©
2000 Schneider Electric All Rights Reserved
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4/00
XY2 Cable Pull
Application Information
Cornering
The operating cable should be installed so that
the cable run is straight, b ut this cable can also be
routed around corners using pulleys. If the cable
deviates from a straight line, pulleys
must
be
used. The effects of friction could be more
noticeable if the cable is not installed correctly and
with a minimum of friction.
• DO NOT allow the cable to turn corners or
change direction using only cable supports.
• A pulley
must
be used when routing cable
around corners, regardless of the angle. Use a
pulley whenever direction is changed even
slightly. The pulley must have freedom of
movement on its mounting to maintain the self-
alignment of the cable.
•If a fix ed pulley is used, a cable support should
be positioned within 4 inches (10 cm) of both
sides of the pulley.
•The total sum of the angles for the cable bends
or turns should be no more than 180°.
i.e.: qty of two 90-degree angle turns is
acceptable.
i.e.: qty of three 60-degree angle turns is
acceptable.
i.e.: qty of three 90-degree angle turns is not
acceptable.
Temperature
Temperature variations in the area where the
cable pull switch is installed can affect the
adjustment of the switch. The cable expands
(becomes longer) when temperature increases,
and contracts (shrinks) when temperature
decreases. Wide temperature variations should
be avoided where possible. If temperature
variations are significant, the adjustment of the
cable and switch must be checked at regular
intervals. If the switch is not adjusted properly
during installation, temperature variations could
affect cable length and trip the switch without
operator intervention. If this occurs, the switch
needs to be readjusted.
Temperature v ariances can come from any of the
following:
•Seasonal temperature changes in non-climate
controlled areas.
• Freezers and refrigeration equipment which
are cold during production but are brought to
room temperature for cleaning.
• Equipment that is used to heat treat or cook
material during production but is brought to
room temperature for cleaning.
• Equipment which is at room temperature (or
lower temperatures) for production but is
cleaned with hot water or steam.
• Equipment placed near windows and large
glass areas: sunlight could cause an
expansion of the cable where an overcast da y
may cause a contraction of the cable.
Note: Routing the cable through both hot and cold
production areas with the same cable could
require more frequent adjustment and
may
not
allow proper adjustment throughout the
production cycle. Example: A cable pull switch on
a production line where the product is cooked and
then flash frozen in a short distance. Some
sections of the cable could be v ery hot, and other
sections very cold, and other sections at room
temperature. Temperature variations in any of
these areas could aff ect the ov er all adjustment of
the cable. Where such variations occur, we
recommend the use of multiple cable pulls.
General Guidelines
• Be sure the cable remains accessible and
visible to the operators for its entire length.
• The switch, cable supports, and other
hardware must be rigidly mounted on the
machine or application. If these mountings are
not secure and rigid, the tension on the cable
could be changed and the switch will trip.
Mounting points must not move when the cable
is pulled.
• Supports are not to be placed on moveable
parts of the application.
• Cable lengths used must not be in excess of
maximum lengths listed f or the particular cable
pull switch.
• The turnbuckle allows for the proper
adjustment of the switch, and must be mounted
close to the switch to ease and simplify
adjustment of the system.
• The turnbuckle locknuts should be tightened
securely.
• The first cable support should be within 4
inches (10 cm) of the switch.
• The sheath around the end of the cable must
be removed when inserted into the cable
clamps to assure metal to metal contact.
Failure to remove sheathing could cause
slipping of the cable, reducing the tension on
the cable, and switches may not perform to
published specifications.
Courtesy of Steven Engineering, Inc. ! 230 Ryan Way, South San Francisco, CA 94080-6370 ! Main Office: (650) 588-9200 ! Outside Local Area: (800) 258-9200 ! www.stevenengineering.com