Surge suppression for low voltage signal circuits

Claim 2

A voltage surge suppression circuit for protecting a low voltage signal circuit which receives data or signals from a coaxial cable which comprises a signal conductor and a ground shield conductor, said circuit comprising a gas tube connected across the signal and shield conductors of the cable and an MOV connecting the shield conductor of the cable to a ground.

Claim 3

The circuit of claim 1 wherein said MOV connects said shield conductor to a ground line of a power line voltage surge suppression means.

Claim 4

The coaxial cable surge suppression circuit of claim 2 wherein said power line voltage suppression means includes a line conductor, a neutral conductor and a ground conductor, along with a line voltage surge suppression circuit comprising: a first metal oxide varistor having a first terminal connected to said line conductor and a second terminal; a power interrupter comprising a temperature sensitive power cut off switch which is normally closed and which opens when the temperature of said switch is raised to a predetermined level for interrupting current therethrough when said current exceeds a predetermined limit, said interrupter having a first terminal connected to said second terminal of said first metal oxide varistor and a second terminal of said power interrupter connected to said neutral conductor, and a second metal oxide varistor having a first terminal connected to said second terminal of said first metal oxide varistor and a second terminal of said second metal oxide varistor connected to said ground conductor.

Claim 5

The invention of claim 3 wherein said temperature of said power interrupter is raised to said predetermined level by heat transfer from either of said metal oxide varistors.

Claim 6

The invention of claim 4 wherein said power cut off switch is in heat exchange relationship with both of said metal oxide varistors.

Claim 7

The invention of claim 5 wherein said first metal oxide varistor is disposed adjacent said cut-off switch such that the surface of said first metal oxide varistor adjacent the outer surface of said cut-off switch is spaced from said outer surface of said power cut-off switch a distance of not greater than 0.03 inch.

Claim 8

The invention of claim 6 wherein said second metal oxide varistor is disposed adjacent said cut-off switch such that the surface of said second metal oxide varistor adjacent the outer surface of said cut-off switch is spaced a distance of not greater than 0.03 inch from said outer surface of said cut-off switch.

Claim 9

The invention of claim 7 having indicator means for indicating the condition of said first and second metal oxide varistors, said indicator means having a first terminal connected to the junction of said second terminal of said first metal oxide varistor and said first terminal of said second metal oxide varistor and a second terminal of said indicator means connected to said line conductor.

Claim 10

A voltage surge suppression circuit for a low-voltage coaxial cable comprising a signal conductor and a ground shield conductor, said circuit comprising a gas tube connected across the signal and shield conductors and an MOV connecting the shield conductor to a ground.

Claim 11

A voltage surge suppression circuit for a low-voltage coaxial cable comprising a signal conductor and a ground shield conductor, said circuit comprising a gas tube connected across the signal and shield conductors and an MOV connecting the shield conductor to a ground.

Claim 12

The circuit of claim 9 wherein said MOV connects said shield conductor to a ground line of a power line voltage surge suppression means.

Claim 13

The coaxial cable surge suppression circuit of claim 10 wherein said power line voltage surge suppression means includes a line conductor, a neutral conductor and a ground conductor along with a line voltage surge suppression circuit comprising: (i) a first metal oxide varistor having a first and second terminal, said first terminal connected to said line conductor; (ii) a second metal oxide varistor having a first and second terminal, wherein said first terminal thereof is connected to said second terminal of said first metal oxide varistor and wherein said second terminal is connected to said ground conductor, and (iii) a temperature sensitive power cut-off switch for interrupting current through said surge suppression circuit when said current exceeds a predetermined level, said switch having a first terminal connected to said second terminal of said first metal oxide varistor and a second terminal connected to said neutral conductor, said switch being normally closed and which opens when the temperature of said switch is raised to a predetermined level by heat transfer from either of said metal oxide varistors which heat up when the current therethrough exceeds said predetermined level.

Claim 14

The circuit of claim 11 wherein said power cut-off switch is in heat exchange relationship with both of said metal oxide varistors of said power line voltage surge suppression circuit.

Claim 15

The circuit of claim 12 wherein both of said metal oxide varistors of said line voltage surge suppression circuit are disposed adjacent said power cut-off switch such that the surface of said varistors adjacent the outer surface of said switch is spaced apart therefrom at a distance not exceeding 0.03 inches.

Claim 16

The circuit of claim 13 wherein said line voltage surge suppression circuit further contains indicator means for indicating the condition of said first and second metal oxide varistors, said indicator means having a first and a second terminal, wherein said first terminal is connected to the junction of said second terminal of said first metal oxide varistor and said first terminal of said second metal oxide varistor and wherein said second terminal of said indicator means is connected to said line conductor.

