The reason is that the balanced rotating body needs to be reassembled; All of these situations require on-site dynamic balancing to be resolved. On site dynamic balancing can include single side static balancing and dynamic balancing of flexible rotating bodies.
The method of static balance is very simple. Firstly, at the additional support of the rotating body (preferably the shortest distance from the front of the calibration), a sensor is placed in the direction of high vibration (usually the horizontal direction), and a vibration meter is connected. Start the rotating body and record the vibration response at the working speed. The high reading is X, which corresponds to the measured unbalance U, and there is a relationship formula U=kx. For a rigid rotating body, whether it is a hard support or a soft support, k must be a constant at a fixed speed, so there must be a vector relationship formula U=kx. To determine the angle (or phase) of vector x, the twice rotation method can be used for measurement and calculation. Place a calibration mass M (g) at any position with a radius of R (mm) on the rotating body, then start the rotating body to the same speed and record the vibration response at this time. The high reading is x1. Obviously, x1 is the result of the joint action of the original unbalance U and the calibration unbalance U1=MR, that is, kx1=U+U. Rotate the calibration mass M (g) 180 º, then restart the rotating body to the same speed and record the vibration response at this time. The high reading is X2, and there should be kx2=U-Ut. Therefore, using graphical methods, it is easy to solve the vector equation.
For rotating bodies that require double-sided balance, on-site dynamic balance testing instruments capable of measuring phase should be used. Therefore, a quasi signal generator is required to be set on the rotating body, commonly using photoelectric methods. There are also synchronous flashlights triggered by vibration signals at the support. Due to the visual pause phenomenon of the human eye, the observed rotating body is in a stationary state. It is necessary to set angle markers such as 0 °, 90 °, 180 °, etc. on the front of the school in advance, so that the angle between the set 0 ° angle marker and a fixed position (such as horizontal direction) can be observed under synchronous internal light.
With its quasi signal, the complex amplitudes XL and XR of the vibration response at the support can be determined, and the magnitude of the imbalance can be calculated using the coefficient influence method. When conducting on-site dynamic balancing, the stiffness matrix or mass matrix of the system is usually not known, and it is not easy to determine the stiffness or Yin Ni characteristics of the support in order to further simplify the dynamic stiffness matrix. In this case, the dynamic flexibility matrix of the system can be obtained through experimental methods, and then the stiffness matrix can be obtained by calculating the inverse matrix. This method is called the influence coefficient method, which is also widely used in the multi calibration front balance of flexible rotating bodies.
The influence coefficient method is more convenient to use complex numbers for operation, and its coefficient matrix elements are also complex, so the influence of the support can be considered, unlike soft support dynamic balancing machines or hard support dynamic balancing machines, which try to minimize the support of the support and ignore it at the separation solution. The elements of the influence coefficient matrix are numerical values, and testing should be conducted at a fixed speed. If the speed changes, the value of the influence coefficient matrix will also change.
The method of static balance is very simple. Firstly, at the additional support of the rotating body (preferably the shortest distance from the front of the calibration), a sensor is placed in the direction of high vibration (usually the horizontal direction), and a vibration meter is connected. Start the rotating body and record the vibration response at the working speed. The high reading is X, which corresponds to the measured unbalance U, and there is a relationship formula U=kx. For a rigid rotating body, whether it is a hard support or a soft support, k must be a constant at a fixed speed, so there must be a vector relationship formula U=kx. To determine the angle (or phase) of vector x, the twice rotation method can be used for measurement and calculation. Place a calibration mass M (g) at any position with a radius of R (mm) on the rotating body, then start the rotating body to the same speed and record the vibration response at this time. The high reading is x1. Obviously, x1 is the result of the joint action of the original unbalance U and the calibration unbalance U1=MR, that is, kx1=U+U. Rotate the calibration mass M (g) 180 º, then restart the rotating body to the same speed and record the vibration response at this time. The high reading is X2, and there should be kx2=U-Ut. Therefore, using graphical methods, it is easy to solve the vector equation.
For rotating bodies that require double-sided balance, on-site dynamic balance testing instruments capable of measuring phase should be used. Therefore, a quasi signal generator is required to be set on the rotating body, commonly using photoelectric methods. There are also synchronous flashlights triggered by vibration signals at the support. Due to the visual pause phenomenon of the human eye, the observed rotating body is in a stationary state. It is necessary to set angle markers such as 0 °, 90 °, 180 °, etc. on the front of the school in advance, so that the angle between the set 0 ° angle marker and a fixed position (such as horizontal direction) can be observed under synchronous internal light.
With its quasi signal, the complex amplitudes XL and XR of the vibration response at the support can be determined, and the magnitude of the imbalance can be calculated using the coefficient influence method. When conducting on-site dynamic balancing, the stiffness matrix or mass matrix of the system is usually not known, and it is not easy to determine the stiffness or Yin Ni characteristics of the support in order to further simplify the dynamic stiffness matrix. In this case, the dynamic flexibility matrix of the system can be obtained through experimental methods, and then the stiffness matrix can be obtained by calculating the inverse matrix. This method is called the influence coefficient method, which is also widely used in the multi calibration front balance of flexible rotating bodies.
The influence coefficient method is more convenient to use complex numbers for operation, and its coefficient matrix elements are also complex, so the influence of the support can be considered, unlike soft support dynamic balancing machines or hard support dynamic balancing machines, which try to minimize the support of the support and ignore it at the separation solution. The elements of the influence coefficient matrix are numerical values, and testing should be conducted at a fixed speed. If the speed changes, the value of the influence coefficient matrix will also change.
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