Selecting the right cable for an application starts with a few fundamental parameters. First, determine the application type. In a motion application, will the cable be stationary or will it be moving? If the latter, is the motion mainly flexing or is there torsional motion involved? Or does the application call for both flexing and torsion? Different applications have specifically designed cables for that application.
If there is bending or motion involved, the bend radius has to be specified. The bend radius ultimately depends on the gauge of the wire and the kind of conductors used in the cable. The cable size includes the gauge of the wire, which is dependent on the current requirements as well, and the number of conductors needed by the application. As a general rule, the finer the conductor gauge the smaller the allowable bend radius. Flat cables with PTFE jackets can have a larger bend radius than cables with silicone jacketing, given that each cable contains the same conductors.
For cabling used in flexing applications, the two key factors are the wire conductors and the cable jacket. With continuous flexing, conductors containing multiple strands of fine-gauge wire generally last the longest.
Cable materials are also important. Specifically, this refers to the insulation and jacketing material. There is a wide array of selections depending, once again, on the application needs, and can include PVC and halogen-free to Neoprene, rubber, silicone and other materials. Also, do the cables require electrical shielding? In addition, consider any approvals that the cables may need to meet such as UL, CSA, CE, RoHS or others.
The environmental conditions in which the cable will operate are also important in the selection process. Chief environmental factors include exposure to harsh conditions such as temperature and humidity, and resistance to environmental contaminants such as any oil or corrosive materials.
For instance, what is the operating temperature for the application; will the cables be in low-temperature (freezing and below freezing) or high-temperature environments? Also, will the cables need to be oil resistant? In this case, there are cables that provide minimal protection which may be sufficient for low-level exposure and cables that provide full immersion protection over a period of days. Lastly, consider flame resistance. Options can range from minimal protection to higher levels of protection as the application calls for them.
Filed Under: Cables + cable management, Motion Control Tips
