Trip control apparatus of circuit breaker

Abstract

When a voltage (V) of a D.C. power source having an internal resistance (5a) exceeds an "exciting voltage" (FIG. 2), transistors (21, 28 and 33) turn ON, and a transistor (30) turns OFF, and then a tripping winding 16 is excited to close a circuit breaker; on the other hand when the voltage (V) is lowered under a "tripping voltage", the transistor (33) turns OFF and the transistor (30) turns ON, and thereby a load resistor (31) which is less than a resistance 34 of the tripping winding 16 is connected to the D.C. power source; consequently, the voltage V is further lowered by the internal resistance (5a), and a voltage difference is produced between the exciting voltage and the tripping voltage, thus making a "hysteresis characteristic" between the exciting voltage and the tripping voltage.

Dependencies are inferred from the claim text.