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Entry type: FAQ Entry ID: 38717428, Entry date: 10/02/2009

What do we understand by balance quality?

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What do we understand by balance quality?







DIN ISO 1940-1 specifies criteria for assessing the state of balance of rotating rigid bodies. Balance quality levels are defined here to enable classification by different levels of requirements placed on the accuracy of the balancing. Each quality level (identification letter G) is characterized by a numerical value of, for example G 2.5
ezul x ω =  const. [mm/s]
ezul =  referenced residual unbalance in mm
ω =  angular velocity of the rotor in s-1






The balance quality is assigned to different types of rotors, and experience has shown that this results in satisfactory smooth running of the machine. For rotors from electric motors, the balance quality G 6.3 is recommended for n=950 1/min and
G 2.5 is recommended for n>950 1/min

The balancing can be modified by operational influences.




    The following are particularly prone to unbalance:
  • Motors in dusty plant operations at high levels of humidity due to one-sided deposits on the fan
  • Fan wheels, whose welded constructions are subjected to deformations and whose tension is released due to centrifugal forces and high temperatures
  • Exhaust gas fans onto which flying ashes stick and/or pieces of ash flake
  • Pumps for chemically aggressive substances through uneven corrosion



In the case of drives which are prone to unbalance, a regular checking is recommended to ensure smooth running of the machines.




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