MARMON VITALink MC, Руководство по установке

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• Pulling in the proper direction. Where practi-
cal, a cable pull should begin nearest the end
having the greater degrees of bends and exit
the end having the least degrees of bends.
Also, where vertical sections are encountered,
a downward pull is preferred.
• The number and degrees of bends the cable
is pulled around under tension should be min-
imized. This may be accomplished in tray
installations by setting up at a bend and
pulling the cable straight past any bends at
the far end of the installation and feeding
additional cable off the reel at the bend. The
cable may then be hand fed around the
bend(s) at either end.
• Cable pull tension should be minimized by
turning the reel and feeding the cable into the
raceway or tray.
An experienced cable pulling observer should
be stationed at the pulling end and be in contact
(visually, by radio or by phone) with the other
members of the crew. A suitable guide device
should be used to protect and guide the cable
from the cable reel into the raceway or tray. The
radius of the feeder device should not be less
than the minimum bending radius of the cable.
Cables exiting the raceway or tray should be
protected by similar means.
Pull Tension Monitoring
Cable tension should be limited to less than the
maximum allowable pulling tension, to help
ensure that the installation process does not
damage the cable. This may be accomplished
by one of the following two methods:
1. Limiting the amount of tension available by
use of a properly sized breakaway link.
• Breakaway links should be sized to be less
than the maximum allowable pulling tension.
• If the maximum allowable tension is exces-
sive, then a breakaway link should not be
used unless an estimated tension calcula-
tion is performed which indicates the ten-
sion to be well within allowable limits.
2. Monitoring the actual tension applied using a
tension measuring device.
• The pull force should be monitored for all
high tension pulls (such as mechanical
pulls, tuggers, etc.).
• It is highly recommended that estimated
tension calculations be performed for all
high tension pulls.
If possible, a direct reading tension measuring
device should be used. When this is not possible,
and a dynamometer is used that is not placed in
direct line with the cable pull, the reading must be
multiplied by the appropriate multiplying factor
from Table 10 to obtain the true pulling tension
(see Figure 8). When the angle falls between two
tabulated values, the multiplying factor should be
assumed to be the value for the larger angle. If
the angle is greater than 120 degrees please
contact the RSCC Engineering Depart ment for
assistance.
Angle (Degrees) Multiplying Factor
0 0.5
60 0.6
90 0.7
100 0.8
110 0.9
120 1
Table 10. Multiplying Factors For Use With
Dynamometer Readings