Abstract: This present application concerns a method for preventing an electrical grid from a failure in case of a temporary overvoltage. A method comprising: a) providing an electrical grid line, a surge arrester and a disconnector device with a disconnector unit; b) connecting the surge arrester at one terminal to the electrical grid line; c) connecting the surge arrester at its other terminal to a second terminal of the disconnector device; d) connecting a first terminal of the disconnector device to ground potential; e) interrupting the electrical connection in between the electrical grid line and the ground potential in case of a temporary overvoltage; f) protecting the surge arrester from failure due to a thermal overload caused by the temporary overvoltages by operating the disconnector device before the surge arrester fails due to a thermal overload of the surge arrester.

Abstract: An electrical protection component with a short-circuiting device includes a gas-filled surge arrester that includes at least two electrodes. Preferably, one electrode in each case is arranged at the ends of the surge arrester. The electrical protection component has a thermal short-circuiting device, wherein the thermal short-circuiting device includes a clip having at least two sections. At least a first section of the clip is attached to the surge arrester by snap action. At least a second section of the clip at least partly surrounds the first section and is spaced apart from the first section by means of a fusible element. The second section has a short-circuiting link at an end. The short-circuiting link electrically connects the electrodes of the surge arrester to one another in the case where the fusible element melts.

Abstract: A structure for installing a lightning arrester between the cross arm mounted to the upper end of an electric pole and a power line is disclosed. A dead end clamp, the lightning arrester and an insulation reinforcing insulator are connected in series, an end of the insulation reinforcing insulator is connected to the cross arm by a shackle, a disconnector is connected to the voltage outlet portion of the lightning arrester, a grounding wire for diverting abnormal voltage to the ground is connected to the disconnector, and an insulation cover surrounds the dead end clamp and the voltage inlet portion of the lightning arrester.

Abstract: A thermal actuator includes a thermal detector, an actuator unit and a connecting circuit for electrically connecting the thermal detector in parallel with the actuator unit. The thermal detector includes a first contact member and a second contact member normally remained in contact with the first contact member. However, the second contact member will bend to uncontact with the first contact member when an overheated or over-cold temperature occurred around the thermal detector, so that the current normally flowing through the thermal detector will flow to the actuator unit too. Therefore, a heat wire wrapped around an actuating piece of the actuator unit generates heat to increase the temperature around the actuating piece. When the temperature around the actuating piece increases to a predetermined extent, the actuating piece bends so as to provide an actuating action.

Abstract: Protection of a cable, its termination and other apparatus from lightning strikes on an overhead line is provided by housing a surge arrestor and a cable termination, which are connected in parallel in a common housing, but as separate components not sharing the same axial line. With this configuration, minimal lead length is provided without sacrificing serviceability.

Abstract: A low voltage valve type arrester device for connection between a domestic electric supply line and earth includes a varistor, a switching device and an encapsulated gas discharge voltage arrester connected in series. The switching device includes two switch members connected together by a solder connection and biased apart by a spring. A fusible link is connected to the two switch members in parallel with the solder connection. When a voltage surge occurs, current flows through the arrester to earth. If the surge is large enough to render the gas discharge arrester continuously conductive, the solder connection melts due to the heat dissipated in the varistor and the two switch members move rapidly apart. The fusible connection rapidly melts by which time the switch members are sufficiently far apart for no arc to form between them.

Abstract: Overvoltage arrester having a gas-filled housing, including two overvoltage arrester electrodes disposed across from each other in the housing, a tubular insulator body spacing the overvoltage arrester electrodes apart from each other, a ring-shaped flange integral with one of the overvoltage arrester electrodes forming a first spark gap electrode, a ring-shaped metal cap forming a second spark gap electrode being superimposed on the first spark gap electrode and pressed in on the tubular insulator body, the first and second spark gap electrodes forming a spark gap having a given clearance therebetween, and a contact spring connecting the second spark gap electrode to the other of the overvoltage arrester electrodes.

Abstract: A line protector has a housing with coaxial surge voltage arresters, line terminals and a ground terminal. One line terminal is substantially at one end of the cavity of the housing while the other line terminal extends substantially the full length of the cavity of the housing. The ground terminal extends from between the arresters to said one end of the housing cavity. Each terminal projects from the housing at said one end. The three terminals are insultated from the arresters by barrier walls in the housing. A cover closes a side opening in the housing through which the components of the protector are inserted.

