Hybrid relay circuit having electromagnetic relay for switching AC power supply

Claim 2

A hybrid relay circuit for supplying current to a load with a AC power supply in accordance with an input signal, comprising: an electromagnetic relay having a contact connected in series to said load and said AC power supply; a driving circuit, connected to said electromagnetic relay, for driving said electromagnetic relay in accordance with said input control signal; a detection circuit, connected to said AC power supply, for detecting whether the potential of said AC power supply is zero, said detection circuit comprising a rectifier bridge circuit having two pairs of diagonal terminals, one pair of said diagonal terminals being connected to the terminals of said AC power supply, a photocoupler connected to the other pair of diagonal terminals, and a differential circuit linked between said photocoupler and said driving circuit; an opening timing control circuit linked between said detection circuit and said driving circuit, for turning ON said driving circuit after receiving said input control signal which is turned OFF, so that said contact is opened when the potential of said AC power supply becomes approximately zero wherein said opening timing control circuit comprises a first hold circuit, connected to said detection circuit, for holding the output of said detection circuit after said detection circuit detects that the potential of said AC power supply is zero, and a first integration circuit, linked between said first hold circuit and said driving circuit, for delaying the output of said first hold circuit, thereby turning OFF said driving circuit, said first hold circuit being operated when said input control signal is turned OFF; and a DC buffer for receiving said input control signal and applying a DC voltage to said first hold circuit and to said electromagnetic relay.

Claim 3

A circuit as set forth above in claim 1, further comprising a closing timing control circuit, linked between said detection circuit and said driving circuit, for turning ON said driving circuit after receiving said input control signal which is turned ON, so that said contact is closed when the potential of said AC power supply becomes approximately zero.

Claim 4

A circuit as set forth in claim 2, wherein said closing timing control circuit comprises: a second circuit, connected to said detection circuit, for holding the output of said detection circuit after said detection circuit detects that the potential of said AC power supply is zero; and a second integration circuit, linked between said second hold circuit and said driving circuit, for delaying the output of said second hold circuit, thereby turning ON said driving circuit, said second holding circuit being operated when said input control signal is turned ON.

Claim 5

A circuit as set forth in claim 3, wherein said DC buffer applies said DC voltage to said second hold circuit, and to said second integration circuit.

Claim 6

A circuit as set forth in claim 1, wherein said contact is a make contact.

Claim 7

A circuit as set forth in claim 1, wherein said contact is a transfer contact therein switching the connection of a plurality of loads to said AC power supply in accordance with said input control signal.

Claim 8

A hybrid relay circuit for supplying current to a load with a AC power supply in accordance with an input signal, comprising: an electromagnetic relay having a contact connected in series to said load and said AC power supply; a driving circuit, connected to said electromagnetic relay, for driving said electromagnetic relay in accordance with said input control signal; a detection circuit, connected to said AC power supply, for detecting whether the potential of said AC power supply is zero, said detection circuit comprising a rectifier bridge circuit having two pairs of diagonal terminals, one pair of said diagonal terminals being connected to the terminals of said AC power supply, a photocoupler connected to the other pair of diagonal terminals, and a differential circuit linked between said photocoupler and said driving circuit; a closing timing control circuit, connected to said driving circuit, for turning ON said driving circuit after receiving said input control signal which is turned ON, so that said contact is closed when the potential of said AC power supply becomes approximately zero; and an opening timing control circuit, connected to said driving circuit, for turning ON said driving circuit after receiving said input control signal which is turned OFF, so that said contact is opened when the potential of AC power supply becomes approximately zero.

Claim 9

A hybrid relay circuit for supplying current to a load with a AC power supply in accordance with an input signal, comprising: an electromagnetic relay having a contact connected in series to said load and said AC power supply; a driving circuit, connected to said electromagnetic relay, for driving said electromagnetic relay in accordance with said input control signal; a detection circuit, connected to said AC power supply, for detecting whether the potential of said AC power supply is zero, said detection circuit comprising a rectifier bridge circuit having two pairs of diagonal terminals, one pair of said diagonal terminals being connected to the terminals of said AC power supply, a photocoupler connected to the other pair of diagonal terminals, and a differential circuit linked between said photocoupler and said driving circuit; a closing timing control circuit, connected to said driving circuit, for turning ON said driving circuit after receiving said input control signal which is turned ON, so that said contact is closed when the potential of said AC power supply becomes approximately zero; and an opening timing control circuit, connected to said driving circuit, for turning ON said driving circuit after receiving said input control signal which is turned OFF, so that said contact is opened when the potential of AC power supply becomes approximately zero.

