In rotating machinery, any mass that is not perfectly centered on the shaft creates an unbalance force that varies sinusoidally with rotation speed. This unbalance manifests as vibration, which can reduce bearing life, increase noise, and cause premature failure.
The magnitude of the unbalance is described by the product of the unbalance mass (M) and its radial distance from the axis of rotation (r). By adding a correction mass (mc) at a known radius (R) on the opposite side of the rotor, the net centrifugal force can be minimized.
For singleβplane balancing, the required correction mass is calculated using a simple proportional relationship: the moment of the original unbalance (MΒ·r) must be countered by the moment of the correction mass (mcΒ·R). This yields the classic formula shown below.
How do I calculate the magnitude of unbalance in a rotating system?
What is the purpose of adding a correction mass to a rotor?
How do I determine the location for placing the correction mass?
What are the effects of unbalance in rotating machinery?
Can you explain how the correction mass affects the system’s balance?
What units should I use when calculating unbalance and correction mass?
Results are for informational purposes only and do not constitute professional advice.
