Electric circuit for sequentially operating a plurality of ac loads

Claim 2

An electric circuit for operating AC loads sequentially wherein a plurality of loads are sequentially energized and then deenergized substantially simultaneously after said loads are all energized, comprising in combination: a plurality of stages each comprising at least a transistor; a time constant circuit including a capacitor; means connecting said transistor to said capacitor to control charging thereof; a Zener diode; a controlled rectifier element connected to a corresponding one of said loads; means connecting said capacitor to a gate of said controlled rectifier element through said Zener diode for causing Zener current to flow through said Zener diode to said gate of said controlled rectifier element when the voltage across said capacitor of said time constant circuit is raised to exceed the Zener voltage in a time predetermined by the time constant of said circuit whereby said controlled rectifier element is turned on, thereby energizing the load.

Claim 3

An electric circuit for operating a plurality of AC loads sequentially from an AC power source, comprising in combination: a plurality of stages each comprising a bridge rectifier circuit, a load connected at one of terminals thereof to one of terminals of the power source and at other terminal to one of AC sides of said bridge rectifier circuit, the other AC side of said bridge rectifier circuit being connecTed to the other terminal of the source, a SCR connected between the DC sides of said bridge rectifier circuit, said SCR turning on to shunt the DC side so as to energize the load, said SCR being controlled by a transistor circuit including a transistor which transistor circuit flows current to a gate of said SCR after said transistor of said circuit becomes nonconductive, means interconnecting said transistor circuits of said stages with respectively preceding stages for energizing said plurality of AC loads sequentially and for biasing said transistors of respective stages conductive to turn off the SCR''s of said stages after said plurality of AC loads are all energized.

Claim 4

An electric circuit for operating a plurality of AC loads sequentially from an AC power source, comprising in combination: a plurality of stages each comprising a bridge rectifier circuit, a load connected at one of terminals thereof to one of terminals of the power source and at other terminal to one of AC sides of said bridge rectifier circuit, the other AC side of said bridge rectifier circuit being connecTed to the other terminal of the source, a SCR connected between the DC sides of said bridge rectifier circuit, said SCR turning on to shunt the DC side so as to energize the load, said SCR being controlled by a transistor circuit including a transistor which transistor circuit flows current to a gate of said SCR after said transistor of said circuit becomes nonconductive, means interconnecting said transistor circuits of said stages with respectively preceding stages for energizing said plurality of AC loads sequentially and for biasing said transistors of respective stages conductive to turn off the SCR''s of said stages after said plurality of AC loads are all energized.

Claim 5

An electric circuit for operating a plurality of AC loads sequentially from an AC power source, comprising in combination: a plurality of stages each comprising a triac, an AC load connected at one terminal thereof to one of terminals of the power source and at the other terminal to an anode of said triac, and a transistor circuit connected to a gate of said triac and including a Zener diode and a time constant circuit including a capacitor, said capacitor supplying gate current to the triac from the capacitor to energize the corresponding load at a certain time interval after the load of preceding stage is energized, and cuts off the gate current of the triac to deenergize the corresponding load substantially simultaneously when the load of preceding stage is deenergized; and another stage and means connecting same to the transistor circuit of the first of said plurality of stages, for rendering the triac of first stage turned off so as not to flow current to the load only for a period of time while charging of said capacitor of said time constant circuit is being effected after the load of last stage of said plurality of stages becomes deenergized.

Claim 6

An electric circuit for operating a plurality of AC loads sequentially from an AC power source, comprising in combination: a plurality of stages each comprising a triac, an AC load connected at one terminal thereof to one of terminals of the power source and at the other terminal to an anode of said triac, and a transistor circuit connected to a gate of said triac and including a Zener diode and a time constant circuit including a capacitor, said capacitor supplying gate current to the triac from the capacitor to energize the corresponding load at a certain time interval after the load of preceding stage is energized, and cuts off the gate current of the triac to deenergize the corresponding load substantially simultaneously when the load of preceding stage is deenergized; and another stage and means connecting same to the transistor circuit of the first of said plurality of stages, for rendering the triac of first stage turned off so as not to flow current to the load only for a period of time while charging of said capacitor of said time constant circuit is being effected after the load of last stage of said plurality of stages becomes deenergized.

Claim 7

An electric circuit for operating a plurality of AC loads sequentially, comprising in combination: a plurality of stages and a control circuit; said plurality of stages each including an AC load connected at one terminal thereof to one terminal of a power source and at the other terminal to one of the AC sides of a bridge rectifier circuit, a transformer having a primary side connected across said AC load and a secondary side, a time constant circuit including a capacitor, a Zener diode, a transistor adapted to be biased conductive by said capacitor through said Zener diode, an SCR and means connecting said SCR and transistor for causing said SCR to energize the load upon said transistor becoming conductive, said time constant circuit, transistor and SCR of at least one of said stages being connected to said secondary side of said transformer of a prior stage; said control circuit including a further transformer connected to said plurality of stages for causing all capacitors of said time constant circuits of said plurality of stages to discharge to bias said transistor of each thereof nonconductive, so that the corresponding SCR thereof is turned off, thereby deenergizing of said loads.

