Abstract: An electrical current transformer for installation upon a power distribution line including a generally annular, split core and a secondary winding. The secondary winding includes a first winding portion, wound with a first winding polarity about the split core, and a second winding portion, wound with a second, opposite winding polarity about the split core, and a tap. The transformer further includes first and second rectifiers, electrically connecting a tap output to terminals of the first and second winding portion opposite the tap, respectively, and a tap control for controlling the tap output, where the tap is both electrically connectable to the output to provide an additive connection and electrically isolatable from the output to cause a subtractive connection. The tap control controls the tap output in response to a condition sensed in the powered circuit. Self-cancellation may be achieved by using windings having an equal number of turns.

Abstract: A disassociated split sensor coil manufactured from hemi-toroidal cores. Each core includes a surface channel extending from end to end, with wire sections being wound about the core to form a helical sensor coil electrically connected to a connecting wire returned through the surface channel. The connecting wires are interconnected to form a continuous electrical path, with terminal wires being electrically connectable to a monitoring circuit. Also, a method of manufacturing including obtaining a hemi-toroidal core having a surface channel, placing a first length of a wire within the surface channel so as to extend from end to end, winding a second length of the wire so as to form a helical coil section extending from end to end, providing a third length of the wire extending from one end, and repeating the steps to form a disassociated split sensor coil electrically connectable by joining the first lengths of wire.