Electrical ground fault detector with transformer coupling, a battery supply source and battery charging means

Claim 1

A ground fault detector for conductors of an electrical supply system comprising, in combination, a. current transformer means responding to current imbalance in said supply conductors for exhibiting an induced voltage therein, including a primary ring-type current transformer having a winding adapted to surround a plurality of conductors of a supply line carrying alternating current; b. a second ring-type transformer attached to said primary transformer, forming a unitary structure therewith, having a winding adapted to surround one of said conductors; c. current responsive means including the gate circuit of a silicon-controlled rectifier energized from the winding of said primary transformer, being operable upon imbalance of the current carried in said supply line to indicate a ground fault; d. a battery in circuit with said current responsive means for supplying power to said silicon-controlled rectifier; and e. a circuit including a rectifier connected to the winding of said seCondary transformer for charging said battery.