Claim 8

An electric circuit for operating a plurality of AC loads sequentially, comprising in combination: a plurality of stages and a control circuit; said plurality of stages each including an AC load connected at one terminal thereof to one terminal of a power source and at the other terminal to one of the AC sides of a bridge rectifier circuit, a transformer having a primary side connected across said AC load and a secondary side, a time constant circuit including a capacitor, a Zener diode, a transistor adapted to be biased conductive by said capacitor through said Zener diode, an SCR and means connecting said SCR and transistor for causing said SCR to energize the load upon said transistor becoming conductive, said time constant circuit, transistor and SCR of at least one of said stages being connected to said secondary side of said transformer of a prior stage; said control circuit including a further transformer connected to said plurality of stages for causing all capacitors of said time constant circuits of said plurality of stages to discharge to bias said transistor of each thereof nonconductive, so that the corresponding SCR thereof is turned off, thereby deenergizing of said loads.

Claim 9

An electric circuit for operating plural AC loads sequentially wherein said plurality of AC loads are energized in sequence and deenergized substantially simultaneously, comprising in combination: a plurality of stages each including an AC load and a triac in series connection with each other and connected in parallel with respect to an AC power source, each stage having a time constant circuit and a Zener diode and a transistor circuit including transistors, means connecting one of said transistors to said time constant circuit through said Zener diode for rendering said one transistor conductive through said time constant circuit and Zener diode when a further transistor of the preceding stage becomes nonconductive, said one transistors of said stages being connected to the gates of the corresponding ones of said triacs; each of said triacs being triggered by said one transistor irrespective of operation of the triac of preceding stage and thereby energizing the corresponding load.

Claim 10

An electric circuit for operating plural AC loads sequentially wherein said plurality of AC loads are energized in sequence and deenergized substantially simultaneously, comprising in combination: a plurality of stages each including an AC load and a triac in series connection with each other and connected in parallel with respect to an AC power source, each stage having a time constant circuit and a Zener diode and a transistor circuit including transistors, means connecting one of said transistors to said time constant circuit through said Zener diode for rendering said one transistor conductive through said time constant circuit and Zener diode when a further transistor of the preceding stage becomes nonconductive, said one transistors of said stages being connected to the gates of the corresponding ones of said triacs; each of said triacs being triggered by said one transistor irrespective of operation of the triac of preceding stage and thereby energizing the corresponding load.

Claim 11

The circuit of claim 1 in which each of said stages includes a bridge rectifier having a pair of AC terminals and a pair of DC terminals, an AC source in series loop with the AC load associated with each of said stages and with the AC terminals of the bridge rectifier of each of said stages, means connecting the controlled rectifier of each said stage across the DC terminals of the corresponding bridge rectifier for energizing said load through said bridge rectifier upon conduction of said SCR, a transformer in each said stage, means connecting the input side of each said transformer to said DC terminals of the bridge rectifier circuit of the corresponding stage for allowing current flow through said transformer from said AC source at a level less than that required to energize the corresponding load and while the corresponding SCR is nonconductive, means connecting the output side of each said transformer to the transistor the next stage for energizing said transistors, said transistors being connected to the corresponding ones of said capacitors for controlling charging thereof.

Claim 12

The circuit of claim 2 including a further stage in addition to said plurality of stages, said further stage including a further transistor circuit having time delay means, means coupling said transistor circuit to the SCR of the last energized one of said plurality of stages at the input side of said further transistor circuit, means coupling the output side of said further transistor circuit to the transistor circuit of the first energized one of said plurality of stages for rendering said first energized one of said stages deenergized at a fixed time interval after energization of the last energized one of said stages and means interconnecting said stages for substantially immediately turning off the SCRs thereof upon turning off of the SCR of said first energized stage.

Claim 13

The circuit of claim 3 in which said transistor circuit of at least one of said plurality of stages includes a first transistor and means connecting same to the triac of the preceding stage and to said capacitor of said one stage for permitting charging of said said capacitor in response to the conduction of said triac of said preceding stage through the load of said preceding stage and a second transistor connected from the gate of the triac of said one stage through said Zener diode to said capacitor of said one stage for rendering said triac conductive through the load of said one stage after said capacitor of said one stage has achieved a preselected level of change.

Claim 14

The circuit of claim 3 in which the transistor circuit of each of said plurality of stages includes a first transistor connected to the gate of the corresponding triac for holding said triac nonconductive when said first transistor is conductive, means coupling said capacitor to said first transistor for rendering said first transistor nonconductive after a time delay, means in each of said stages except the first energized stage for charging said capacitor thereof in response to conduction of the triac of the preceding stage, said another stage including a second transistor and means connecting same to the triac of the last energized stage of said plurality of stages for rendering said second transistor nonconductive upon conduction of said last-mentioned triac, said another stage including a further capacitor and means coupling same to said second transistor for charging thereof upon nonconduction of said second transistor to effect a time delay after energization of said load of said last energized stage of said plurality of stages and means rendering said first transistor of said first energized stage conductive to turn off said triac of said first energized stage upon charging to a preselected level of said second capacitor whereby to effect a delay in deenergization of said load of said first energized stage after energizatIon of the load of the last energized stage, said another stage including a third transistor responsive to conduction of said second transistor for turning off, and means connecting said third transistor to said capacitor of said first stage for preventing charging thereof to a level sufficient to cause energization of said triac of said first energized stage when said third transistor is conductive.

Claim 15

The circuit of claim 4 in which said control circuit includes a further transistor and clamping means connecting same to said capacitors of said plurality of stages for clamping same in a discharged condition in response to conduction of said further transistor so that the transistor of said plurality of stages are switched to deenergize the loads thereof, said control circuit including a further capacitor and means connecting same to said further transistor for rendering same conductive after a delay starting with the energization of the load of the last of said plurality of stages.