Section  12  —  Balancing  Walkthrough 
235 
Step 2 — Take Initial Reading 
 
To  take  an  initial  reading: 
1.  Stop  the  machine. 
2.  Attach  the  sensor  to  the  bearing  housing  closest  to  the  rotor.   
 
TIP: For best results, attach the sensor in the radial direction in 
which the machine is most flexible (and vibrates the most). 
 
For  dual  plane  balancing,  attach  a  sensor  to  each  of  the 
bearings  supporting  the  rotor.  It  is  NOT  important  how  the 
sensors  are  paired  or  which  sensor  is  attached  to  which 
end. 
 
3.  Set  up  the  tachometer  (see  Setting  up  the  Tachometer. 
4.  Start  the  machine  >  Let  the  rotor  settle  to  its  normal  operating 
speed.   
 
NOTE: Because the vibration level depends on the speed of the 
rotor, it is important to take all readings while the rotor is 
operating at its normal speed. 
 
5.  Press    from  the  Balance  Setup  menu  to  take  the  initial  reading 
—The  initial  reading  measures  the  out  of  balance  level  of  the  rotor. 
6.  After  a  few  seconds,  the  instrument  displays  the  speed  of  the  rotor 
in  RPM  and  Hz,  the  vibration  level  due  to  the  imbalance  (i.e. 
amplitude  at  1X  the  rotor  speed),  and  the  phase  angle  of  the 
vibration. 
 
For  dual  plane  balancing,  two  sets  of  values  display. 
 
7.  Wait  for  the  readings  to  stabilize  >  Press  .