Electricity: electrical systems and devices – Safety and protection of systems and devices – High voltage dissipation
Patent
1997-04-21
1998-11-03
Gaffin, Jeffrey A.
Electricity: electrical systems and devices
Safety and protection of systems and devices
High voltage dissipation
361127, 361131, H02H 100
Patent
active
058318089
DESCRIPTION:
BRIEF SUMMARY
FIELD OF THE INVENTION
The present invention relates to a low voltage lightning arrester device of the type used particularly to ensure the protection of electronic materials.
BACKGROUND OF THE INVENTION
It is known that the phenomenon of lightning gives rise to instantaneous currents which can be extremely great and can reach in certain cases 10,000 to 100,000 amperes with voltages which can reach 10 to 20 millions of volts for extremely short times. So as to ensure the protection of electronic apparatus against lightning, there is interposed in the supply circuit of the apparatus lightning arrester devices constituted by components which, in normal circumstances, behave as neutral elements, but which, in the case of abrupt overvoltage due to lightning, become conductors and thus ensure the insulation of the apparatus by deflecting to the ground the current generated by the lightning.
A good lightning arrester adapted to protect electronic apparatus must have three essential qualities. On the one hand, it must have high speed of increase of current so as to deflect rapidly to the ground the energy of the lightning which, otherwise, would destroy the electronic material. The speed of increase of the current will be all the higher as the inductance of the lightning arrester is low. It must therefore be able to preserve for a sufficiently long time its effectiveness so that the deflection to the ground of the energy will last for a sufficiently long time so as to permit operation of the conventional disconnection means. This time of effectiveness is all the greater as the mechanical resistance, in all directions, of the lightning arrester is high. It must finally be adapted to be emplaced and removed repeatedly on and from its support.
There is conventionally used, to ensure such functions, gas dischargers. These gas dischargers have substantial drawbacks, and particularly they have a substantial delay, so that in certain cases and particularly in the case of particularly violent and rapid lightning, the deterioration of the electronic apparatus takes place before the grounding of the lightning current by the discharger.
There are also known lightning arrester devices constituted by cylindrical tubular elements enclosing varistors and/or zener diodes, embedded in an insulating resin. Such devices must, in a particularly reduced volume, be able to direct to the ground very high impulsional currents whilst maintaining acceptable voltages at their terminals. It will thus be seen that the power developed in such lightning arrester systems can reach excessively high values. Thus, a resistance has the possibility of transmitting currents of the order of 5,000 amperes for a time of the order of 10 microseconds, whilst maintaining the voltage at its terminals at a value of about 1,500 volts. The power thus developed in such a resistance is of the order of 7.5 megawatts. Such powers developed during extremely short times, in volumes that are also reduced, are extremely difficult to channel, such that lightning arrester devices sometimes behave as veritable miniature "bombs", with the result, in addition to the destruction of the lightning arrester device itself, the destruction of the electronic elements they are supposed to protect.
Lightning arresters are also known which are employed in high voltage energy lines used for the distribution of electric current. In these energy lines, according to the impedance of the electric current supply transformer arranged upstream of the lightning arrester, the currents developed can reach peak values of 6 to 25 kiloamperes for periods of the order of 100 microseconds. To ensure the protection of the installations, it is essential that the lightning arresters that are used maintain the ground, as cutoff devices, such as disconnectors, do not themselves ensure opening the line. It is therefore particularly important at least to retard the destruction of such lightning arresters, until the actuation of the disconnect devices. However, the components used in the construction o
REFERENCES:
patent: 4228478 (1980-10-01), Jakszt et al.
patent: 4656555 (1987-04-01), Raudabaugh
patent: 4910632 (1990-03-01), Shiga et al.
patent: 4940961 (1990-07-01), Thuries et al.
patent: 5043838 (1991-08-01), Sakich
patent: 5218508 (1993-06-01), Doone
patent: 5291366 (1994-03-01), Giese et al.
patent: 5402100 (1995-03-01), Urbanek et al.
patent: 5517382 (1996-05-01), Leupp et Al.
patent: 5559663 (1996-09-01), Tanaka et al.
patent: 5602710 (1997-02-01), Schmidt et al.
patent: 5652690 (1997-07-01), Mansfield et al.
Gaffin Jeffrey A.
Sherry Michael J.
LandOfFree
Lightning arrester device does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Lightning arrester device, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Lightning arrester device will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-696509