Load sensing and power application circuit

Claim 2

In a circuit for controlling the application of a source of AC power to a load: a pair of output terminals across which the load is connected; and means responsive to the connection of the load across both of the terminals for applying AC power from the source to both of said terminals, and responsive to removal of the load for interrupting the application of power to both of said output terminals.

Claim 3

In a circuit for controlling the application of a source of AC power to a load as set forth in claim 1, wherein said responsive means includes: a bidirectional AC switching device having a pair of main terminals and a gating terminal; means for connecting the main terminals across the source of AC power; means for applying the potential applied from the AC source through the load and gating terminal to operate said switching device; a relay having energizing terminals and having contacts interconnecting the source of AC power and both said output terminals; and means for connecting the relay energizing terminals across the source of AC power to energize the relay.

Claim 4

In a circuit interconnecting a source of AC power and a load: a selectively operable means for applying power to said load when said operable means is in an operated state and for precluding the application Of power to the load when said operable means is in an unoperated state; a bidirectional electronic AC device having two main terminals and a gating terminal for initiating conduction between said main terminals in both directions; means connecting said main terminals across the AC power source, one of said terminals being connected between said selectively operable means and the AC power source; means connecting said gating terminal and one of said main terminals across said load for initiating conduction of said electronic AC device; and means responsive to the conduction of said device for operating said precluding means to apply power from said source to said load.

Claim 5

In a circuit interconnecting a source of AC power and a load: a selectively operable means for applying power to said load when said operable means is in an operated state and for precluding the application Of power to the load when said operable means is in an unoperated state; a bidirectional electronic AC device having two main terminals and a gating terminal for initiating conduction between said main terminals in both directions; means connecting said main terminals across the AC power source, one of said terminals being connected between said selectively operable means and the AC power source; means connecting said gating terminal and one of said main terminals across said load for initiating conduction of said electronic AC device; and means responsive to the conduction of said device for operating said precluding means to apply power from said source to said load.

Claim 6

In a circuit interconnecting a source of AC power and a load as set forth in claim 3: said selectively operable means is a pair of normally open contacts; and said means for operating said selectively operable means is a relay.

Claim 7

In a circuit interconnecting a source of AC power and a load as set forth in claim 3, wherein: said selectively operable means includes: normally disabled switching means; and a second bidirectional electronic A.C. device.

Claim 8

In a circuit interconnecting a source of AC power and a load as set forth in claim 5, wherein: said bidirectional electronic device is a first triac; and said second bidirectional electronic device is a second triac having main current-conducting terminals connected serially with said normally disabled means and having a gating terminal connected to said initiating means.

Claim 9

In a circuit interconnecting a source of AC power and a load as set forth in claim 6, wherein: said normally disabled switching means are normally open contacts; and said operating means is a relay which is energized by the conduction of said first triac for closing said normally open contacts and for opening said contacts when said first triac is rendered nonconductive.

Claim 10

In a load sensing and power application circuit interconnected between a source of AC power and an electrical load: a bidirectional switching device having two main current-carrying terminals interconnected by a normally disabled path through the load which is enabled by the application of a triggering potential to a third control electrode; means for connecting the main current carrying terminals across the source of A.C. power; a bias circuit connected across said load for applying triggering potential to the control electrode to enable the path and initiate operation of the device; a relay having normally open contacts interposed between the power source and the load; and means connecting said relay to said device for operating said relay to close said contacts to apply power from the source to the load.

Claim 11

In a load sensing and power application circuit interconnected between a source of AC power and an electrical load: a bidirectional switching device having two main current-carrying terminals interconnected by a normally disabled path through the load which is enabled by the application of a triggering potential to a third control electrode; means for connecting the main current carrying terminals across the source of A.C. power; a bias circuit connected across said load for applying triggering potential to the control electrode to enable the path and initiate operation of the device; a relay having normally open contacts interposed between the power source and the load; and means connecting said relay to said device for operating said relay to close said contacts to apply power from the source to the load.

