ISO Balancing Standards – G Balancing Quality Classes
The G balance quality classes, defined within the scope of ISO standards, have been developed to ensure that rotating parts operate safely, efficiently, and for a long time. These classes determine the permissible residual imbalance levels depending on the rotor type and operating conditions.
Each G quality class represents the maximum vibration speed that is acceptable for a rotating workpiece. Increasing the class number indicates a less restrictive balance standard with wider tolerances. This structure allows for the correct selection of the balance level suitable for the needs of rotors used in different industrial applications.
MBS Balans offers customized and high-precision balancing solutions for each application, based on these internationally valid ISO standards. Thanks to the measurement and balancing processes carried out in accordance with G balance quality classes, the vibration levels of the equipment are minimized, performance is increased, and operational reliability is maximized.
| Grade G (mm/s) | Balanced Rotor Examples |
|---|---|
| 4000 | Crankshaft drives for large, slow marine diesel engines (piston speed below 9 m/s), inherently unbalanced |
| 1600 | Crankshaft drives for large, slow marine diesel engines (piston speed below 9 m/s), inherently balanced |
| 630 | Crankshaft drives, inherently unbalanced, elastically mounted |
| 250 | Crankshaft drives, inherently unbalanced, rigidly mounted |
| 100 | Complete reciprocating engines for cars, trucks and locomotives |
| 40 | Cars; wheels, wheel rims, wheel sets, drive shafts, crankshaft drives, inherently balanced, elastically mounted |
| 16 | Agricultural machinery crankshaft drives, inherently balanced, rigidly mounted; crushing machines; drive shafts (cardan shafts, propeller shafts) |
| 6.3 | Aircraft gas turbines; centrifuges (separators, decanters); electric motors and generators (shaft height ≥ 80 mm, maximum rated speeds up to 950 r/min); electric motors with shaft heights smaller than 80 mm; fans; gears; general machinery; machine tools; paper machines; process plant machines; pumps; turbochargers; water turbines |
| 2.5 | Compressors; computer drives; electric motors and generators (shaft height ≥ 80 mm, maximum rated speeds above 950 r/min); gas turbines and steam turbines; machine-tool drives; textile machines |
| 1 | Audio and video drives; grinding machine drives |
| 0.4 | Gyroscopes; spindles and drives of high-precision systems |