GB849802A - Electrical condenser - Google Patents

Abstract

849,802. Capacitors. BENDIX AVIATION CORPORATION. Dec. 29, 1958 [Jun, 6, 1958], No. 41902/58. Class 37 A capacitance assembly for a jet engine igniter incorporating a voltage doubler is contained in a rectangular housing 12 with mounting brackets 16, closed at the ends by dished caps 14, 15 and is cooled by engine fuel oil entering at aperture 20 and leaving by a further aperture (not shown); the outlet connections 37, 39 being brought out through insulated sealed bushings 19, 29. Capacitance sections 18, 27 respectively comprise plural series laminated foil and paper elements 21 and two similar equal elements 31 of which the latter are connected in series by outlet connection 39 while the outer free end is connected to earthing electrode 40 and the inner free end to outlet connection 37 and to one side of section 18, whose other side is returned to earthing electrode 22. The elements of section 18 are assembled in a stack by layers of insulated fabric 24, 25 retained by tapes 26, 28, 35, while the elements of section 27 are similarly retained in a stack by tape 32. The stacks are superimposed appropriately interconnected, insulated layers 34 are applied to the outer end of section 27, and the whole is bound together by tapes 36 and inserted within the housing 12; there being interpolated at each end a plunger member 41 and plural layers of insulating board 33. Earthed leads are connected, and a frustoconical annular spring 42 is inserted at one end after which the cups 14, 15 are pressed into position under a critical axial pressure and welded. The spring is made of bimetallic sheet stock with the inner component having a higher co-efficient of thermal expansion than the outer, so that the pressure upon the capacitance sections is maintained constant for large variations of temperature, irrespective of the differential expansion of the housing and capacitance elements; thus eliminating capacitance variations. The elements may be wound on a mandrel from superimposed foil and paper and then compressed into flattened form. Specifications 849,801 and 849,854 are referred to.