Claim 12

An electrical circuit for sensing a load connected to output terminals and for supplying power from a source to said terminals which comprises: thyratron-like switching means having a control electrode and normally exhibiting a high impedance between two main current carrying terminals and exhibiting low impedance between said terminals upon application of a control signal to said control electrode; means for connecting said two main terminals in a current-carrying path to said load and said source; normally open means interposed between said source and said switching means for interrupting said current-carrying path; means including the load for applying operating potential to one of said main terminals and applying control signals to said control electrode; and means responsive to the presence of the load for closing said interrupting means to apply operating potential to the other of said main terminals to complete said current path to said load.

Claim 13

An electrical circuit for sensing a load connected to output terminals and for supplying power from a source to said terminals which comprises: thyratron-like switching means having a control electrode and normally exhibiting a high impedance between two main current carrying terminals and exhibiting low impedance between said terminals upon application of a control signal to said control electrode; means for connecting said two main terminals in a current-carrying path to said load and said source; normally open means interposed between said source and said switching means for interrupting said current-carrying path; means including the load for applying operating potential to one of said main terminals and applying control signals to said control electrode; and means responsive to the presence of the load for closing said interrupting means to apply operating potential to the other of said main terminals to complete said current path to said load.

Claim 14

In a circuit for supplying alternating current from a source to a load which is connected across a pair of spaced terminals: a relay having normally open contacts interposed between the soUrce and the load; a bidirectional current conducting semiconductor device normally exhibiting a high impedance characteristic between two main current-carrying terminals thereof and exhibiting a low-impedance characteristic in response to the application of a control signal to a third, gating terminal thereof and the application of opposite voltages to the main terminals, one of said main terminals connected to said normally open contacts and the other of said main terminals connected to said load; means connected from the gating terminal through the load to the source for applying a biasing potential to the gating terminal and an operating potential to said other of said terminals connected to said load; and means for energizing said relay to close said contacts to apply potential to the one main terminal and operate the semiconductor device to supply power to said load.

Claim 15

In a circuit for supplying alternating current from a source to a load which is connected across a pair of spaced terminals: a relay having normally open contacts interposed between the soUrce and the load; a bidirectional current conducting semiconductor device normally exhibiting a high impedance characteristic between two main current-carrying terminals thereof and exhibiting a low-impedance characteristic in response to the application of a control signal to a third, gating terminal thereof and the application of opposite voltages to the main terminals, one of said main terminals connected to said normally open contacts and the other of said main terminals connected to said load; means connected from the gating terminal through the load to the source for applying a biasing potential to the gating terminal and an operating potential to said other of said terminals connected to said load; and means for energizing said relay to close said contacts to apply potential to the one main terminal and operate the semiconductor device to supply power to said load.

Claim 16

In a circuit for applying AC power from a source to a load: a first triac having a gating terminal and main terminals interconnected between the AC power and the load; a normally open contact interposed between the AC power source and one of said main terminals; means for applying conditioning potential through the load to the gating terminal; a second triac having a gating terminal and main terminals connected across the source with the gating terminal of the second triac connected to receive operating potential through the load, to render said second triac conductive; and a relay coil energized by said second triac for closing said open contact to render said first triac conductive to apply said AC power to said load.

Claim 17

In a circuit for applying AC power from a source to a load: a first triac having a gating terminal and main terminals interconnected between the AC power and the load; a normally open contact interposed between the AC power source and one of said main terminals; means for applying conditioning potential through the load to the gating terminal; a second triac having a gating terminal and main terminals connected across the source with the gating terminal of the second triac connected to receive operating potential through the load, to render said second triac conductive; and a relay coil energized by said second triac for closing said open contact to render said first triac conductive to apply said AC power to said load.