Claim 17

A voltage surge suppression circuit for a two conductor, low-voltage balanced signal line, said circuit comprising a firs gas tube connected across both of said conductors and a second gas tube connecting one of said conductors to a ground line of a power line voltage surge suppression means, wherein said power line voltage surge suppression means includes a line conductor, a neutral conductor and a ground conductor along with a power line voltage surge suppression circuit comprising: (i) a first metal oxide varistor having a first and second terminal, said first terminal connected to said line conductor; (ii) a second metal oxide varistor having a first and second terminal, wherein said first terminal thereof is connected to said second terminal of said first metal oxide varistor and wherein said second terminal is connected to said ground conductor, and (iii) a temperature sensitive power cut-off switch for interrupting current through said surge suppression circuit when said current exceeds a predetermined level, said switch having a first terminal connected to said second terminal of said first metal oxide varistor and a second terminal connected to said neutral conductor, said switch being normally closed and which opens when the temperature of said switch is raised to a predetermined level by heat transfer from either of said metal oxide varistors which heat up when the current therethrough exceeds said predetermined level.

Claim 18

A voltage surge suppression circuit for a two conductor, low-voltage balanced signal line, said circuit comprising a firs gas tube connected across both of said conductors and a second gas tube connecting one of said conductors to a ground line of a power line voltage surge suppression means, wherein said power line voltage surge suppression means includes a line conductor, a neutral conductor and a ground conductor along with a power line voltage surge suppression circuit comprising: (i) a first metal oxide varistor having a first and second terminal, said first terminal connected to said line conductor; (ii) a second metal oxide varistor having a first and second terminal, wherein said first terminal thereof is connected to said second terminal of said first metal oxide varistor and wherein said second terminal is connected to said ground conductor, and (iii) a temperature sensitive power cut-off switch for interrupting current through said surge suppression circuit when said current exceeds a predetermined level, said switch having a first terminal connected to said second terminal of said first metal oxide varistor and a second terminal connected to said neutral conductor, said switch being normally closed and which opens when the temperature of said switch is raised to a predetermined level by heat transfer from either of said metal oxide varistors which heat up when the current therethrough exceeds said predetermined level.

Claim 19

The circuit of claim 15 wherein said power cut-off switch is in heat exchange relationship with both of said metal oxide varistors of said power line voltage surge suppression circuit.

Claim 20

The circuit of claim 16 wherein both of said metal oxide varistors of said line voltage surge suppression circuit are disposed adjacent said power cut-off switch such that the surface of said varistors adjacent the outer surface of said switch is spaced apart therefrom at a distance not exceeding 0.03 inches.

Claim 21

The circuit of claim 17 wherein said line voltage surge suppression circuit further contains indicator means for indicating the condition of said first and second metal oxide varistors, said indicator means having a first and a second terminal, wherein said first terminal is connected to the junction of said second terminal of said first metal oxide varistor and said first terminal of said second metal oxide varistor and wherein said second terminal of said indicator means is connected to said line conductor.

Claim 22

A voltage surge suppression circuit for a two conductor, low-voltage balanced signal line, said circuit comprising a first gas tube connected across both of said conductors, a second gas tube connecting one of said conductors to a ground and a third gas tube connecting the other end of said conductors to a ground, wherein said ground is a ground line of a power line voltage surge suppression means and wherein said power line voltage surge suppression means includes a line conductor, a neutral conductor and a ground conductor along with a power line voltage surge suppression circuit comprising: (i) a first metal oxide varistor having a first and second terminal, said first terminal connected to said line conductor; (ii) a second metal oxide varistor having a first and second terminal, wherein said first terminal thereof is connected to said second terminal of said first metal oxide varistor and wherein said second terminal is connected to said ground conductor, and (iii) a temperature sensitive power cut-off switch for interrupting current through said surge suppression circuit when said current exceeds a predetermined level, said switch having a first terminal connected to said second terminal of said first metal oxide varistor and a second terminal connected to said neutral conductor, said switch being normally closed and which opens when the temperature of said switch is raised to a predetermined level by heat transfer from either of said metal oxide varistors which heat up when the current therethrough exceeds said predetermined level.

Claim 23

A voltage surge suppression circuit for a two conductor, low-voltage balanced signal line, said circuit comprising a first gas tube connected across both of said conductors, a second gas tube connecting one of said conductors to a ground and a third gas tube connecting the other end of said conductors to a ground, wherein said ground is a ground line of a power line voltage surge suppression means and wherein said power line voltage surge suppression means includes a line conductor, a neutral conductor and a ground conductor along with a power line voltage surge suppression circuit comprising: (i) a first metal oxide varistor having a first and second terminal, said first terminal connected to said line conductor; (ii) a second metal oxide varistor having a first and second terminal, wherein said first terminal thereof is connected to said second terminal of said first metal oxide varistor and wherein said second terminal is connected to said ground conductor, and (iii) a temperature sensitive power cut-off switch for interrupting current through said surge suppression circuit when said current exceeds a predetermined level, said switch having a first terminal connected to said second terminal of said first metal oxide varistor and a second terminal connected to said neutral conductor, said switch being normally closed and which opens when the temperature of said switch is raised to a predetermined level by heat transfer from either of said metal oxide varistors which heat up when the current therethrough exceeds said predetermined level.