6) Measure the length of R1.
7) Write the length of R1 on the worksheet (Fig. 527).
8) Measure clockwise the angle (X) from the 0° radial line to
vector R1. 9) Write the angle (X) on the worksheet (Fig. 527). 10) Calculate the balance weight W6 that you will add.
W6 = 1040 (weight of three P05 screws) x U0
------------------------------------------R1
11) Write the balance weight, W6, on the worksheet (Fig. 527). 12) Calculate the sensitivity as follows.
S = 1040
----R1
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(f) (g) (h) 13) Write the sensitivity, S, on the worksheet (Fig. 527).Make a selection of applicable graduations, in g-cm, on a polar graph (Fig. 505) that will include all of the points (W6) that you calculated.On the graph, put the balance weights W6 at angles X for the six points which have labels A thru F.Make a line (vector) between each point, as it is shown on Fig. 506.
EXAMPLE:_______ A-B, A-C, B-C, ...
(i) Use the data from Fig. 527 to write the sensitivity of each index point (P1 and P2) of each vector on Fig. 506.
NOTE:____ An example for AB is: sensitivity of A (P1) = SP1, sensitivity of B (P2) = SP2.
(j) (k) Add the two sensitivities for each vector (SP1 + SP2).Calculate the amplitude (U) of each vector and write it on Fig. 506:
U = Length of Vector P1-P2 ------------------------------------------------
Sensitivity of P1 (SP1) + Sensitivity of P2 (SP2)
(l) Use the vector with the maximum amplitude to calculate the distance from the start of the first vector (P1), to the balance point W7.
NOTE:____ The distance from P1, dP1 = U x (SP1)
(m) (n) 1) Write the value, dP1, on the worksheet (Fig. 506).Start at point P1 and go along the vector P1-P2 on Fig. 505 to put the calculated length, dP1, on the graph.Make a vector, with a label W7, from the origin (the center of the graph) to the end of dP1 on P1-P2.
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(o) Measure, and make a record of the length (the imbalance weight (g-cm)) and the phase angle (A7) of W7.
S 975-073-C00
(19) Use the one-shot plot porcedure to do the selection and installation of the balance screws.
(a) Make sure you replace the three P05 test weights with
lubricated P07 screws.
S 715-074-C00
(20)
Obey the applicable WARNING and CAUTION as you do an engine run.
S 755-075-C00
(21)
See if the vibration levels of the No. 1 bearing (or FFCCV) are not more than 3.5 mils DA and the levels of the TRF are not more than
4.0 mils DA.
(a)
If the vibration levels are not more than the limits, the trim balance procedure is completed. 1) Do this subsequent task: Put the Airplane Back to Its
Usual Condition.
(b)
If the imbalance continues to be more than the limits, do troubleshooting, as follows, to make sure the indications are correct: 1) Examine all of the data from the engine runs to make sure
_________ the calculations were done correctly.
____________________________________
2) Examine the condition of all connectors.
NOTE: Dirty or wet connectors can cause incorrect
____
vibration indications.
3) Do a check for accelerometer mounting brackets that are loose. 中国航空网 www.aero.cn 航空翻译 www.aviation.cn 本文链接地址：737-300 400 500 AMM 飞机维护手册 ENGINE 发动机 1(115)
