Circuit breaker including improved current auctioneering circuit

Claim 2

An auctioneering circuit for obtaining a unidirectional output current which is substantially equal to the output current of only one of a plurality of substantially constant, unidirectional current sources each having a pair of output terminals comprising means for connecting the output terminals of the respective current sources in series circuit relation with the substantially constant unidirectional output currents of said sources arranged to flow in the same direction, said series circuit being connected to a pair of overall output terminals, and rectifier means connected in parallel with the output terminals of each of said current sources, all of said rectifier means being poled in the same direction, the rectifier means associated with each current source being reversely poled with respect to the direction of the output currents of the other current sources, the output current of said auctioneering circuit being substantially equal to only the smallest of the output currents of said current sources.

Claim 3

The combination as claimed in claim 1 wherein each rectifier means comprises a diode.

Claim 4

The combination as claimed in claim 2 wherein an additional Zener diode is connected in series with each diode and oppositely poled with respect to the associated diode.

Claim 5

A three-phase circuit breaker comprising three sets of separable contacts, operating means for opening and closing said sets of contacts, a plurality of current transformers for obtaining three substantially constant alternating output currents which are substantially proportional to the currents in said sets of contacts, three intermediate transformers of the saturating type connected to said current transformers for further stepping down the output currents of said current transformers to a plurality of intermediate, substantially constant alternating output currents, three full wave, bridge rectifier circuits connected respectively to said three intermediate transformers for converting said intermediate, substantially constant alternating output currents to corresponding unidirectional output currents, each of said rectifier circuits comprising a plurality of diodes and a pair of unidirectional current output terminals, means for connecting the output terminals of said bridge circuits in series circuit relation between a pair of overall output terminals with the unidirectional output currents arranged to flow in the same direction whereby the unidirectional output current at said overall output terminals is substantially equal to only the instantaneously highest of the unidirectional output currents of said bridge circuits said diodes of each bridge rectifier circuit associated with one of said alternating output currents during at least certain operating conditions forming a current carrying path between the unidirectional output terminals of the last-mentioned bridge circuit, and means responsive to the output current at said overall output terminals which is substantially equal to only the instantaneously highest of the unidirectional output currents of said bridge circuits for actuating said operating means to open said contacts.

Claim 6

A three-phase circuit breaker comprising three sets of separable contacts, operating means for opening and closing said sets of contacts, a plurality of current transformers for obtaining three substantially constant alternating output currents which are substantially proportional to the currents in said sets of contacts, three intermediate transformers of the saturating type connected to said current transformers for further stepping down the output currents of said current transformers to a plurality of intermediate, substantially constant alternating output currents, three full wave, bridge rectifier circuits connected respectively to said three intermediate transformers for converting said intermediate, substantially constant alternating output currents to corresponding unidirectional output currents, each of said rectifier circuits comprising a plurality of diodes and a pair of unidirectional current output terminals, means for connecting the output terminals of said bridge circuits in series circuit relation between a pair of overall output terminals with the unidirectional output currents arranged to flow in the same direction whereby the unidirectional output current at said overall output terminals is substantially equal to only the instantaneously highest of the unidirectional output currents of said bridge circuits said diodes of each bridge rectifier circuit associated with one of said alternating output currents during at least certain operating conditions forming a current carrying path between the unidirectional output terminals of the last-mentioned bridge circuit, and means responsive to the output current at said overall output terminals which is substantially equal to only the instantaneously highest of the unidirectional output currents of said bridge circuits for actuating said operating means to open said contacts.

Claim 7

The combination as claimed in claim 4 wherein each bridge rectifier circuit comprises four diodes connected between said current transformers and the unidirectional output terminals of said bridge rectifier circuit.

Claim 8

The combination as claimed in claim 4 wherein a resistor is connected to said pair of overall output terminals for developing thereacross a unidirectional output voltage which varies with only the highest output current of said current transformers.