How to Minimize the Effects of Coupling Backlash when Measuring Misalignment.

Certain types of flexible couplings are designed to have looseness creating coupling backlash.  Even when installed correctly!  Looseness from coupling backlash, if not controlled, will have a negative effect on measurement quality by increasing measurement error and the amount of time it takes to do a precision shaft alignment.  So, how can coupling backlash be lessened or eliminated?  Check out the simple procedure below:

In the direction of rotation, engage the coupling from the motor side and move the sensors to 9 o’clock.  Take the first measurement. 

Then move the sensors to 11 o’clock keeping the coupling engaged from the motor side.  Take the second measurement. 

Then rotate the sensors to 3 o’clock to take the third measurement.  When the sensors pass 12 o’clock, switch the engagement to the pump (driven) side.  This will keep the coupling engaged in the same direction throughout the measurement process. 

By using this procedure you will minimize the effects of coupling backlash and increase your measurement accuracy!  You will end up getting a precision shaft alignment done faster with less moves.