at a radius of r and a circumferential reference angle of α The centrifugal force generated is:
In the equation ω Is the angular velocity. Visible centrifugal force F varies with ω As the square of increases, it increases. So the product of G and r is called an imbalanced quantity, which is generally expressed as | U | Gr=(or abbreviated as U=Gr). The unit is usually g/mm, then:
Therefore, the centrifugal force is directly proportional to the imbalance, which belongs to the vector of the direction and is usually expressed in engineering as:
Due to the varying magnitude and direction of the imbalance of each disc (as shown in Figures 2 and 3), the imbalance of the rotor is a function of the axis coordinates. Because the article focuses on adjusting the dynamic balance of the impeller, no detailed description will be provided here.
Figure 2 Unbalance of a rotor
What are the key factors that cause initial imbalance? The technician of Shenman Balancing Machine will analyze for you:
1. Unevenness of rotor material:
2. Unbalance of coupling:
3. Imbalance caused by asymmetric keyways.
4. During rotor machining, certain roundness errors and eccentricities are always caused;
5. Impeller imbalance hazard;
The imbalance caused by these factors is random and cannot be calculated. Therefore, it needs to be measured and corrected according to gravity tests (static balance) and rotational tests (dynamic balance) to reduce it to the allowable level.
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