| 摘要 |
1,191,230. Switchgear structures. BROWN, BOVERI & CO. Ltd. 3 Oct., 1968 [5 Oct., 1967], No. 46989/68. Heading H1N. [Also in Division G1] In order to enable equipment such as a circuit-breaker P, contained within an earthed metal enclosure to be tested for partial discharges, a conductor extends via an insulating gland through the enclosure wall, e.g. at T, to the equipment P for connecting it to an external high voltage source, while a detector circuit within and screened by the enclosure detects the presence of a partial discharge, the circuit including a capacitor CK and resistor A in series between the equipment P and enclosure wall. An output lead M passes via an insulating gland through the enclosure wall and is connected to the junction of the capacitor and resistance. A filter F may be included in the conductor via which high voltage is applied to the equipment P, while in use the output lead is connected to a measuring station. The detecting circuit is mounted with the resistor coaxial within a cylindrical chamber MK which is bolted on to the switch capsule KS. Two symmetrically placed resistors in parallel may alternatively be used. A low output voltage may be derived via a transformer T also coaxially disposed in the chamber MK, the transformer primary being connected in series with a choke L to a tapping point in the capacitor chain CK. |