Claim 18

In a circuit for applying a voltage from a source of alternating current power to a load: a bidirectional current conducting semiconductor device normally nonconductive between two main current-carrying terminals thereof and rendered conductive between the two main terminals in response to the application of a control signal to a gating terminal thereof; means for connecting said two terminals in a first current-carrying path to said source; a second current-conducting path for supplying power to the load; normally unoperated switching means in said second current-conducting path for conducting current from the source to the load; a relay in said first current-carrying path and having normally open contacts interposed in said second current-conducting path between the power source and the load; and means for applying a control signal to the gating terminal to render said first device conductive to energize said relay and close said contacts to operate said switching means and complete said second conducting path from the source to the load.

Claim 19

In a circuit for applying a voltage from a source of alternating current power to a load: a bidirectional current conducting semiconductor device normally nonconductive between two main current-carrying terminals thereof and rendered conductive between the two main terminals in response to the application of a control signal to a gating terminal thereof; means for connecting said two terminals in a first current-carrying path to said source; a second current-conducting path for supplying power to the load; normally unoperated switching means in said second current-conducting path for conducting current from the source to the load; a relay in said first current-carrying path and having normally open contacts interposed in said second current-conducting path between the power source and the load; and means for applying a control signal to the gating terminal to render said first device conductive to energize said relay and close said contacts to operate said switching means and complete said second conducting path from the source to the load.

Claim 20

In an electrical circuit for sensing a load connected to output terminals and for supplying power from a source to said terminals when said load is connected thereto: circuit means for connecting said source to said load; a first triac having two main terminals connected in parallel with said load and a third, gating terminal connected in series with said load; a second triac in said circuit means and having two main terminals connected in series with said load and a gating terminal connected in series with the gating terminal of the first triac; normally unoperated switching means in said circuit; means applying a triggering current to said gating terminals of said first and second triacs for switching said first triac to a conductive state and for conditioning said circuit means for conductance; and means connected in series with said first triac and energized by said first triac for operating said normally unoperated switching means to operate said second triac and to complete said circuit means to said load.

Claim 21

In an electrical circuit for sensing a load connected to output terminals and for supplying power from a source to said terminals when said load is connected thereto: circuit means for connecting said source to said load; a first triac having two main terminals connected in parallel with said load and a third, gating terminal connected in series with said load; a second triac in said circuit means and having two main terminals connected in series with said load and a gating terminal connected in series with the gating terminal of the first triac; normally unoperated switching means in said circuit; means applying a triggering current to said gating terminals of said first and second triacs for switching said first triac to a conductive state and for conditioning said circuit means for conductance; and means connected in series with said first triac and energized by said first triac for operating said normally unoperated switching means to operate said second triac and to complete said circuit means to said load.

Claim 22

In an electrical circuit for sensing a load connected to output terminals and for supplying power to said terminals when said load is connected thereto: first thyratron-like switching means having a cOntrol electrode, and a normally disabled transconductive path which is enabled by energizing the control electrode; means for connecting said source to said load which includes: second thyratron-like switching means identical to said first-switching means; and normally open means interposed between said source and load; means connected through the load for energizing said control electrodes to enable the path in the second-switching means and condition the connecting means for conductance; and means responsive to the enabling of the path in the first-switching device for closing said normally open means to complete said connecting means.

Claim 23

In an electrical circuit for sensing a load connected to output terminals and for supplying power to said terminals when said load is connected thereto: first thyratron-like switching means having a cOntrol electrode, and a normally disabled transconductive path which is enabled by energizing the control electrode; means for connecting said source to said load which includes: second thyratron-like switching means identical to said first-switching means; and normally open means interposed between said source and load; means connected through the load for energizing said control electrodes to enable the path in the second-switching means and condition the connecting means for conductance; and means responsive to the enabling of the path in the first-switching device for closing said normally open means to complete said connecting means.

