Asea Brown Boveri Inc.

Dieter Koster

Diethard Hansen

Dietrich Konigstein

An electrical system contains two current-fed components having respective grounded housings. Each of these components is connected via a respective conductor to a common ground point. A signal-transmitting connection galvanically connects the housings two components to each other. A parasitic-current indicator is permanently installed in the system and detects parasitic currents (I.sub.S) flowing between the grounded housings and generates a warning at a predetermined signal level.

Parasitic-ground current indicator for electrical system

A device for calibrating and testing ring-shaped current clamps comprises a calibration housing with an outer conductor enclosing the current clamp, and an inner conductor passing through the current clamp. The outer conductor encloses the current clamp on all sides and is adapted to the shape of the current clamp. The calibration housing also exhibits, with the current clamp accommodated therein, an impedance Z.sub.L which is predetermined by a measuring system. These measurement make it possible to measure the frequency response of the current clamp precisely, up into the GHz range. The calibration housing exhibits transitions which are conically tapered towards the connections (6, 7).

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Turgi, Switzerland

Dieter Koster