| 摘要 |
<p>The high sensitivity differential relay acts on a given threshold level of current which is the vectorial sum of circulating currents in the associated distribution network. The relay is intended to provide protection against overloads of about 30mA to 50mA, i.e. that level likely to cause electrocution. The threshold detector is two winding soft iron cored relay which operates through a series of pinions providing amplification of the initial relay armature movement to the contactor actually breaking the supply circuit. The speed of response and sensitivity to overload duration is governed by the pinion inertia. Overall geometry is minimised by having only two pinion planes.</p> |