Claim 10

A circuit as set forth in claim 7, further comprising a common detection circuit for said closing timing control circuit and said opening timing control circuit, said common detection circuit detecting whether the potential of said AC power supply is zero.

Claim 11

A circuit as set forth in claim 8, wherein said common detection circuit comprises: a rectifier bridge circuit having two pairs of diagonal terminals, one pair of said diagonal terminals being connected to said contact; a photocoupler connected to the other pair of diagonal terminals; and a differential circuit linked between said photocoupler and a hold circuit.

Claim 12

A circuit as set forth in claim 8, wherein said common detection circuit comprises: a current transformer connected to said AC power supply, said current transformer having first and second windings; a current limiting resistor associated with said second winding of said current transformer, linked between the terminals of said contact; a rectifier bridge circuit having two pairs of diagonal terminals, one pair of said diagonal terminals being connected to said first winding of said current transformer; and a resistor connected to the other pair of diagonal terminals of said rectifier bridge circuit.

Claim 13

A circuit as set forth in claim 8, wherein each of said closing and opening timing control circuits comprises: a hold circuit, connected to said common detection circuit, for holding the output of said common detection circuit after said common detection circuit detects that the potential of said AC power supply is zero; and an integration circuit, connected to said hold circuit and said driving circuit, for delaying the output of said hold circuit; said integration circuit of said closing timing control circuit being operated when said input control signal is turned ON, said hold circuit of said opening timing control circuit being operated when said input control signal is turned OFF.

Claim 14

A hybrid relay circuit for supplying current to a load with a AC power supply in accordance with an input control signal, comprising: an electromagnetic relay having a contact connected in series to said load and said AC power supply; a driving circuit, connected to said electromagnetic relay, for driving said electromagnetic relay in accordance with said input control signal; and a detection circuit, connected to said AC power supply, for detecting whether the potential of said AC power supply is zero, said detection circuit comprising a current transformer connected to said AC power supply, said current transformer having first and second windings, a current limiting resistor associated with said second winding of said current transformer, linked between the terminals of said contact, a rectifier bridge circuit having two pairs of diagonal terminals, one pair of said diagonal terminals being connected to said first winding of said current transformer, and a resistor connected to the other pair of diagonal terminals of said rectifier bridge circuits; an opening timing control circuit linked between said detection circuit and said driving circuit, for turning ON said driving circuit after receiving said input control signal which is turned OFF, so that said contact is opened when the potential of said AC power supply becomes aproximately zero wherein said opening timing control circuit comprises a first hold circuit, connected to said detection circuit, for holding the output of said detection circuit after said detection circuit detects that the potential of said AC power supply is zero, and a first integration circuit, linked between said first hold circuit and said driving circuit, for delaying the output of said first hold circuit, thereby turning OFF said driving circuit, said first hold circuit being operated when said input control signal is turned OFF a DC buffer for receiving said input control signal and applying a DC voltage to said first hold circuit and to said electromagnetic relay.

Claim 15

A hybrid relay circuit for supplying current to a load with a AC power supply in accordance with an input control signal, comprising: an electromagnetic relay having a contact connected in series to said load and said AC power supply; a driving circuit, connected to said electromagnetic relay, for driving said electromagnetic relay in accordance with said input control signal; and a detection circuit, connected to said AC power supply, for detecting whether the potential of said AC power supply is zero, said detection circuit comprising a current transformer connected to said AC power supply, said current transformer having first and second windings, a current limiting resistor associated with said second winding of said current transformer, linked between the terminals of said contact, a rectifier bridge circuit having two pairs of diagonal terminals, one pair of said diagonal terminals being connected to said first winding of said current transformer, and a resistor connected to the other pair of diagonal terminals of said rectifier bridge circuits; an opening timing control circuit linked between said detection circuit and said driving circuit, for turning ON said driving circuit after receiving said input control signal which is turned OFF, so that said contact is opened when the potential of said AC power supply becomes aproximately zero wherein said opening timing control circuit comprises a first hold circuit, connected to said detection circuit, for holding the output of said detection circuit after said detection circuit detects that the potential of said AC power supply is zero, and a first integration circuit, linked between said first hold circuit and said driving circuit, for delaying the output of said first hold circuit, thereby turning OFF said driving circuit, said first hold circuit being operated when said input control signal is turned OFF a DC buffer for receiving said input control signal and applying a DC voltage to said first hold circuit and to said electromagnetic relay.

Claim 16

A circuit as set forth above in claim 12, further comprising a closing timing control circuit, linked between said detection circuit and said driving circuit, for turning ON said driving circuit after receiving said input control signal which is turned ON, so that said contact is closed when the potential of said AC power supply becomes approximately zero.

