FAQ: MicroVib II Balancing: Balance Readings
 

 

When characterizing a balance problem, your balancer will produce three different pieces of information to describe your machine's balance. These three readings are Tach Speed, Vibration Level and Phase Angle.

Each of the three is needed in order to properly determine the balance state of the machine under test.

These three readings are unaffected by the MicroVib II's current state of "learning".

  Tach Speed (RPM)
 
The tach speed (usually indicated in RPM) is produced by either a Photo-Tach or Magnetic Pickup. It indicates the actual speed of the rotating portion of the machine being balanced. In order to provide an effective balance, the machine should be operated in the normal operational speed range in order that the other two parameters (Vibration Level and Phase Angle) have meaning.

The tach speed is used by the operator to determine that the machine is operating in the proper state to collect balance readings.
 
H Vibration Level (IN/S)
 
This is the amount of vibration or magnitude of the machine which is produced by unbalance. This value generally corresponds to how far the machine is out of balance. The higher the vibration level, the more adjustment must be made to balance the machine. The vibration level is generally described in IN/S Peak Velocity.
 
The vibration level is used by the MicroVib II to determine how much adjustment (generally weight) is needed to balance.
 
  Phase Angle (Degrees)
 
The phase angle describes the number of degrees of machine rotation between two events.
  • The first event is the heavy side of the machine forcing the accelerometer to move in a positive direction.
  • The second event is the tach signal occurrence when the photo-tach detects the passage of reflective tape.
The phase angle is used by the MicroVib II to determine where the adjustment needs to be installed on the rotating portion of the machine.
 
  How Are These Readings Used?
  • The operator monitors the Tach Speed to determine that the machine is in the proper operating state to collect balance readings.
  • The MicroVib II produces Vibration Level and Phase Angle readings.
  • The Vibration Level is used to compute how much adjustment (weight) needs to be made.
  • The Phase Angle is used to compute where the adjustment needs to be made.

For more information about MicroVib II Proposed Solutions, click here.
 

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