Page 95 - Rotating Machinery Pratical Solutions to Unbalance and Misalignment

Field Balancing

example, the unity vector will be constructed at a scale of 10 to 1,
that is 10 divisions on the polar plot will equal 1 unit.
Figure 5-20 illustrates the plot of the unity vector at a scale of
10 to 1.
0
330 30

60
300

270 90

240 120

210 150
180

Figure 5-20. Example (5.4) Plotting the Unit Vector

With the unit vector plotted, the next step is to plot the ab
vector on this new plot using the same scale as used to plot the
unit vector. Next, construct the vector E = ab > UV and measure
its length and angle.

E = .9 units @ 5 degrees.

Step 8. Now the final calculations may be performed.
Ac = (C/E) units @ (C – E) degrees = (5.7/.9) units @ (261
– 5) degrees.
Ac = 6.4 units @ 253 degrees