Interactive tool. Evaluates the residual unbalance verification test for one correction plane. Enter 6, 8, or 12 machine readings as unbalance vectors or as correction masses and angles; it returns the verified residual, the calibration scale check, the reading scatter, and a polar plot.
This calculator performs the residual unbalance verification test for one correction plane. Enter the test mass and radius, the machine's reading at each of 6, 8, or 12 test positions, as an unbalance vector or as a correction mass and angle, and the balance tolerance; it returns the verified residual, the calibration scale check, the reading scatter, a to-scale polar plot of the test, the comparison against the machine's reported residual, and an explanation in prose of what each result means — in SI or US units (oz·in or g·in), with a printable record. Companion tool to Low Speed Balancing Procedure. Part of the balancing series.
The calculator's results have been compared with those of a separately written program in 18,000 randomized cases, and every displayed value agreed with it to the last digit. In simulated tests, the calculator also recovered a known residual in magnitude and phase, including from readings distorted by a calibration scale error.
Sample output
The calculator's output for the worked example in Low Speed Balancing Procedure: a 1 g test mass at 178 mm, eight test positions, a balance tolerance of 40 g·mm, and a machine-reported residual of 30 g·mm at 116°.
Result
Value
Test unbalance Ut (g·mm)
178
Circle center Rc (g·mm)
28.48 ∠ 119°
Circle radius Rr (g·mm)
183
Verified residual Ures (g·mm)
27.7 ∠ 119°
Tolerance comparison (27.7 vs 40 g·mm)
PASS
Urep vs Ures, magnitude difference
8.29 %
Urep vs Ures, angle difference
-2.98°
Calibration scale error
+2.79 %
Unbalance reading scatter
-0.978 % to +0.906 %
The polar plot and the printed record for the same example. Click either image to enlarge it.
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