Even though we added weight, the machine shows excessive unbalance and angle shift. What's wrong?

If the machine still exhibits a high degree of unbalance and angle shift despite the added weight, this usually indicates that the correction was performed at the correct location but at the wrong level. Unbalance is a vector quantity that not only has a magnitude but also a direction. In other words, determining the location of the weight to correct rotor imbalance is as critical as determining the amount of weight needed. If you add the correct amount of weight at a point even a few degrees off the calculated angle, you won't completely correct the rotor's imbalance. Instead, you'll add new imbalance to the existing one. This will cause the machine to recalculate the amount and angle of unbalance, resulting in a result that differs from the initial measurement.

To resolve this issue, you should proceed based on the new measurement taken by the machine after the initial balancing operation. MBS Balance machines can guide you in such cases by precisely determining the remaining unbalance and the new angle. Based on this new data, you can eliminate the remaining imbalance by making a second adjustment at the correct amount and location. Remember, balancing is not a one-time intervention, but rather a gradual process that must be repeated until the correct result is achieved. The correct positioning of the added weight is key to successful balancing, and in these cases, the best approach is to act without haste and rely on the machine's new data.

This situation must be solved vectorially: the measured initial unbalance is one vector and the weight you add is a second vector; the residual unbalance is the resultant of these two. A large shift in the angle indicates that your correction vector is angularly deviated relative to the target; the amount remaining higher than expected indicates that the weight was placed at the wrong radius or was not fully secured. If the weight is placed at a radius different from the calculated one, its effect changes proportionally.

Points to Check

• That the angle reference (0 degrees) is correctly marked on the part
• That the weight is placed at the calculated radius and in the correct plane
• That the fixture and connections are not loose
• The machine's calibration linearity and plane entries

MBS Balance machines recalculate the residual vector after correction and directly show the amount and angle of the next step; with this guidance, most rotors reach tolerance in one or two iterations.