Section 4: Balancing Rotors
This section describes the procedure for performing balancing
operations with your instrument.
You will learn to:
• Understand the balancing process
• Select appropriate balancing settings
• Set up a balancing job
• Manually enter balancing values
• Use the instrument's suggested balance weight calculations
Methods for Balancing Rotors
The instrument can balance rotors that are rigid and which do not
flex significantly at their operating speeds.
An imbalanced rotor is one that has an uneven mass distribution that
causes the rotor to vibrate when it is rotated. Balancing a rotor
requires correcting the uneven mass distribution by adding or
removing weight to/from precisely calculated positions on the rotor.
A rigid rotor can be balanced in one plane or two planes i.e. any
uneven mass distribution in the rotor can be corrected by
adding/removing weights to/from one or two selected cross-sectional
planes on the rotor.
For single plane balancing the mid plane of the rotor is usually used
as the balancing plane. For dual plane balancing, usually the planes
at the extreme ends of the rotor are used; however, other planes on
the rotor can be used also.
Since the effect of a rotating weight (i.e. the centrifugal force)
increases with the radial distance of the weight, it is common to add
weight to, or remove weight from, the rim of the rotor rather than a
position close to the centre of rotation. Making weight adjustments at
the largest possible radial distance minimizes the amount of weight
that needs to be added to or removed from the rotor.