Anti-cycling device for high pressure sodium lamps

Claim 2

An anti-cycling device, for cutting off the electrical power supplied to a malfunctioning high-pressure sodium lamp, and the like, wherein electrical power is supplied from a power source to said lamp by at least a pair of electrically conductive power supply wires, said device comprising: a current transformer, operatively connectable to at least one of said wires, said current transformer being characterized in that when it is operatively connected to said at least one wire, said current transformer develops an alternating low voltage output that varies generally proportionally to variations in the magnitude of the electric current in said at least one wire; a first operational amplifier responsively connected to said current transformer, and characterized in that said first amplifier outputs an amplified alternating voltage output signal whose magnitude is generally proportional to said voltage output of said current transformer; a second operational amplifier; a set-point diode interconnecting said first and second operational amplifiers, said set-point diode rectifying said first amplifier's alternating voltage output signal, and transmitting said rectified output signal to said second operational amplifier, wherein said second amplifier is characterized in that it is operative to compare said rectified signal with a certain preselected threshold signal, and to transmit a trigger signal every time said rectified signal exceeds said threshold signal; a counter, operatively connected to said second amplifier for receiving each trigger signal from the same, said counter being characterized in that it counts the number of transmissions of said trigger signal from said second amplifier during a given time period, and outputs a malfunction cut-off signal in the event such number exceeds a certain preselected number during such period; and a switch, connectable to at least one of said power supply wires, and connected to said counter in a manner such that said switch is operable to disconnect said lamp from said power source in response to the output of said malfunction cut-off signal from said counter.

Claim 3

The anti-cycling device of claim 1, including an indicator light connected to said counter in a manner such that said light obtains an activated condition in response to the output of said malfunction cut-off signal from said counter, said indicator light being positionable in a location relative to said high-pressure sodium lamp so as to be observable by a maintenance person.

Claim 4

The anti-cycling device of claim 1, including reset circuit means connected to said counter, for resetting the number of trigger signals counted by said counter to zero each day.

Claim 5

The anti-cycling device of claim 3, wherein said reset circuit means is further operable to reset the number of trigger signals counted by said counter to zero in response to electrical connection of said lamp to said power source.

Claim 6

The anti-cycling device of claim 1, including reset circuit means having a photodiode-isolated transistor, said photodiode-isolated transistor interconnecting said pair of electrically conductive power supply wires.

Claim 7

An anti-cycling device, for cutting off the electrical power supplied to a malfunctioning high-pressure sodium lamp, and the like, wherein electrical power is supplied from a power source to said lamp by at least a pair of electrically-conductive power supply wires, and a constant power ballast is serially positioned in one of said power supply wires, said device comprising: a current transformer, operatively connected to said one power supply wire between said constant power ballast and said lamp, said current transformer being characterized in that when it is operatively connected to said one power supply wire, said current transformer develops an alternating low voltage output that varies generally proportionally to variations in the magnitude of the electric current in said wire; a first operational amplifier responsively connected to said current transformer and characterized in that said first amplifier outputs an amplified alternating voltage output signal whose magnitude is generally proportional to said voltage output of said current transformer; a second operational amplifier; a set-point diode interconnecting said first and second operational amplifiers, said set-point diode rectifying said first amplifier's alternating voltage output signal, and transmitting said first amplifier's output signal to said second operational amplifier, wherein said second amplifier is characterized in that it is operative to compare said rectified signal with a certain preselected threshold signal, and to transmit a trigger signal every time said rectified signal exceeds said threshold signal; a counter, operatively connected to said second amplifier for receiving each trigger signal from the same, said counter being characterized in that it counts the number of transmissions of said trigger signal from said second amplifier during a given time period, and outputs a malfunction cut-off signal in the event such number exceeds a certain preselected number during such period; and a switch, connectable to at least one of said power supply wires, and connected to said counter in a manner such that said switch is operable to disconnect said lamp from said power source in response to the output of said malfunction cut-off signal from said counter.

Claim 8

An anti-cycling device, for cutting off the electrical power supplied to a malfunctioning high-pressure sodium lamp, and the like, wherein electrical power is supplied from a power source to said lamp by at least a pair of electrically-conductive power supply wires, and a constant power ballast is serially positioned in one of said power supply wires, said device comprising: a current transformer, operatively connected to said one power supply wire between said constant power ballast and said lamp, said current transformer being characterized in that when it is operatively connected to said one power supply wire, said current transformer develops an alternating low voltage output that varies generally proportionally to variations in the magnitude of the electric current in said wire; a first operational amplifier responsively connected to said current transformer and characterized in that said first amplifier outputs an amplified alternating voltage output signal whose magnitude is generally proportional to said voltage output of said current transformer; a second operational amplifier; a set-point diode interconnecting said first and second operational amplifiers, said set-point diode rectifying said first amplifier's alternating voltage output signal, and transmitting said first amplifier's output signal to said second operational amplifier, wherein said second amplifier is characterized in that it is operative to compare said rectified signal with a certain preselected threshold signal, and to transmit a trigger signal every time said rectified signal exceeds said threshold signal; a counter, operatively connected to said second amplifier for receiving each trigger signal from the same, said counter being characterized in that it counts the number of transmissions of said trigger signal from said second amplifier during a given time period, and outputs a malfunction cut-off signal in the event such number exceeds a certain preselected number during such period; and a switch, connectable to at least one of said power supply wires, and connected to said counter in a manner such that said switch is operable to disconnect said lamp from said power source in response to the output of said malfunction cut-off signal from said counter.