WCBF type standard telescopic flange coupling due to various reasons makes its center of mass or inertial main axis do not coincide with the axis of rotation. Unbalanced centrifugal inertial force, centrifugal inertial couple force and dynamic deflection (vibration shape) will occur during operation. , Known as the unbalance phenomenon of the rotor, this unbalance phenomenon will inevitably cause the vibration of the shaft system, thereby affecting the normal operation and service life of the machine, so it should be paid attention to.The degree of unbalance (unbalance U) is usually expressed by the product mr of the mass m of the rotor and the distance r from the center of mass to the axis of rotation of the rotor, which is called the product of mass diameter.It is also expressed by the product of mass diameter per unit mass, called the eccentricity e (not geometrically eccentric.) The product of mass diameter mr is a relative quantity related to the mass of the rotor, while the eccentricity e is a value that has nothing to do with the mass of the rotor.的量。 The amount.The former is relatively intuitive and is often used for specific balancing operations of a given rotor, while the latter is used to measure the pros and cons of the rotor balance or to check the balance accuracy. The balance grade standard of the coupling is evaluated by e.For a flexible rotor, use the mode eccentricity (the nth mode) en=Un/mn, and Un and mn are the nth mode and the first mode quality respectively.