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Balancing to API Standards
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API Standards, in particular API 610 and
API 617, outline a procedure for the determination of
residual unbalance.
The test req uires
the operator to attach a trial mass to the rotor
sequentially in 6 (or 12) equally spaced radial
positions for each plane and record the unbalance
results. The unbalance results must then be plotted in
terms of amplitude versus angular location. The polar
plot is then used to indicate the actual residual
unbalance present on the rotor correction plane.
Comparing the actual residual unbalance to the maximum
allowable residual unbalance determines if the actual
residual unbalance is acceptable.
Anyone familiar with the test will agree that while this
is an effective tool to ensure that an impeller is
within tolerance, it can also add considerable time to
the balancing operation.
Residual Unbalance Software
Residual unbalance software will automatically
calculate the maximum allowable residual unbalance for
the rotor, populate the charts with the unbalance data,
plot the data, and give a pass or fail indication at the
end of the procedure (available o n CAB 803
instrumentation).
The software will save countless
hours in performing this procedure and provide a quick
return on investment. In addition, the software has the
added benefit of reducing human errors associated with
data entry, calculations, and plotting. It also allows
the test data to be stored and transferred
electronically.
After collecting the data for each trial run, the
software will plot the readings, draw a “best fit”
circle, and calculate the circle’s center point.
The software then calculates the residual unbalance by
determining the distance between the center of the
circle and the origin of the polar plot.
The software will compare the actual residual unbalance
to the maximum allowable residual unbalance and provide
a PASS/FAIL indication.
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More about:
Balancing Machines for Pump Impellers
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Instrumentation
Features for Pump Applications
Correction l Balancing
to API Standards |
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