摘要:
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.
摘要:
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.
摘要:
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.
摘要:
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.
摘要:
A method and apparatus for continuously monitoring and measuring the concentration of gases in a gas-containing liquid such as a transformer oil. The method and apparatus employ a passive gas extraction technique which comprises a high performance membrane material to extract dissolved gases from the oil, and an IR-based sensor to detect gases present. The passive gas extractor extracts dissolved gas from the gas-containing liquid, there being a known relationship between the concentration of a constituent gas in the extracted gas and the concentration of the constituent gas remaining dissolved in the gas-containing liquid. The gas sensor senses the concentration of a constituent gas in the extracted gas, in the presence of other constituent gases. The gas sensor comprises a sample chamber which receives the extracted gas, a non-dispersive infrared (IR) absorption sensing system which generates an electrical signal corresponding to the light absorption, at one or more specified IR wavelengths, of the extracted gas in the chamber, and an electrical output comprising the electrical signal generated by the non-dispersive IR absorption sensing system. A processor having receives the electrical signal corresponding to the light absorption, at the one or more specified IR wavelengths, of the extracted gas in the chamber, and computes the concentration of at least one gas constituent present in the extracted gas.
摘要:
An apparatus (10) and a method are described for extracting gas from a liquid containing dissolved gas. The liquid is pumped from an external reservoir (40) of the liquid into a separation cell (14) by a liquid-pumping chamber (11). In separation cell (14) a permselective membrane (17) effects extraction of the dissolved gas from the liquid. A gas-pumping chamber (23) pumps the extracted gas from the permeate chamber (16) of the separation cell (14) to a collection station (27), where the extracted gas can be analyzed, separated into its individual components, or stored, as desired.
摘要:
A sealing system for an acoustic touchscreen includes an elongate gel body between the touchscreen and the bezel of a housing onto which the touchscreen is mounted. The elongate gel body forms a seal around the perimeter of the touch-sensitive area of the touchscreen. A stop element controls and limits the amount of compression of the elongate gel body. The resulting seal is highly effective in protecting the unexposed parts of the touchscreen (i.e., areas other than the touch-sensitive area) from contaminants, especially liquid contaminants, at the cost of an acceptably low loss in acoustic signal strength.