5.6 Flexible Cables
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5.6 Flexible Cables
(1) Life of Flexible Cable
The flexible cable supports 10,000,000 or more operations of bending life with the recommended bending radius
R = 90 mm (3.54 in) under the following test conditions.
• Conditions
1. Repeat moving one end of the cable forward and backward for 320 mm (12.60 in) using the test equip-
ment shown in the following.
2. Connect the lead wires in parallel, and count the number of cable return motion times until a lead wire is
disconnected. Note that one reciprocation is counted as one test.
Note: 1. The life of flexible cable differs largely depending on the amount of mechanical shocks,
mounting to the cable, and fixing methods. The life of flexible cable is limited under the
specified conditions.
2. The life of flexible cable indicates the number of bending times in which lead wires are
electrically conducted and by which no cracks and damages that affects the performance
of cable sheathing are caused. Disconnecting the shield wire is not taken into account.
(2) Wiring Precautions
Even if the recommended bending radius R is followed in the mechanical design, incorrect wiring may cause the
early disconnection. Observe the following precautions when wiring.
(a) Cable Twisting
Straighten the flexible cables wiring.
Twisted cables cause the early disconnection. Check the indication on the cable surface to make sure that the
cable is not twisted.
(b) Fixing Method
Do not fix the moving points of the flexible cable, or stress on the fixed points may cause early disconnec-
tion. Fix the cable at the minimum number of points.
(c) Cable Length
If the cable length is too long, it may result the cable sagging. If the cable length is too short, excessive ten-
sion on the fixed points will cause the early disconnection. Use a flexible cable with the optimum length.
(d) Interference between Cables
Avoid interference between cables.
Interference limits the motion of flexible cable, which causes early disconnection. Keep enough distance
between cables, or provide a partition when wiring.
Bending
radius
R=90 mm
Shifting distance 320 mm (12.60 in)
Fixed end
(3.54 in)
Shifting end
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