Shrinkable electrical cable core for cryogenic cable

摘要

This invention is a cable core made of two layers of helically wound strips of metal with one layer having a right hand lay and the other layer having a left hand lay. The angle of lay is such that the diameter of the core changes at a faster rate than the length of the strips change with differences in temperature. This increase in the change of the core diameter makes the change correspond more closely to that of a plastic jacket or insulation that surround the core and thus avoids excessive stresses in the insulation as it cools and resulting cracking of the insulation in the case of substantial changes in temperature. The angle of lay of one layer is different from that of the other layer so as to set up restraint conditions that provide stability for the composite construction.