Object
The purpose of this test is to determine the ability of an optical fibre cable to withstand repeated flexing in service. This is a specialized test intended for specific types of cable, such as elevator cable or the like.
Apparatus
The test is carried out using the apparatus shown in Figure 12. Any other arrangements shall be specified in the detail specification.
The pulleys shall have a semicircular shaped groove for circular cables and a flat groove for flat cables. The restraining clamps, D, shall be fixed so that the pull is always applied by the weight from which the carriage is moving away. An equivalent apparatus may be used, for example that shown in IEC 60227-2.
Procedure
Unless otherwise specified, the conditions for testing shall be in accordance with standard atmospheric conditions. The sample shall be routed over the pulleys, each end being loaded with a weight. The mass of these weights and the diameters of pulleys A and B (or other) shall be as specified in the
detail specification.
The sample shall be flexed for the number of cycles specified in the detail specification. A cycle is defined as the movement of the carriage away from its starting position to one end of the traverse, followed by movement in the opposite direction to the other end and then back to the starting position. Ensure that the length of the cable is moved over the wheels.
The speed of the carriage movement or the total time for the traverse shall be specified in the detail specification.
The acceleration and deceleration of the carriage shall be limited to avoid additional inertial loads.
Requirements
The acceptance criteria for the test shall be as stated in the detail specification. Typical failure modes include loss of optical continuity, degradation of optical transmittance or physical damage to the cable.