Manfred Weber
Metra Mess- und Frequenztechnik in Radebeul e.K.
PC Vibration Measurement System VibroMetra

Mass change

Mass change is carried out before vibration measurement. The changes made need to be entered into VM-BAL. The software can also make suggestions for the test mass.
Mass change

Mass change selected

1. Mass change selected
After finishing the initial run the first test run is started with a mass change.

Side display

2. Side display
This section gives information about the next step and quick access to the relevant settings.

Adding / removing mass

3. Adding / removing mass
Select the intended way of changing mass.

Amount of test mass

4. Amount of test mass
Enter the mass you have removed or added.

Angle of test mass

5. Angle of test mass
Enter the angle position where you have added or removed mass. Angle steps will be offered for balancing at fixed positions.
All subsequently displayed angles will refer to this position. Preferably the test mass should be at the same position as the zero angle of the reflex mark because
  • There is a visible mark at this angle position.
  • The angles of vibration measurement, unbalance display and mass changes refer to the same coordinate system.

Radius of test mass

6. Radius of test mass
The test mass may have a different attachment radius. This reflects the fact that some machines provide already during production positions for arranging test masses. As default value the balancing radius is indicated.

Mass after measurement

7. Mass after measurement
Normally the test mass will be removed after the test run. In some situations it may be desired to leave the test mass at the rotor.

Accept suggestion

8. Accept suggestion
Click this button to transfer the suggested mass and angle into the input fields.


9. Suggestion
The test mass is often chosen arbitrarily, sometimes based on experience. The purpose of adding or removing some mass is changing the dynamical behavior of the rotor to a certain degree. Extreme vibration needs to be avoided, too.
VM-BAL can make a suggestion for the test mass under the following preconditions:
  • Balancing radius and rotor mass have been entered.
  • The sensors for vibration and zero angle are in one line.
  • The recommended angle uses the reflex mark as reference.
  • The suggestion is only applicable for adding mass.

Confirm settings

10. Confirm settings
Click this button to confirm your changes and proceed to vibration measurement.
The confirm button turns into an edit button. You can return to the mass edit menu as long as vibration measurement has not been started yet.