Circuit breaker testing apparatus having adjustable inductor for controlling magnitude of current flow

A circuit breaker testing apparatus, comprising:

• (a) an electrical circuit having leads terminated by electrical connectors for connection to terminals of a circuit breaker for providing a source of electrical power to said electrical circuit from the circuit breaker;
• (b) an adjustable inductor electrically connected in said electrical circuit for producing an adjustable electrical load on the circuit breaker, said adjustable inductor including
• (i) an electrical conductor coil electrically connected in said electrical circuit, and
• (ii) a ferromagnetic core spaced apart from said coil and being movable relative to said coil in first and second opposite directions so as to continuously vary the impedance to said flow of current through said coil in said electrical circuit until the circuit breaker is tripped;
• (c) means for sensing current flow in said electrical circuit;
• (d) indicator means electrically connected to said current sensing means for producing a reading of the magnitude of current flow in said electrical circuit and for displaying and holding the reading of the highest magnitude of current flow reached in said electrical circuit and thereby the magnitude of current flow at which the circuit breaker is tripped by the adjustment of the electrical load on the circuit breaker;
• and
• (e) means for adjusting said adjustable inductor so as to reduce the electrical load produced on the circuit breaker and thereby increase the magnitude of current flow drawn through the circuit breaker circuit to cause tripping of the circuit breaker, said adjusting means including
• (i) a movable control member, and
• (ii) a linkage connected to and extending between said control member and said core of said adjustable inductor such that moving said control member causes said linkage to move said core relative to said coil in one of said first and second opposite directions to decrease the impedance provided in said coil by said core and thereby allow the magnitude of current flow through said electrical circuit to increase until the circuit breaker is tripped.