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US 5,815,353 AGranted
Overvoltage protector
AssigneePilz GmbH & Co. KG
InventorHans Dieter Schwenkel
Life of this patent
Estimating the term…
Abstract
An overvoltage arrester (8) consists of a plurality of limiter elements (15) connected in series. Parallel to this series of limiter elements (15) is a series of controlled switches (18). The two circuits interconnect ladder-style by means of cross links (23), so that individual limiter elements (15) can be tested by closing the switches (18). The limiter elements (15) are dimensioned so that each limiter element (15) has a breakdown or forward voltage which is less than the lowest operating voltage to be expected at the overvoltage line (8).
Claims21
An overvoltage protector, comprising:
- a first and second power terminals,
- at least two limiter means connected in series, whose forward d.c. resistance goes to a high value below a predetermined forward voltage and to a low value above said forward voltage, where the series circuit made up of said limiter means is connected between the first and second power terminals, and where the sum of said forward voltages of at least two limiter means serves to define a maximum permissible voltage between the first and second power terminals, while said forward voltage of each individual limiter means is less than a minimum preselected input voltage at the first and second power terminals that is not zero, and
- a series circuit of switching devices connected across the first and second power terminals, each of the switching devices having a control input, where the number of switching devices equals the number of limiter means, and each of the switching devices can assume either a high-resistance or low-resistance state, and where each node between adjacent switching devices is interconnected with a corresponding node between adjacent limiter means via an electrical cross link.
An overvoltage protector, comprising:
- a first and second power terminals, at least two limiter means connected in series, whose forward d.c. resistance goes to a high value below a predetermined forward voltage and to a low value above said forward voltage, where the series circuit made up of said limiter means is connected between the first and second power terminals, and where the sum of said forward voltages of at least two limiter means serves to define a maximum permissible voltage between the first and second power terminals, while said forward voltage of each individual limiter means is less than a minimum preselected input voltage at the first and second power terminals that is not zero, and a series circuit of switching devices connected across the first and second power terminals, each of the switching devices having a control input, where the number of switching devices equals the number of limiter means, and each of the switching devices can assume either a high-resistance or low-resistance state, and where each node between adjacent switching devices is interconnected with a corresponding node between adjacent limiter means via an electrical cross link, wherein each cross link includes a current sensor.
Dependencies are inferred from the claim text.