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(16)
Calculate the distance between the imbalance correction point and the first indexed point of the vector with the highest residual vibration amplitude as follows:
Distance = (Corresponding residual vibration) x (Sensitivity at 1st point)
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(17)
On the vector above, make a plot on the polar graph of the balancing weight .W2 at the distance calculated from the first point.
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(18)
Read the value and angle of the balancing weight .W2.
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(19)
Calculate the residual vibration as follows:
(a)
On a polar graph paper (Fig. 505), make a scale from the origin (center of the graph) to the outer perimeter in units of g-cm.
(b)
Make a plot of the 6 indexed points (the balancing weights at their calculated angles).
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(c)
On the same graph, make a plot of the balancing weight .W2 you calculated above.
(d)
Calculate the residual vibration as follows: 1) Measure the distance (in g-cm) between each indexed point and the balancing weight .W2.
2) Divide this distance by the sensitivity at the indexed point:
Residual vibration at A = Length from A to .W2 --------------------Sensitivity at A
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(20) Optimize the residual vibration level as follows:
NOTE:____After the calculation, some of the residual vibration can be too high. If this occurs, you must make the balancing weight .W2 better to make all the residual vibration amplitudes satisfactory.
(a)
Around each of the changed points, draw a circle whose radius (g-cm) is equivalent to the sensitivity at that point multiplied by the maximum satisfactory amplitude.
R (g-cm) = Sensitivity (g-cm) x Vibration amplitude (mils) ------------------mils
(b)
Use the same formula given above, draw a circle around each of the other points and slowly increase the initial residual vibration until the area that is common to the intersecting circles is found.
NOTE: This point will be the location of the improved
____
balancing weight .W2.
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(c) Read the value of the improved .W2 and its phase angle A2.
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(21) On a polar graph, find the final balancing weight W4 as follows:
(a) Vectorially add the balancing weight W1 (which was installed for the first test run) and .W2 (that you calculated above).
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(22)
Find the balancing weight that corresponds to the original balancing screw W0 and its phase angle A0.
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(23)
On a polar graph, make a plot of the vector W0 at the angle A0.
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(24)
From the end of the vector W0, make a plot of the vector W4 at angle A4 you found above.
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(25)
To draw the resultant vector, draw a line that connects the origin of the graph (start of vector W0) to the end of vector W4.
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(26)
Measure the resultant vector (weight WS) and the phase angle (AS).
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(27)
Find the correct balancing screws for the weight WS as follows:
