User's Manual

Store every balance job for later reference
Use AMS Machinery Manager Data Transfer to transfer the job from the analyzer to the
database. Save jobs to reduce setup time when you need to balance the equipment again.
The necessary setup and dynamic data for one-run balancing are already available, which
reduces the time you spend balancing the equipment.
9.16.3 Measurements that help verify imbalance
Vibration due to imbalance always occurs at the operating frequency, commonly referred
to as 1xRPM. If the vibration occurs at any other frequency or at harmonics of operating
frequency, such as 2xRPM or 3xRPM, imbalance is not the cause. You cannot correct
misalignment, bad bearings, or structural looseness by balancing the equipment.
Spectrum analysis
• A significant vibration magnitude at the 1xRPM peak with very little at harmonics.
• No other unexplained peaks with significant magnitudes appear.
• If available, use zoom or synchronous averaging to verify the exact frequency of the
vibration.
• 1xRPM magnitudes in the horizontal and vertical directions should not be vastly
different (3:1), unless a highly asymmetrical stiffness is in the structure.
• Axial 1xRPM vibration levels should be less than radial levels. This may not be true for
some overhung motors.
Waveform analysis
• The time waveform is very sinusoidal and symmetrical at 1xRPM.
• No truncation or sharp discontinuity appears.
• Beats indicate the presence of closely-spaced frequencies.
Phase data
• Horizontal versus vertical phase readings on the same bearing housing are about 90
degrees apart (±30 degrees).
• The relationship between horizontal readings from end to end is about the same as
the relationship between the vertical probes (±30 degrees).
Additional tests
• Plot coast down data,1xRPM magnitude and phase, as a function of RPM to locate
the magnitude peaks and 180° phase shifts associated with resonances. This data
can help determine where the operating frequency is located relative to any
resonances that may affect the balance procedure.
• Use an impact test to perform a triggered data capture to acquire a spectrum of the
excited structure “ringing down”. This data can identify resonances above or below
running speed.
Balance
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DRAFT