Page 57 - Rotating Machinery Pratical Solutions to Unbalance and Misalignment

Vibration Due to Unbalance

CORRECTING STATIC UNBALANCE
Static Unbalance Weight

Acceptable

Correction Weight

Figure 4-2. Correcting Static Unbalance

In Figure 4-3, two equal weights that equal the weight of the
unbalance are placed equal distances from the unbalance and 180
degrees away. This also causes the rotational center to align with
the center of the shaft.
The correction used in Figure 4-4 results in another type of
unbalance, couple unbalance. Couple unbalance is defined as the
condition of unbalance where the element’s center of rotation
passes through the element’s geometric centerline at the element’s
center of gravity.

CORRECTING STATIC UNBALANCE

Static Unbalance

Acceptable

Correction Weights

Figure 4-3. Correcting Static Unbalance with Two Weights