Methods of dynamic balancing
Reason, it is necessary to reassemble the balanced rotating body; All of these situations require on-site dynamic balancing solutions. On site dynamic balancing can include single-sided static balancing and dynamic balancing of flexible rotating bodies.
The method of conducting static balance is very simple. Firstly, a sensor is placed at the additional support of the rotating body (preferably at the shortest distance from the front of the school), in the direction of greater vibration (usually horizontal), and a vibration meter is connected. The rotating body is started to the working speed to record the magnitude of the vibration response. The high reading is X, corresponding to the measured unbalance U, and there is a relationship U=kx. For a rigid rotating body, at a fixed speed, whether it is a hard support or a soft support, k must be a constant, so there must also be a vector relationship U=kx. To determine the angle (or phase) of vector x, the quadratic 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 combined action of the original unbalance U and the calibration unbalance U1=MR. That is, kx1=U+Ut. Rotate the calibration mass M (g) 180 º, reposition it, and start the rotating body again to the same speed and record the vibration response at this time. The high reading is X2, and kx2=U-Ut should be obtained. Therefore, using graphical methods, it is easy to solve the vector equation.
For rotating bodies that require double-sided balancing, on-site dynamic balancing testing instruments that can measure phase should be used. Therefore, a quasi signal generator, commonly photoelectric, should be installed on the rotating body. Some synchronous flashlights triggered by vibration signals at the support can also be used. 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 the horizontal direction) can be observed while synchronizing the internal light.
With its accurate signal, the complex amplitudes XL and XR of the vibration response at the support can be determined, and the magnitude of the unbalance can be calculated using the coefficient influence method. When conducting on-site dynamic balancing, it is usually not known the stiffness matrix or mass matrix of the system, nor is it easy to determine the stiffness or damping 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 inverting the matrix. This method is called the influence coefficient method and has also been widely used in the multi calibration front balance of flexible rotating bodies.
The influence coefficient method is more convenient to operate using complex numbers, and its coefficient matrix elements are also complex numbers. Therefore, the influence of Yin Ni can be considered, unlike soft support dynamic balancing machines or hard support dynamic balancing machines that minimize the Yin Ni of the support and ignore it when separating solutions. The elements of the influence coefficient matrix are numerical values, and during testing, they should be conducted at a fixed speed. As the speed changes, the values of the influence coefficient matrix also change.
Reason, it is necessary to reassemble the balanced rotating body; All of these situations require on-site dynamic balancing solutions. On site dynamic balancing can include single-sided static balancing and dynamic balancing of flexible rotating bodies.
The method of conducting static balance is very simple. Firstly, a sensor is placed at the additional support of the rotating body (preferably at the shortest distance from the front of the school), in the direction of greater vibration (usually horizontal), and a vibration meter is connected. The rotating body is started to the working speed to record the magnitude of the vibration response. The high reading is X, corresponding to the measured unbalance U, and there is a relationship U=kx. For a rigid rotating body, at a fixed speed, whether it is a hard support or a soft support, k must be a constant, so there must also be a vector relationship U=kx. To determine the angle (or phase) of vector x, the quadratic 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 combined action of the original unbalance U and the calibration unbalance U1=MR. That is, kx1=U+Ut. Rotate the calibration mass M (g) 180 º, reposition it, and start the rotating body again to the same speed and record the vibration response at this time. The high reading is X2, and kx2=U-Ut should be obtained. Therefore, using graphical methods, it is easy to solve the vector equation.
For rotating bodies that require double-sided balancing, on-site dynamic balancing testing instruments that can measure phase should be used. Therefore, a quasi signal generator, commonly photoelectric, should be installed on the rotating body. Some synchronous flashlights triggered by vibration signals at the support can also be used. 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 the horizontal direction) can be observed while synchronizing the internal light.
With its accurate signal, the complex amplitudes XL and XR of the vibration response at the support can be determined, and the magnitude of the unbalance can be calculated using the coefficient influence method. When conducting on-site dynamic balancing, it is usually not known the stiffness matrix or mass matrix of the system, nor is it easy to determine the stiffness or damping 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 inverting the matrix. This method is called the influence coefficient method and has also been widely used in the multi calibration front balance of flexible rotating bodies.
The influence coefficient method is more convenient to operate using complex numbers, and its coefficient matrix elements are also complex numbers. Therefore, the influence of Yin Ni can be considered, unlike soft support dynamic balancing machines or hard support dynamic balancing machines that minimize the Yin Ni of the support and ignore it when separating solutions. The elements of the influence coefficient matrix are numerical values, and during testing, they should be conducted at a fixed speed. As the speed changes, the values of the influence coefficient matrix also change.
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