Abstract: A screen (49) including mesh portions (47 and 48) for a discharge lamp (46) bears a protective coating which inhibits degradation of the screen under lamp operating conditions. The coating does not absorb microwave energy, is transparent or reflective to visible light, and is capable of protecting the screen for at least several thousand hours of operation without substantial oxidation or tarnishing of the screen. The coating remains on the screen at screen temperatures above about 300 degrees C, and the coating does not significantly crack as the screen heats and cools. The coating may include, for example, a solgel deposited single phase or two phase glass.

Abstract: An electrical fuse comprises a fusible ribbon having one or more weak spots along its axial length which is highly resistant to mechanical fatigue caused by cyclic heating and cooling of the fusible ribbon. The weak spot comprises a series of apertures arranged in a curvilinear or angular configuration extending transversely to the axis of the fuse ribbon between the opposite sides thereof. Centers of adjacent apertures of the series are offset from each other with respect to the axis of the fusible ribbon by a distance at least equal to the shortest distance between the geometric center and the peripheral edge of any one of the adjacent apertures such that the cross-sectional area of the weak spot is distributed transversely across the fuse ribbon.

Abstract: A multiple element fuse has a pair of end bells with terminals for connection to spaced apart busbars of an external electrical circuit. A plurality of tube fuses are mechanically fastened and soldered at opposite ends thereof to the end bells. The tube fuses have insulative tubular bodies with metallic ferrules attached at each end. The ferrules which are received in cavities defined in the end bells, include hollow studs for receipt in countersunk holes also formed in the end bells. The studs are flared and/or receive expansion plugs to mechanically attach the tube fuses to the end bells, thereby to preserve the spacing between the end bells even when the fuse is subjected to tensile forces created by the busbars and sufficient heat to melt the solder during fuse clearing.

Abstract: An electrical insulating coating of thermosetting polymeric material for a surge arrester valve element of silicon carbide particles bound together within a ceramic matrix, in which the coating is applied in powder form. Curing of the coating is effected either by a heating cycle following the application of the powder insulating coating, or by preheating of the valve element before application of the powder coating. Alternately, the insulating coating can be applied as a plasma spray, making post-curing unnecessary.