Claim 24

In a system for sensing a load connected to output terminals and for then applying alternating current power from a source to the load: normally unconditioned circuit means for connecting said source to said load, including: a first AC switching device having a gating terminal and a normally disabled transconductive path between two main terminals which is enabled for conductance by applying a triggering current of either polarity to the gating terminal and a potential across the main terminals; and first normally open means interposed between said source and one of said main terminals; second normally open means interposed between said load and said source; and circuit means connected to said source for sensing a load connected to the output terminals and for completing said normally unconditioned circuit means, which includes: a second AC switching device having a gating terminal serially connected with the gating terminal of the first-switching means for normally applying potential from the source across the two main terminals thereof; means energized by said second-switching device for closing said normally open means; and means responsive to the connection of a load to the output terminals for applying potential to said gating terminals to condition said normally unconditioned circuit means and to operate said second-switching device to energize said closing means and close said normally open means to operate said first-switching device and complete said now conditioned circuit means.

Claim 25

In a system for sensing a load connected to output terminals and for then applying alternating current power from a source to the load: normally unconditioned circuit means for connecting said source to said load, including: a first AC switching device having a gating terminal and a normally disabled transconductive path between two main terminals which is enabled for conductance by applying a triggering current of either polarity to the gating terminal and a potential across the main terminals; and first normally open means interposed between said source and one of said main terminals; second normally open means interposed between said load and said source; and circuit means connected to said source for sensing a load connected to the output terminals and for completing said normally unconditioned circuit means, which includes: a second AC switching device having a gating terminal serially connected with the gating terminal of the first-switching means for normally applying potential from the source across the two main terminals thereof; means energized by said second-switching device for closing said normally open means; and means responsive to the connection of a load to the output terminals for applying potential to said gating terminals to condition said normally unconditioned circuit means and to operate said second-switching device to energize said closing means and close said normally open means to operate said first-switching device and complete said now conditioned circuit means.

Claim 26

In an electrical circuit for sensing a load connected to output terminals and for supplying power from an AC source to said terminals: a first bidirectional current conducting semiconductor device normally exhibiting a high impedance disabled path between two main current-carrying terminals and a low-impedance characteristic to enable said disabled path in response to the application of a control signal to a third gating terminal thereof, the minimum value of said signal being the same for both directions of current between said two terminals; means for connecting said two main terminals of said first semiconductor device in a current-carrying path to said source; a normally unconditioned circuit between said load and said source which includes: a second bidirectional current-conducting semiconductor device identical to said first semiconductor device with the gating terminal of said second device connected in series with the gating terminal of said first device and the two main terminals of the second device connected in said normally unconditioned circuit from the source to the load; normally open means interposed between said source and said second semiconductor device; means for applying a control signal to said gating terminals to enable said paths and condition said circuit between said source and said load for applying power to the load; and means responsive to the enabling of said path through said first semiconductor device for closing said normally open means to complete the conditioned circuit to supply power to the load.

Claim 27

In an electrical circuit for sensing a load connected to output terminals and for supplying power from an AC source to said terminals: a first bidirectional current conducting semiconductor device normally exhibiting a high impedance disabled path between two main current-carrying terminals and a low-impedance characteristic to enable said disabled path in response to the application of a control signal to a third gating terminal thereof, the minimum value of said signal being the same for both directions of current between said two terminals; means for connecting said two main terminals of said first semiconductor device in a current-carrying path to said source; a normally unconditioned circuit between said load and said source which includes: a second bidirectional current-conducting semiconductor device identical to said first semiconductor device with the gating terminal of said second device connected in series with the gating terminal of said first device and the two main terminals of the second device connected in said normally unconditioned circuit from the source to the load; normally open means interposed between said source and said second semiconductor device; means for applying a control signal to said gating terminals to enable said paths and condition said circuit between said source and said load for applying power to the load; and means responsive to the enabling of said path through said first semiconductor device for closing said normally open means to complete the conditioned circuit to supply power to the load.