Claim 17

A circuit as set forth in claim 13, wherein said closing timing control circuit comprises: a second hold circuit, connected to said detection circuit, for holding the output of said detection circuit after said detection circuit detects that the potential of said AC power supply is zero; and a second integration circuit, linked between said second hold circuit and said driving circuit, for delaying the output of said second hold circuit, thereby turning ON said driving circuit, said second holding circuit being operated when said input control signal is turned ON.

Claim 18

A circuit as set forth in claim 14, wherein said DC buffer applies said DC voltage to said second hold circuit, and to said second integration circuit.

Claim 19

A circuit as set forth in claim 12, wherein said contact is a make contact.

Claim 20

A circuit as set forth in claim 12, wherein said contact is a transfer contact therein switching the connection of a plurality of loads to said AC power supply in accordance with said input control signal.

Claim 21

A hybrid relay circuit for supplying current to a load with a AC power supply in accordance with an input control signal, comprising: an electromagnetic relay having a contact connected in series to said load and said AC power supply; a driving circuit, connected to said electromagnetic relay, for driving said electromagnetic relay in accordance with said input control signal; a detection circuit, connected to said AC power supply, for detecting whether the potential of said AC power supply is zero, said detection circuit comprising a current transformer connected to said AC power supply, said current transformer having first and second windings, a current limiting resistor associated with said second winding of said current transformer, linked between the terminals of said contact, a rectifier bridge circuit having two pairs of diagonal terminals, one pair of said diagonal terminals being connected to said first winding of said current transformer, and a resistor connected to the other pair of diagonal terminals of said rectifier bridge circuits; a closing timing control circuit, connected to said driving circuit, for turning ON said driving circuit after receiving said input control signal which is turned ON, so that said contact is closed when the potential of said AC power supply becomes approximately zero; and an opening timing control circuit, connected to said driving circuit, for turning ON said driving circuit after receiving said input control signal which is turned OFF, so that said contact is opened when the potential of AC power supply becomes approximately zero.

Claim 22

A hybrid relay circuit for supplying current to a load with a AC power supply in accordance with an input control signal, comprising: an electromagnetic relay having a contact connected in series to said load and said AC power supply; a driving circuit, connected to said electromagnetic relay, for driving said electromagnetic relay in accordance with said input control signal; a detection circuit, connected to said AC power supply, for detecting whether the potential of said AC power supply is zero, said detection circuit comprising a current transformer connected to said AC power supply, said current transformer having first and second windings, a current limiting resistor associated with said second winding of said current transformer, linked between the terminals of said contact, a rectifier bridge circuit having two pairs of diagonal terminals, one pair of said diagonal terminals being connected to said first winding of said current transformer, and a resistor connected to the other pair of diagonal terminals of said rectifier bridge circuits; a closing timing control circuit, connected to said driving circuit, for turning ON said driving circuit after receiving said input control signal which is turned ON, so that said contact is closed when the potential of said AC power supply becomes approximately zero; and an opening timing control circuit, connected to said driving circuit, for turning ON said driving circuit after receiving said input control signal which is turned OFF, so that said contact is opened when the potential of AC power supply becomes approximately zero.

Claim 23

A circuit as set forth in claim 18, further comprising a common detection circuit for said closing timing control circuit and said opening timing control circuit, said common detection circuit detecting whether the potential of said AC power supply is zero.

Claim 24

A circuit as set forth in claim 19, wherein said common detection circuit comprises: a rectifier bridge circuit having two pairs of diagonal terminals, one pair of said diagonal terminals being connected to said contact; a photocoupler connected to the other pair of diagonal terminals; and a differential circuit linked between said photocoupler and a hold circuit.

Claim 25

A circuit as set forth in claim 19, wherein said common detection circuit comprises: a current transformer connected to said AC power supply, said current transformer having first and second windings; a current limiting resistor associated with said second winding of said current transformer, linked between the terminals of said contact; a rectifier bridge circuit having two pairs of diagonal terminals, one pair of said diagonal terminals being connected to said first windings of said current transformer; and a resistor connected to the other pair of diagonal terminals of said rectifier bridge circuit.

Claim 26

A circuit as set forth in claim 19, wherein each of said closing and opening timing control circuits comprises: a hold circuit, connected to said common detection circuit, for holding the output of said common detection circuit after said common detection circuit detects that the potential of said AC power supply is zero; and an integration circuit, connected to said hold circuit and said driving circuit, for delaying the output of said hold circuit; said integration circuit of said closing timing control circuit being operated when said input control signal is turned ON, said hold circuit of said opening timing control circuit being operated when said input control signal is turned OFF.