Abstract: A disk drive includes a power driver chip, a microprocessor chip and a single reset line coupled to respective pins of the power driver and the microprocessor chip. The power driver chip includes a control circuit for inhibiting the power driver chip from de-asserting a reset signal on a reset line while the microprocessor chip is asserting the reset signal on the reset line.

Abstract: A surge arrester (1) includes varistor elements (2) forming a stack (3) and having opposed end surfaces (4a, 4b). The varistor stack is electrically connected via the opposed end surfaces to end terminals (7a, 7b) having circumferential ridges (32a, 32b), which, in the event of failure of the varistor elements, are designed to relocate the resulting arc and direct it in a manner which reduces or minimizes damage to the surge arrester. The ridges serve as damage-tolerant sacrificial rooting points for an arc in the event of varistor element failure by presenting a substantial metal mass for the arc to erode away.

Abstract: A surge arrester has end terminals having circumferential ridges, which, in the event of failure of varistor elements of the surge arrester, are designed to relocate the resulting arc and direct it in a manner which reduces or minimizes damage to the surge arrester. Grooves lead from the inner surface of the terminals to the ridges, to facilitate arc relocation.

Abstract: A composite article is formed from yarn, comprising high strength fibres and fusible blocking material, and outer fusible material. The yarn is formed into its required shape and placed in a mould. The outer fusible material is introduced into the mould and its temperature is raised so as to melt the lower-melt temperature blocking fibres of the yarn. Under the action of temperature and pressure in the mould, the blocking material fuses so as to fill any interstices between the strength fibres, and the yarn is enclosed within the outer fusible material. The method is useful for forming electrical insulators of high strength glass fibre in the form of a loop (4) blocked against flow of moisture by polypropylene and enclosed within non-tracking polyethylene electrically insulating material (6).

Abstract: A surge arrester includes varistor elements forming a stack and having opposed end surfaces. The varistor stack is electrically connected via the opposed end surfaces to end terminals having circumferential ridges, which, in the event of failure of the varistor elements, are designed to relocate the resulting arc and direct it in a manner which reduces or minimizes damage to the surge attester. The ridges serve as damage-tolerant sacrificial rooting points for an arc in the event of varistor element failure by presenting a substantial metal mass for the arc to erode away.

Abstract: A surge arrester has a single varistor element or a stack of varistor elements held between two end terminals by a plurality of elongate strength members disposed therearound. The ends of the strength members are inserted into recesses in the end terminals. Crimping of the end terminals distorts the recesses sufficiently to hold the strength members firmly therewithin, but without shearing and crushing (or otherwise damaging) the strength members.

Abstract: A sealed vented surge arrester and method of manufacture is described wherein the valve elements are held under compressive loading while strength members including a moisture sealing void filling compound are pressed fit from the sides of the unit with a shed applied over it. The design achieves all the desirable features of tubular strength members with an ease of manufacture from utilizing half-shell or more members which can be applied from the sides along the longitudinal axis of the valve elements during manufacture to provide better void filling between the structural members and the valve elements.

Abstract: A double-walled article in the form of a tube having a small volume filling of a friction-reducing liquid or solid between its two walls. The article is able to revolve over a substrate by relative sliding motion between its two walls, to provide environmental or electrical protection.

Abstract: A double-walled article in the form of a tube having a small volume filling of a friction-reducing liquid or solid between its two walls. The article is able to revolve over a substrate by relative sliding motion between its two walls, to provide environmental or electrical protection.