Measuring rotation unbalance of a drilling machine

 

This application shows how to measure the unbalance vibration of a drilling machine.
As the damage or breakage of the rotating shaft caused by unbalance vibration is very dangerous, drilling machine should be maintained periodically.
Use the HT-5500 digital hand tachometer as a rotation detector to select the rotation pulse of the rotation axis and input it to the external sample pulse of the Data Station DS-3000.
To see the details of the unbalance, rotation primary vibration should be focused on. Start up the FFT analyzer in the tracking mode and compare the primary vibration value with the rotation pulse as the external sample clock. In addition, the acceleration signal is integrated once and measurement is performed as the vibration speed.

 

イラスト(掘削機の回転アンバランス計測 )

 

 

System configuration

 

  Model name Product name Remark

1

DS-3000 series Data Station  

2

HT-5500 Handheld Digital Tachometer  

3

NP-3000 series Accelerometer  


Example of analysis data

 

画面データ(回転アンバランス)

 

The figure above shows data when rotation unbalance vibration is occurred in the drilling machine. If imbalance occurs, vibration of the primary rotation will increase. In this example, initial value is 5 mm/s of vibration, but the value after rotation unbalance occurred is 16.3 times, increased to 81.917 mm/s.
Generally, as a guide, at 1000 Hz or less of speed or displacement signal, roughly 3 times the initial value (good state) is attention level and 9 times or more as the dangerous level (see ISO 2372).

 

For successful

  • • Tracking analysis for synchronizing rotation speed is effective for analysis of rotating equipment
  • • In the unbalanced state, vibration component of the primary rotation is important.
  • • The low frequency such as the primary rotation is analyzed as vibration speed obtained by integrating the acceleration   signal once, or the vibration displacement obtained by integrating twice.
  • • Install the accelerometer at the position where the vibration value is large.

 


Revised:2019/2/27

 



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