Improvements in or relating to electrical disconnect contractors

摘要

A low-profile electrical contactor is provided comprising at least one electrical contact switch, an actuation means and a current determining device. The or each electrical contact switch has first and second electrical terminals, an electrically-conductive busbar in electrical communication with the first electrical terminal, the busbar having two end faces between which a current can flow in a flow direction and at least two flat sides in parallel with the flow direction, at least one fixed electrical contact which is attached to the busbar, an electrically-conductive moveable arm in electrical communication with the second electrical terminal, and at least one moveable electrical contact which is attached to the electrically-conductive moveable arm to form an electrical contact set with the fixed electrical contact. The actuation means can actuate the electrically-conductive moveable arm of the or each electrical contact switch between open and closed conditions. The current determining device has a first field-modifying element formed of a magnetic material located at or adjacent to the first end face of the busbar, a second field-modifying element formed of a magnetic material and located at or adjacent to the second end face of the busbar, at least one sensing coil at or adjacent to the busbar and the first and second field-modifying elements, and having a coil axis between planes of the first and second flat sides. An electromagnetic field induced by the current flowing in the busbar is modified by the first and second field-modifying elements to extend more or substantially more in parallel with the coil axis of the sensing coil.