Nonlinear resistance stack for HV protection - has discs held between end contacts and enclosed by heat shrunk film

摘要

The excess voltage protection device for high voltages uses a stack of non-linear resistances (4) shaped as discs. The stack is held together by a foil (1) which is hot shrunk around them also acting as an insulation layer. The foil may be polyethylene or fluorine plastics sheet. The stack, which also includes a contact disc (2,3) at each end, is supported by channel with a plate at each end, with a screw passing through a tapped hole in each plate to apply pressure to the ends of the stack while the foil is being heat shrunk around it.