A Guide to Balance Qualilty Grades

The chart below is designed to give an overview of the balance quality grades for various groups of representative rigid rotors.

Note:  Some groups of rotors, not included in the official ISO table, are added and reported in Italic type form.

Balancing quality grade is show in G mm/s

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0,4    Gyroscopes
         Spindles, discs and armatures of precision grinders
         Textile fuses

1,0    Small electric armatures with special requirements
         Tape recorder and phonograph (gramophone) drives, cine projectors
         Grinding machine drives
         Turbines  and Compressors with special requirements

2,5    Gas and steam turbines, including marine main turbines  (merchant service)
         Turbine driven pumps
         Rigid turbo generator rotors
         Turbo compressors
         High speed compressors and aeronautic compressors
         Medium and large electric armatures with special requeriments
         High quality household electric armatures, dentist drills and textile components
         Small electric armatures not qualifying for one or both of the conditions specified
         for small electric armatures of balancing quality grade G 6,3
         Machine tool drive
         Air conditioning fans for hospitals and concert halls
         High speed gears(over 1000 RPM) of marine turbines .
         Computer memory drums and discs

6,3    Small electric armatures, often mass produced, in vibration insensitive applications, and/or
          with vibration isolating mountings.
          Medium and large electric armatures (of electric motors having at least 80 mm shaft height )
          without special requirements
          Machine tool and general machinery parts
          Parts of process plant machines, Centrifuge drums, decanters, washers
          Hydraulic machine rotors
          Fly wheels, Fans; Pump impellers
          Marine main tuebine gears (merchant service )
          Paper machinery rolls; print rolls
          Assembled aircraft gas turbine rotors
          Individual components of engines under special requirements

16      Drive shafts (propeller shafts, cardan shafts) with special requirements
          Parts of agricultural machinery, parts of crushing machines
          Individual components of engines (gasoline or diesel) for cars ,trucks and locomotives
          Crankshaft / drives of engines with six or more cylinders under special requirements
          Low speed separators
          Light boat impellers)
          Motor bicycle and car wheels
          Normal transmission pulley
          Wood machine tools

40      Car wheels, wheel rims, wheel sets and drive shafts
          Crankshaft / drives of elastically mounted fast four cycle engines (gasoline or diesel ) with
          six or more cylinders (pistons speed greater than 9 m/s)
          Crankshaft /drives of engines of cars , trucks and locomotives

We hope that you will find this information useful - please get in touch with the specialist balancing team at Cemb Hofmann UK on 0161 872 3123 should you have any queries regarding this table or any other aspect of balancing.

Please visit our site: www.cembhofmann.co.uk for more information about balancing machines and sub contract balancing services.