U.S. patent number 3,710,191 [Application Number 05/189,677] was granted by the patent office on 1973-01-09 for overvoltage arrester with several electrodes. This patent grant is currently assigned to Siemens Aktiengesellschaft. Invention is credited to Gerhard Peche.
United States Patent | 3,710,191 |
Peche | January 9, 1973 |
In order to avoid transverse voltages between associated conductor pairs without additional deflectors, particularly in the case of symmetrical wiring of telecommunication lines with overvoltage arresters, a gas discharge lightning arrester is proposed comprising two principal electrodes and one secondary electrode, as well as a ground electrode located symmetrically with respect to the principal electrodes, the ground electrode together with the two principal electrodes forming two principal discharge paths whose response for which is higher than that of a secondary discharge path defined by the principal electrodes. BACKGROUND OF THE INVENTION 1. Field of the Invention This invention relates to an overvoltage arrester having several electrodes facing each other in a gas-tight discharge vessel, the electrodes electrically insulated and spaced from one another and defining at least two discharge paths. 2. Description of the Prior Art In order to protect electrical installations, particularly telecommunication systems, it is generally known to utilize gas-filled overvoltage arresters, commonly called button arresters. Generally, such overvoltage arresters comprise two spaced metallic electrodes insulated from one another and facing each other in a gas-tight discharge vessel. In addition, so-called multiple path arresters are known which contain at east three electrodes which define several discharge paths (compare for example German Pats. 729,803 and 930,400). In these multiple path arresters of the prior art, all discharge paths have substantially the same response voltage. The purpose of a multiple path arrester resides in the fast ignition of the discharge paths in response to a pre-ionization caused by a first discharge over one of the paths. When wiring telecommunication conductors with overvoltage arresters, one arrester is placed between the individual conductors to be protected against overvoltages, and the ground. Because the ignition voltages of the arresters do not precisely agree, so that in case of a voltage surge they will not ignite simultaneously, transverse voltages can occur for a short time between the two conductors associated as a conductor pair, like the A and B conductors of telephone lines. To avoid such transverse voltages which have particularly harmful effect in telephone lines, particularly those telephone lines which have transistor amplifiers connected thereto, steps must be taken to compensate the voltages between the conductor pairs. For that purpose, protective circuits have been disclosed, all of which require at least three arresters (see for example German published application 1,462,168). It also has been attempted to avoid the occurrence of transverse voltages by utilizing multiple path arresters. However, transverse voltages cannot be eliminated completely with the multiple path arresters of the prior art, because in spite of the pre-ionization following ignition of the first discharge path, the remaining discharge paths respond with a certain ignition delay. In practice, therefore, when wiring telephone lines with multiple path arresters, an additional arrester having a low response voltage, for example, a 90-volt arrester, is connected between the A and B conductors. SUMMARY OF THE INVENTION The present invention therefore has as it primary object the provision of an overvoltage arrester which protects conductors associated in pairs both against voltage surges and against transverse voltages without the need of additional arresters or circuit members. The foregoing objective is realized through the design of an overvoltage arrester of the kind mentioned above wherein a ground electrode is arranged symmetrically with respect to two principal electrodes, wherein the two principal electrodes form a secondary discharge path therebetween, and wherein the two principal electrodes together with the ground electrode form two principal discharge paths whose response voltage is higher than that of the secondary discharge path. A protective spark gap with two stationary principal electrodes insulated from each other within a chamber that is placed under a high vacuum and surrounded by stationary trigger electrodes has been disclosed in the German published application 1,463,149. However, in that structure, the one principal electrode is to be connected with a conductor to be protected and the other principal electrode is to be connected to ground in contrast with the structure of the present invention wherein both principal electrodes are placed electrically parallel with a ground electrode. The present invention makes it possible to effectively protect conductors associated in pairs, on which voltage surges are to be expected, with a single overvoltage arrester in such a manner that as voltage surges occur between the conductors, harmful transverse voltages are avoided. An overvoltage arrester according to the invention is intended in particular for use in telephone installations having input and intermediate amplifiers equipped with transistors. Therefore, the two principal electrodes of the arrester are associated in each case with the A and B conductors of a telephone line, while the ground electrode is connected to a reference potential, usually ground. As soon as the telephone or telecommunication line is subjected to an inadmissibly high voltage surge, one of the two principal discharge gaps ignites. Unless it just so happens that at precisely the same time the second principal discharge path or gap also responds, transverse voltages between the A and B conductors of the conductor pair affected are compensated by way of a secondary discharge path which has a lower response voltage, whereby the accomplished ignition of a principal discharge path causes the secondary discharge path to ignite at an accelerated rate by pre-ionization thereof. As it is known, the response voltage of a gas discharge over-voltage arrester substantially depends on the electrode distances, the composition of the electrode surfaces and on the gas load. Since the discharge gaps of an overvoltage arrester according to the invention are all placed in the same discharge vessel, the desired differential response voltages of the principal discharge gaps on the one hand and of the secondary discharge gap on the other hand are accomplished by differential electrode distances and/or different activations of the electrodes. To prevent the ignition operation of a principal discharge path from influencing the secondary discharge gap, it is recommended to physically separate the secondary discharge gap from the principal discharge gaps. A detrimental influence of the principal discharge gaps upon the secondary discharge gap must be taken into consideration, particularly in high performance arresters, where physically extended principal electrodes are needed to arrest powerful current surges. Therefore, if a principal discharge gap ignites at a point located at a great distance from the secondary discharge path, a pressure wave in the direction toward the secondary discharge gap not yet ignited must be anticipated because of the heating of the gas present in the arrester. This pressure wave could lead, without physical separation of principal and secondary discharge gaps, to an increase of the response voltage of the secondary discharge gap. A separation of the discharge gaps is easily accomplished by appropriate electrode design. For example, in an arrester having a concentric structure, where the ground electrode coaxially surrounds two pin-shaped principal electrodes, the ends of the secondary discharge gap will be decreased between the principal electrodes defining the gap by providing tapered ends of the principal electrodes.
Inventors: | Peche; Gerhard (Berlin, DT) |
---|---|
Assignee: | Siemens Aktiengesellschaft
(N/A) |
Family ID: | 5790348 |
Appl. No.: | 05/189,677 |
Filed: | October 15, 1971 |
Dec 8, 1970 [DT] | P 20 60 388.7 | |||
Current U.S. Class: | 361/120; 313/306; 313/581 |
Current CPC Class: | H01T 4/12 (20130101) |
Current International Class: | H02H 9/04 (20060101); H01J 17/38 (20060101); H02h 009/04 () |
Field of Search: | ;337/28,29,32,34 ;317/61,61.5,62 ;315/35,36 ;313/214,217,283,306,307,308 |
3564473 | February 1971 | Kawiecki |
3522570 | August 1970 | Wanaselja |
uspto.report is an independent third-party trademark research tool that is not affiliated, endorsed, or sponsored by the United States Patent and Trademark Office (USPTO) or any other governmental organization. The information provided by uspto.report is based on publicly available data at the time of writing and is intended for informational purposes only.
While we strive to provide accurate and up-to-date information, we do not guarantee the accuracy, completeness, reliability, or suitability of the information displayed on this site. The use of this site is at your own risk. Any reliance you place on such information is therefore strictly at your own risk.
All official trademark data, including owner information, should be verified by visiting the official USPTO website at www.uspto.gov. This site is not intended to replace professional legal advice and should not be used as a substitute for consulting with a legal professional who is knowledgeable about trademark law.