Bbc Brown, Boveri & Company, Limited

Abb Management Ag

Hans Schar

Diethard Hansen

Niyazi Ari

Hendrik Hoitink

Felix Gassmann

Henk Hoitink

Rolf Muller

In TEM waveguide arrangements such as are used in testing the electromagnetic compatibility of electronic devices in electromagnetic fields, a plate-shaped inner conductor is connected via electrically parallel-connected tubular resistors to an electrically conductive, spherical rear wall. This rear wall is electrically connected to an outer conductor and grounded. Radio-frequency absorbers are mounted on the rear wall for the purpose of absorbing TEM waves, the RF short-point absorbers adjacent to the tubular resistor being smaller than the remaining RF long-point absorbers, in order to reduce the capacitive influence of the tubular resistors. Identical tubular resistors are arranged perpendicular to the plane of the drawing of FIG. 1 in accordance with a current density distribution in such a way that they are more closely adjacent at the edge than in the middle of the inner conductor.

TEM waveguide arrangement

Zinc oxide surge arresters are used to replace capacitive elements for voltages below the pick-up voltage of the surge arrester. Advantageously, the surge arresters may be provided in an alternating current network to provide a high degree of protection against transient disturbances without increasing cost.

Zine oxide surge arresters

A gas-filled test cell is used which accommodates the object under test and to which a pulse generator is connected. The test cell is constructed over its entire length as a coaxial line having a ribbon-shaped inner conductor and a round outer conductor. A ribbon-shaped potential plate connected to the outer conductor is arranged plane-parallel to the inner conductor inside the outer conductor at a distance corresponding to at least twice the height of the object under test. The distance is also longer than the shortest distance between the inner conductor and the outer conductor. The ratio between the sum of the width of the inner conductor and its thickness and the diameter of the outer conductor has been selected in such a manner that is between 0.4 and 0.9.

Device for testing electrical or electronic systems with electromagnetic

The present invention relates to a protective device for a load connected to a power supply line of an electric power system, comprising an LC network having low-pass characteristics, connected into the power supply line on the system side preceding the load. So that disturbances with frequencies below the cut-off frequency of the LC network can also be kept away from the load, a switching element controlled by a monitoring device is arranged according to the invention in series with the LC network in the power supply line. The monitoring device is connected to the power supply line on the system side at a junction preceding the switching element and keeps the switching element closed only for as long as the instantaneous value of the time derivation of the voltage on the power supply line deviates from the instantaneous value of a nominal value which is predeterminable in its variation with time, by no more than an equally predeterminable amount.

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Basel, Switzerland

Hans Schar