Handbook Of Shaft Alignment Episode 1 Part 4 ppsx

. The 2
, 4
, and 6
peaks prevailed in the pump bearings.

. Higher multiples of running speed occurred on the pump from 40 to 100 kcpm particularly

during the vertical misalignment runs.

. The twice, fourth, and eighth running speed frequencies are a result of the S-shaped

grid as it traverses from its maximum tilted and pivoted positions twice each revolution

on both the coupling hubs. The third and sixth running speed multiples occur as the metal

grid in the coupling changes its position during each revolution of the shafts. The

Test run #2

M2W

Test run #4

M36W

Test run #5

M65H

Test run #6

M55L

Test run #7

M6W

1 2 3 4 5 6 7 8 9

.01

.02

Inches per second

Frequency (orders of running speed)

.01

.02

Inches per second

Frequency (orders of running speed)

.01

.02

Inches per second

Frequency (orders of running speed)

.01

.02

Inches per second

Frequency (orders of running speed)

10 11 12

1 2 3 4 5 6 7 8 9 10 11 12

1 2 3 4 5 6 7 8 9 10 11 12

1 2 3 4 5 6 7 8 9 10 11 12

1 2 3 4 5 6 7 8 9 10 11 12

.01

.02

Inches per second

Frequency (orders of running speed)

FIGURE 2.23 Inboard MOTOR, vertical direction.

Piotrowski / Shaft Alignment Handbook, Third Edition DK4322_C002 Final Proof page 60 6.10.2006 5:21pm

60 Shaft Alignment Handbook, Third Edition

Test run #2

M2W

Test run #3

M21W

Test run #4

M36W

Test run #5

M65H

Test run #6

M55L

Test run #7

M6W

1 2 3 4 5 6 7 8 9

.01

.02

Inches per second

Frequency (orders of running speed)

.01

.02

Inches per second

Frequency (orders of running speed)

.01

.02

.01

.02

Inches per second

Frequency (orders of running speed)

Inches per second

Frequency (orders of running speed)

.01

.02

Inches per second

Frequency (orders of running speed)

Frequency (orders of running speed)

10 11 12

1 2 3 4 5 6 7 8 9 10 11 12

1 2 3 4 5 6 7 8 9 10 11 12

1 2 3 4 5 6 7 8 9 10 11 12

1 2 3 4 5 6 7 8 9 10 11 12

1 2 3 4 5 6 7 8 9 10 11 12

.01

.02

Inches per second

FIGURE 2.24 Inboard MOTOR, axial direction.

Piotrowski / Shaft Alignment Handbook, Third Edition DK4322_C002 Final Proof page 61 6.10.2006 5:21pm

Detecting Misalignment on Rotating Machinery 61

maximum amount of rotational force occurs when the grid is in the tilted position where

bending occurs across the thickness of the grid member.

. The seven times running speed peak that occurred in the horizontal direction on the

inboard motor bearing during the M55L run and the five times running speed peak that

occurred in the axial direction on the pump are, as yet, not completely understood as to

the source of the forcing mechanism involved. The higher multiples appear to be caused

by overloading the antifriction bearings.

Test run #2

M2W

Test run #4

M36W

Test run #5

M65H

Test run #6

M55L

Test run #7

M6W

1 2 3 4 5 6 7 8 9

.01

.02

Inches per second

Frequency (orders of running speed)

.01

.02

Inches per second

Frequency (orders of running speed)

.01

.02

Inches per second

Frequency (orders of running speed)

.01

.02

Inches per second

Frequency (orders of running speed)

Frequency (orders of running speed)

10 11 12

1 2 3 4 5 6 7 8 9 10 11 12

1 2 3 4 5 6 7 8 9 10 11 12

1 2 3 4 5 6 7 8 9 10 11 12

1 2 3 4 5 6 7 8 9 10 11 12

.01

.02

Inches per second

FIGURE 2.25 Inboard PUMP, horizontal direction.

Piotrowski / Shaft Alignment Handbook, Third Edition DK4322_C002 Final Proof page 62 6.10.2006 5:21pm

62 Shaft Alignment Handbook, Third Edition