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Page Title:
Tes Method No. 28 - Boom Extension and Retraction Speeds - Extension Cylinder Cavitation |
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| MIL-C-53057(ME)
APPENDIX
TEST METHOD NO. 28
BOOM EXTENSION AND RETRACTION SPEEDS - EXTENSION
CYLINDER CAVITATION - SIMULTANEOUS HOIST AND EXTENSION
1. TEST APPARATUS:
a. Linear measurement equipment.
b. Stopwatch.
c. Hydraulic pressure gages capable of reading below atmospheric
pressure.
2. TEST PROCEDURE:
a. Boom extension and retraction speeds.
(1) Record time to extend the boom at a 60 degree boom angle
from the retracted boom position to full boom extension.
Note whether speed remains constant throughout extension.
(2) Record time to retract the boom from full boom extension
at a 60 degree boom angle at maximum speed (full open
valve) to within 10 feet of full boom retraction. Note
whether speed remains constant throughout retraction.
(3) Repeat steps a and b a minimum of 5 times.
(4) Compute extension and retraction speeds and use the
fastest rate obtained from each as the established speeds.
b. Extension cylinder cavitation.
(1) Install the pressure gages to read hydraulic pressure on
both ends of the boom extension cylinder.
(2) Raise the boon to a 60 degree boom angle with the boom
fully retracted.
(3) With the engine at low idle speed, fully extend and
retract the boom maintaining a 60 degree boom angle, not
less than 10 times. Boom retraction shall be accomplished
with control valve wide open 5 times and "feathered" 5
times. Observe and record any evidence of cavitation in
the extension cylinder or loss of operator control. Record
pressure readings. Note: Pressure readings are not
required for determining extension cylinder cavitation for
quality conformance testing purpose.
(4) With the engine at low idle speed, fully extend and
retract the boom at minimum boom angle (maximum angle
below the horizontal), not less than 10 times. Boom
extension shall be accomplished with control valve wide
open 5 times and feathered 5 times. Observe and record any
evidence of cavitation in the extension cylinder or loss
of operator control.
93
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