| 摘要 |
A residual current device for an AC electricity supply comprises a housing (10) and a first load conductor (L) inside the housing connected in series between the supply and a load and including a set of contacts (18) by which an electrical connection between the supply and the load may be made or broken. A current transformer is disposed inside the housing and has a toroidal core (TI) the first load conductor passing through the core and forming one primary winding of the current transformer. At least one further load conductor (N) outside the housing passes through the core (T) via an opening (32) in the housing and forms a further primary winding of the current transformer. A secondary winding (W) on the core produces an output in response to a residual current, and a circuit (RCC) inside the housing is responsive to the output on the secondary winding to open the contacts if the residual current is above a predetermined level. |
