| 摘要 |
<p>PURPOSE:To enable accurate and highly reliable detection of a signal current waveform, by switching a current transformer over to an air-core type, namely, a Rogowskii coil from a general cored type to lower a magnetization storage thereof. CONSTITUTION:An air-core current transformer, namely, Rogowskii coils 21 and 22 are arranged between pallet switch contacts 3 and 4 and a load side voltage terminal 11. When a closing signal is given to a closing signal terminal 12, a signal current flows to the load side voltage terminal 11 through a closing coil 1 and the pallet switch contact 3 and a breaker body operates to open an electrode at the pallet switch contact 3. Under such a condition, a current waveform detected with a current transformer 21 is inputted to a time measuring device 7 via an integration circuit 23 to judge the presence of abnormality in the operation of the breaker depending on whether a time range of the waveform is within an allowable value of a reference operating time or not and a data is outputted at a terminal 9 corresponding to the degree of the abnormality. On the other hand, also when a trip signal is applied to a shielding signal terminal 13, the same operation is done.</p> |
