Circuit breaker with improved single coil actuator and undervoltage release mechanism

Claim 2

A circuit interrupter, comprising: separable contacts; trip means operable upon actuation to effect separation of said contacts; and a releasable actuator comprising: an actuating member operable between first and second conditions, said actuating member actuating said trip means when operated to said second condition; means for biasing said actuating member toward said second condition; unitary operating means for operating said actuating member between said first and second conditions, said operating means being disposed in relation to said actuating member and responsive to a single control signal; and control means connected to said operating means for generating said control signal, said control means being coupled to said contacts and to control terminals, said control means being responsive to overcurrent conditions through said contacts and undervoltage conditions at the control terminals to cause said operating means to operate said actuating member to said second condition, thereby effecting release of said trip means and separation of said contacts.

Claim 3

A circuit interrupter as recited in claim 1 wherein said bias means comprises a spring.

Claim 4

A circuit interrupter as recited in claim 1 wherein said operating means comprises electromagnetic means.

Claim 5

A circuit interrupter as recited in claim 3 wherein said actuating member comprises a generally cylindrical plunger and said electromagnetic means comprises a single coil wound coaxially about said plunger.

Claim 6

A circuit interrupter as recited in claim 4 wherein said release actuator comprises a housing supporting said plunger, said bias means, and said coil.

Claim 7

A circuit interrupter as recited in claim 5 wherein said coil is wound upon a hollow cylindrical coil form coaxially surrounding said plunger.

Claim 8

A circuit interrupter as recited in claim 1 wherein said control means generates said control signal whenever voltage at the control terminals is above a predetermined voltage level, said control means ceasing generation of said control signal whenever voltage at the control terminals falls below the first predetermined level and whenever current through said contacts rises above a predetermined current level.

Claim 9

A circuit interrupter as recited in claim 7 wherein said control means comprises an electronic circuit coupled to the control terminal and to said contacts, said control signal comprising a flow of current through said coil.

Claim 10

A circuit interrupter as recited in claim 8 wherein said control means further comprises current transformer means coupled to said contacts and said electronic circuit comprises a voltage sensing circuit connected to the control terminals, an overcurrent sensing circuit connected to said current transformer means, and a current control circuit connected in series circuit relationship with said coil; said voltage sensing circuit and said current sensing circuit being connected to said current control circuit and activating said current control circuit to cut off current flow to said coil whenever undervoltage conditions occur at the control terminals and whenever overcurrent conditions occur through said contacts.

Claim 11

A circuit breaker as recited in claim 7 wherein said current control circuit comprises switch means having switch output terminals operable between on and off conditions and a switch control terminal, said switch output terminals being connected in series circuit relationship with said coil, and said switch control terminal being connected to said voltage sensing circuit and said overcurrent sensing circuit.

Claim 12

A circuit interrupter as recited in claim 10 wherein said switch means comprises a transistor.

Claim 13

A circuit interrupter as recited in claim 11 wherein said switch output terminals comprise the emitter and collector of said transistor, said switch control terminal comprises the base of said transistor, and said current control circuit further comprises a Zener diode connected between said collector and said base.

Claim 14

A multipole circuit interrupter, comprising: an interrupter housing; a plurality of pairs of separable contacts supported within said housing; trip means supported within said housing and operable upon actuation to effect substantially simultaneous separation of each of said contact pairs; a release actuator supported within said housing and comprising: a support structure; an actuating member movable between first and second positions, said actuating member actuating said trip means when operated to said second position; means for biasing said actuating member toward said second position; and operating means disposed in relation to said actuating member and responsive to a single control signal for operating said actuating member between said first and second conditions; and control means connected to said operating means for generating said control signal, said control means being coupled to said contacts and to control terminals, said control means responsive to overcurrent conditions through said contacts and undervoltage conditions at the control terminals to cause said operating means to operate said actuating member to said second condition, thereby effecting release of said trip means and separation of all of said contact pairs.

Claim 15

A multipole circuit interrupter, comprising: an interrupter housing; a plurality of pairs of separable contacts supported within said housing; trip means supported within said housing and operable upon actuation to effect substantially simultaneous separation of each of said contact pairs; a release actuator supported within said housing and comprising: a support structure; an actuating member movable between first and second positions, said actuating member actuating said trip means when operated to said second position; means for biasing said actuating member toward said second position; and operating means disposed in relation to said actuating member and responsive to a single control signal for operating said actuating member between said first and second conditions; and control means connected to said operating means for generating said control signal, said control means being coupled to said contacts and to control terminals, said control means responsive to overcurrent conditions through said contacts and undervoltage conditions at the control terminals to cause said operating means to operate said actuating member to said second condition, thereby effecting release of said trip means and separation of all of said contact pairs.

Claim 16

A multipole circuit breaker as recited in claim 13 wherein said unitary operating means comprises electromagnetic means.

Claim 17

A multipole circuit interrupter as recited in claim 14 wherein said actuating member comprises a generally cylindrical plunger.

Claim 18

A multipole circuit interrupter as recited in claim 15 wherein said electromagnetic means comprises a coil wound coaxially about said plunger.

Claim 19

A multipole circuit interrupter as recited in claim 16 wherein said operating means comprises a cylindrical coil form having a hollow core, said coil being wound upon said coil form, said plunger being reciprocally movable within the hollow core of said coil form.

Claim 20

A multipole circuit interrupter as recited in claim 17 wherein said support structure comprises a hollow cylindrical housing of magnetic material surrounding said coil, said coil form, and said plunger; said cylindrical housing being mounted upon said trip means.

Claim 21

A multipole circuit interrupter as recited in claim 13 wherein said operating means comprises a single coil disposed about said actuating member and operable when energized to generate magnetic flux sufficient to overcome the action of said bias means and maintain said actuating member in said first condition, thereby preventing actuation of said trip means, deenergization of said coil permitting said bias means to move said actuating member to said second condition and effect actuation of said trip means.