To carry out energization tests without irregularity in current supplied to an electric apparatus to be tested and energization tests with the current regulated through simple adjustment to a gap of a current regulator by setting to a dielectric voltage regulator power source system, the current regulator in which a pair of iron cores separable and adjustable in gap surround an energization conductor from a current transformer to the electric apparatus to be tested, and which regulates a self inductance of the energization conductor by adjusting the gap of the iron cores, thereby regulating the current supplied to the electric apparatus to be tested.

The apparatus for carrying out an energization test to test breakers 3A-3B through a current transformer 2 from a three-phase dielectric voltage regulator 4 is provided with current regulators 5A-5C having gap adjustment mechanisms. The current regulator has iron cores which surround a conductor for supplying electricity from the current transformer to the test breaker and, a gap of iron cores can be adjusted manually or by driving an electric motor. The current regulator is constructed to surround the conductor by the separable first and second iron cores each having a U section. The gap of the iron cores is adjusted by sliding the iron cores manually or by driving the electric motor, thereby regulating a current.