Abstract: A surge voltage arrester assembly comprises a primary gas tube surge arrester and an air gap secondary arrester that provides surge protection should the gas tube become vented to atmosphere. The secondary arrester has the air gap defined by a rim of one of the gas tube electrodes and an opposed roughened surface of a metallic cup into which the gas tube is positioned. The roughened cup surface has a coating of graphite applied thereto. The electrode rim may or may not be roughened and/or coated. In a three element version of the invention wherein the gas tube has two line electrodes and a ground electrode, metallic cups are provided at opposite ends of the gas tube to cooperate with the ground electrode for forming secondary air gaps for each line electrode. The cup surfaces at the secondary air gaps are roughened and graphite coated. An O-ring seals each secondary air gap against the entrance of contaminants.

Abstract: A protective module of the type used in building entrance terminals having substantially greater heat sensitivity than prior art types, thereby offering protection against sneak currents which are not sufficiently large to activate conventional solder pellet heat sensors. Use is made of a bobbin type heat sensor, the thermal inertia value of which may be varied to alter sensitivity.

Abstract: Laminar air gap devices include two overlapping conductive layers separated by a non-metallic insulating layer. The insulating layer is perforated to provide at least one air gap between the conductive layers. The devices are positioned between a line electrode and ground electrode of a gas filled surge arrester and resiliently retained thereon by conductive clips. Non-metallic fusible elements, preferably plastic, are interposed between the clip legs and the associated electrode. The fusible element may also be the insulating layer between the conductive layers.

Abstract: A surge voltage arrester utilizes for surge protection a varistor of the zinc oxide type between a line terminal and a ground terminal. The varistor is of a type that has a resistance which decreases as increasing voltage is applied thereacross. With increasing temperature the leakage current through the varistor increases at a given voltage. At a critical temperature and voltage condition, the varistor is subject to a thermal runaway condition which would cause the varistor to fail expelling hot particles. To avoid this failure condition, a fail-safe mechanism is provided which connects the line terminal to the ground terminal by-passing the varistor when there is an overcurrent condition on the line that results in heating of the varistor.

Abstract: Disclosed herein are surge arrester configurations employing non-metallic and preferably plastic fusible elements which normally insulate biased short circuiting members from shorting the surge arrester but which, in the event of certain forms of excessive overloads, fuse to thereby permit the shorting elements to short circuit the arrester gap. In addition, the embodiments include integral backup air gaps to provide additional backup protection covering certain gas tube failure modes. In the illustrated embodiments, the shorting elements each take the form of a conductive clip with one set of spring fingers in electrical contact with the line (end) electrode and another set urged in the direction of the ground electrode but separated therefrom by an annular plastic fusible sleeve coaxially coupled to the center body housing.

Abstract: A line protector for protecting telephone lines and the like from over-voltage or over-current conditions includes a primary arrester element and a secondary arrester element that provides back-up protection upon a fail open of the primary arrester element. The primary arrester comprises a gas tube having spaced electrodes to form an arc gap therebetween. The secondary arrester includes a pair of electrodes axially aligned with the gas tube and separated by an insulating spacer to provide an air gap therebetween. The air gap of the secondary arrester is maintained at a predetermined spacing such that the breakdown voltage thereof is greater than the rated breakdown voltage across the arc gap of the gas tube but less than the breakdown voltage across said arc gap should the gas tube fail open as by being vented to atmosphere.

Abstract: A short circuit clip with legs for resiliently engaging a line and ground electrode of a gas tube arrester includes an air gap device at one set of legs. The air gap device includes a conductor member extending from the clip to contact an arrester electrode and insulated from the clip by a layer of insulation having a hole to form the gap. The air gap device may be releasably connected with the clip or permanently attached. In the former case, a ferrule housing, which acts as an electrode for the air gap, is fitted to the clip. In the latter, the conductor is a rivet which attaches the device to the clip. Non-metallic fusible elements are interposed between the clip legs and associate arrester electrode.

Abstract: A line protector includes a body having first and second end terminals and an intermediate terminal for connection to a ground potential. End caps are mounted on the end terminals and have peripheral edges maintained spaced from the intermediate terminal by means of a displaceable element responsive to excessive currents in the line being protected. High currents will cause the end caps to move toward the intermediate terminal and provide a short circuit therewith to ground to protect telephone equipment connected thereto. The intermediate terminal is mounted in a clip which has centering means formed therein to maintain the mechanical and electrical spacing of the intermediate terminal with respect to the end caps equal to one another. The protector assembly is mounted with a standard housing and base structure to be interchangeable with existing central office plug-in protectors.