Page 93 - Rotating Machinery Pratical Solutions to Unbalance and Misalignment

Field Balancing

Fb = (b × F0) mils @ (b + F0) degrees = (.5 × 5.4) mils @ (160
+ 215) degrees.

Fb = 2.7 mils @ 15 degrees.

Note: The sum of the degrees for Fb was greater than 360, so the
result had 360 subtracted from it, 372 – 360 = 12. At times, the
results can provide a negative degree. This is corrected by adding
360. Assume a reading of –45 degrees was obtained. The final
answer would be –45 + 360 = 215 degrees.

Step 5. Once again, some vectors will need to be constructed.
Starting with a new polar graph, construct the following vectors:
Fb, N0, Na, F0.

Now the vectors C = N0 > Fb and D = F0 > Na can be plotted
and measured for their length and associated angles.

0
330 30

60
300

270 90

240 120

210 150
180

Figure 5-18. Example (5.4) Data Plot