TM 5-3895-374-24-1
ADJUSTING DRIVE BELT TENSION
Proper belt tension and pulley alignment must be
maintained for maximum drive efficiency and belt life The
correct tension exists If a deflection of 1/2" occurs by
placing 10 Ib of force midway between the motor pulley
and the compressor flywheel See Fig 9 This deflection
can be adjusted by the following procedure The pulley
should be carefully aligned with the flywheel, and all
setscrews should be kept tight.
1
Remove the belt guard
2.
Loosen the motor mounting bolts
3
Shift the motor to the point where the correct
deflection exists.
4.
Retighten the motor mounting bolts
5
Check to ensure that the tension remained correct
6
Reinstall the belt guard All moving parts must be
guarded.
NOTE: Drive belt tensioning and pulley alignment are
done at the same time They are discussed
separately for clarity
PULLEY ALIGNMENT
Fig 10 shows three examples of pulley misalignment. To
check pulley alignment, remove the belt guard and place
a straightedge against the compressor flywheel (see Fig
10). Measure and record the distance from the
straightedge to the edge of the drive belt at point A. Then
measure the distance from the straightedge to the edge
of the drive belt again at points B and C. Both distances
should be the same as at point A if B or C are different
from A, there is a misalignment which must be corrected
before the compressor is run. To correct a pulley
misalignment, use the following procedure.
1.
Loosen the motor mounting bolts.
2.
Loosen the setscrew on the motor pulley.
3.
Align the motor pulley with the compressor
flywheel (see Fig 10).
4.
Retighten the motor pulley setscrew.
5.
Adjust the proper belt tension as stated in the
preceding paragraph.
6.
Retighten the motor mounting bolts.
7.
Reinstall the belt guard All moving parts must be
guarded.
THREE EXAMPLES OF PULLEY MISALIGNMENT
(Only one belt is shown, for clarity)
Figure 10. Checking Pulley Alignment
200-2009
(page 3-638)
