Solid state overcurrent detector

Claim 2

A solid state overcurrent detector comprising: a current sensor means provided for respective phases of AC power lines for issuing a first output signal corresponding to effective values or mean values of currents of respective phase and a second output signal corresponding to a highest peak value of said currents of respective phases, first level discrimination means for discriminating levels of said first output signal of said current sensor means, first time-current operating means for issuing a first time-current operating signal responding to output signal of said first level discrimination means, first output means for issuing overcurrent detection signal responding to output signal of said first time-current operating means, second level discrimination means for discriminating level of said second output signal from said current sensor means, second time-current operating means for issuing a second time-current operating signal responding to output signal of said second discrimination means, and second output means for issuing overcurrent detection signal responding to output signal of said second time-current operating means.

Claim 3

A solid state overcurrent detector in accordance with claim 1, which further comprises: peak value detection means provided as a stage between said current sensor means and said first level discrimination means for detecting a peak value among said output signals of said current sensor means and issuing an output signal to said first time-current operating means.

Claim 4

A solid state overcurrent detector in accordance with claim 2, wherein said first peak detection means is a diode OR circuit.

Claim 5

A solid state overcurrent detector in accordance with claim 1, 2 or 3, wherein said current sensor means comprises burden circuits connected with its one end to a common potential point, and a diode OR circuit for obtaining said second output signal from the output signals of said burden circuits.

Claim 6

A solid state overcurrent detector in accordance with claim 1, 2 or 3, wherein at least one of said first time-current operating means or said second time-current operating means comprises starting means for starting time-current operation when input signal becomes above a predetermined level and a resetting means for resetting said time-current operation when said input signal becomes below a predetermined level.

Claim 7

A solid state overcurrent detector in accordance with claim 5, wherein when input signal to at least one of said first and second time-current operating means becomes below a predetermined level, said resetting means carries out a resetting along a predetermined heat discharging rate characteristic.

Claim 8

A solid state overcurrent detector in accordance . with claim 1, 2, 3 or 6, wherein at least one of said first discrimination means and said first time-current operating means comprises a microcomputer.

Claim 9

A solid state overcurrent detector in accordance with claim 7, wherein said second level discrimination means and said second time-current operating means are connected in a substantially direct way without data processing with each other.

Claim 10

- A solid state overcurrent detector in accordance with claim 7, wherein said first time-current operating means has an inverse time-current characteristic.

Claim 11

A solid state overcurrent detector in accordance with claim 8, wherein said second time-current operating means has an instant-responsive characteristic.

Claim 12

A solid state overcurrent detector in accordance with claim 1, 2 or 3, wherein said current sensor means has a means for rectifying detection current into DC current, thereby feeding it as operation power for whole circuit of the solid state overcurrent detector.

Claim 13

A solid state overcurrent detector in accordance with claim 1, 2 or 3, wherein said first and second output means is a single means which receives both output signals of said first and second time-current operating means through an OR circuit.

Claim 14

A circuit interrupter comprising: disconnectable contacts provided in respective lines of a set of AC power lines, a releasing device for actuation of disconnection of said disconnectable contacts, and control means for controlling operations of said releasing means responding to an overcurrent under a predetermined condition, said control means comprising: current sensor means provided for respective phases of said AC power lines for issuing a first output signal corresponding to effective values or mean values of currents of respective phases and a second output signal corresponding to a highest peak value of said currents of respective phases, first level discrimination means for discriminating levels of said first output signal of said current sensor means, first time-current tripping means for issuing a first time-current tripping signal responding output signal of said first level discrimination means, first output means for issuing overcurrent detection signal responding to output signal of said first time-current tripping means, second level discrimination means for discriminating level of said second output signal from said current sensor means, second time-current tripping means for issuing a second time-current tripping signal responding output signal of said second discrimination means, and second output means for issuing overcurrent detection signal responding to output signal of said second time-current tripping means.

Claim 15

A circuit interrupter comprising: disconnectable contacts provided in respective lines of a set of AC power lines, a releasing device for actuation of disconnection of said disconnectable contacts, and control means for controlling operations of said releasing means responding to an overcurrent under a predetermined condition, said control means comprising: current sensor means provided for respective phases of said AC power lines for issuing a first output signal corresponding to effective values or mean values of currents of respective phases and a second output signal corresponding to a highest peak value of said currents of respective phases, first level discrimination means for discriminating levels of said first output signal of said current sensor means, first time-current tripping means for issuing a first time-current tripping signal responding output signal of said first level discrimination means, first output means for issuing overcurrent detection signal responding to output signal of said first time-current tripping means, second level discrimination means for discriminating level of said second output signal from said current sensor means, second time-current tripping means for issuing a second time-current tripping signal responding output signal of said second discrimination means, and second output means for issuing overcurrent detection signal responding to output signal of said second time-current tripping means.

Claim 16

A circuit interrupter in accordance with claim 13, which further comprises: peak value detection means provided as a stage between said current sensor means and said first level discrimination means for detecting a peak value among said output signals of said current sensor means and issuing an output signal to said first time-current tripping means.

Claim 17

A circuit interrupter in accordance with claim 14, wherein said first peak detection means is a diode OR circuit.

Claim 18

A circuit interrupter in accordance with claim 13, 14 or 15, wherein said current sensor means comprises burden circuits connected with its one end to a common potential point, and a diode OR circuit for obtaining said second output signal from the output signals of said burden circuits.

Claim 19

A circuit interrupter in accordance with claim 13, 14 or 15, wherein at least one of said first time-current tripping means or said second time-current tripping means comprises starting means for starting time-current operation when input signal becomes above a predetermined level and a resetting means for resetting said time-current operation when said input signal becomes below a predetermined level.

Claim 20

A circuit interruptor in accordance with claim 17, wherein when input signal to at least one of said first and second time-current operating means becomes below a predetermined level, said resetting means carries out a resetting along a predetermined heat discharging rate characteristic.

Claim 21

A circuit interruptor in accordance with claim 13, 14, 15 or 18, wherein at least one of said first discrimination means and said first time-current tripping means comprises a microcomputer.

Claim 22

A circuit interruptor in accordance with claim 19, wherein said second level discrimination means and said second time-current tripping means are connected in a substantially direct way without data processing with each other.

Claim 23

A circuit interruptor in accordance with claim 19, wherein said first time-current tripping means has an inverse time-current characteristic.

Claim 24

A circuit interruptor in accordance with claim 20, wherein said second time-current tripping means has an instant-responsive characteristic.

Claim 25

A circuit interruptor in accordance with claim 13, 14 or 15, wherein said current sensor means has a means for rectifying detection current into DC current, thereby feeding it as operation power for said control means.

Claim 26

A circuit interruptor in accordance with claim 13, 14 or 15, wherein said first and second output means is a single means which receives both output signals of said first and second time-current operating means through an OR circuit.