Phase failure detection system

Claim 2

A phase failure detection system for detecting phase failure in a polyphase power supply system, comprising: a polyphase source of alternating current connected with a plurality of power supply conductors; a plurality of sensing circuits, each of said sensing circuits including a switching means capable of providing a pulsating output signal comprised of a series of substantially rectangular pulses in response to a sinusoidal input signal; means connecting each of said sensing circuits across a different pair of said supply conductors whereby, the line-to-line voltages available on said supply conductors are simultaneously monitored by said sensing circuits and said sensing circuits are sequentially switched in accordance with the periodic waveforms of the line-to-line voltages, the substantially rectaNgular output signals of said sensing circuits having a first predetermined phase relationship when said system provides normal polyphase operation and a different predetermined phase relationship when a phase failure occurs; detection means connected with the outputs of said sensing circuits for simultaneously monitoring the outputs of all of said sensing circuits, said detection means including a switching means responsive to the phase relationship of said sensing circuit output signals and providing an output signal when said sensing circuit output signals have said different predetermined phase relationship; and indicating means connected with the output of said detection means for providing an indication in response to a phase failure.

Claim 3

A phase failure detection system for detecting phase failure in a three phase power supply, comprising: a three phase source of electric power having three output terminals; three supply conductors connected respectively with said output terminals; a transformer having three primary windings and three secondary windings; means connecting said primary windings in a delta-connection with said supply conductors; three gate means, each of said gate means capable of providing a pulsating output signal having pulses of predetermined duration in response to a sinusoidal input signal; means connecting each of said gate means with a different one of said secondary windings whereby, the line-to-line voltages available on said supply conductors sequentially enable each of said gate means in accordance with the periodic waveform of the respective line-to-line voltage coupled to the input of the gate means, the pulsating output signals of said gate means having a first predetermined phase relationship when said system provides normal three phase operation and a different predetermined phase relationship when a phase failure occurs; detection means connected with the outputs of said gate means for simultaneously monitoring the outputs of all three of said gate means, said detection means including a switching means responsive to the phase relationship of said gate means output signals and providing an output signal when said gate means output signals have said different predetermined phase relationship; and indicating means connected with the output of said detection means for providing an indication in response to a phase failure.

Claim 4

A phase failure detection system for detecting phase failure in a three phase power supply, comprising: a three phase source of electric power having three output terminals; three supply conductors connected respectively with said output terminals; a transformer having three primary windings and three secondary windings; means connecting said primary windings in a delta-connection with said supply conductors; three gate means, each of said gate means capable of providing a pulsating output signal having pulses of predetermined duration in response to a sinusoidal input signal; means connecting each of said gate means with a different one of said secondary windings whereby, the line-to-line voltages available on said supply conductors sequentially enable each of said gate means in accordance with the periodic waveform of the respective line-to-line voltage coupled to the input of the gate means, the pulsating output signals of said gate means having a first predetermined phase relationship when said system provides normal three phase operation and a different predetermined phase relationship when a phase failure occurs; detection means connected with the outputs of said gate means for simultaneously monitoring the outputs of all three of said gate means, said detection means including a switching means responsive to the phase relationship of said gate means output signals and providing an output signal when said gate means output signals have said different predetermined phase relationship; and indicating means connected with the output of said detection means for providing an indication in response to a phase failure.

Claim 5

A phase failure detection system for detecting phase failure in a three phase power supply, comprising: a three phase source of electric power having three output terminals; three supply conductors connected respectively with said output terminals; a transformer having three primary windings and three secondary windings; means connecting said primary windings in a delta connection with said supply conductors; three gate means, each of said gate means capable of providing a pulsating output signal comprised of a series of rectangular pulses of predetermined pulse width in response to a sinusoidal input signal; means connecting each of said gate means with a different one of said secondary windings whereby, the line-to-line voltages available on said supply conductors sequentially switch each of said gate means and said gate means provide said time displaced rectangular output pulses in accordance with the periodic waveforms of the respective line-to-line voltages coupled to the inputs of the gate means, the pulsating output signals of said gate means having a first predetermined phase relationship when said system provides normal three phase operation and a different predetermined phase relationship when a phase failure occurs; detection means connected with the outputs of said gate means for simultaneously monitoring the outputs of all three of said gate means, said detection means including a switching means responsive to the phase relationship of said gate means output signals and providing an output signal if said gate means output signals have said different predetermined phase relationship; and indicating meAns connected with the output of said detection means for providing an indication in response to a phase failure.

Claim 6

A phase failure detection system for detecting phase failure in a three phase power supply, comprising: a three phase source of electric power having three output terminals; three supply conductors connected respectively with said output terminals; a transformer having three primary windings and three secondary windings; means connecting said primary windings in a delta connection with said supply conductors; three gate means, each of said gate means capable of providing a pulsating output signal comprised of a series of rectangular pulses of predetermined pulse width in response to a sinusoidal input signal; means connecting each of said gate means with a different one of said secondary windings whereby, the line-to-line voltages available on said supply conductors sequentially switch each of said gate means and said gate means provide said time displaced rectangular output pulses in accordance with the periodic waveforms of the respective line-to-line voltages coupled to the inputs of the gate means, the pulsating output signals of said gate means having a first predetermined phase relationship when said system provides normal three phase operation and a different predetermined phase relationship when a phase failure occurs; detection means connected with the outputs of said gate means for simultaneously monitoring the outputs of all three of said gate means, said detection means including a switching means responsive to the phase relationship of said gate means output signals and providing an output signal if said gate means output signals have said different predetermined phase relationship; and indicating meAns connected with the output of said detection means for providing an indication in response to a phase failure.

Claim 7

A phase failure detection system for monitoring a three phase power supply and for providing an indication if the source fails to maintain three phase operation, comprising: a three phase source of electric power having three output terminals; three supply conductors connected respectively with said output terminals; a transformer having three primary windings and three secondary windings; means connecting said primary windings in a delta connection with said supply conductors; three gate means, each of said gate means capable of providing a pulsating output signal comprised of a series of rectangular pulses of predetermined pulse width in response to a sinusoidal input signal; means connecting each of said gate means with a different one of said secondary windings whereby, the line-to-line voltages available on said supply conductors sequentially switch each of said gate means and said gate means provide said time displaced rectangular output pulses in accordance with the periodic waveforms of the respective line-to-line voltages coupled to the inputs of the gate means, the pulsating output signals of said gate means having a first predetermined phase relationship when said system provides normal three phase operation and a different predetermined phase relationship when a phase failure occurs; each of said gate means providing a constant continuous output of like polarity in the absence of input signals from said secondary windings; detection means connected with the outputs of said gate means for simultaneously monitoring the outputs of all three of said gate means, said detection means including a switching means responsive to the output signals provided by said gate means and providing an output signal if said gate means output signals have either said different predetermined phase relationship to indicate single phase operation or said constant continuous output to indicate total loss of power; and indicating means connected with the output of said detection means for providing an indication in response to single phase operation or a total loss of power.

Claim 8

A phase failure detection system for monitoring a three phase power supply and for providing an indication if the source fails to maintain three phase operation, comprising: a three phase source of electric power having three output terminals; three supply conductors connected respectively with said output terminals; a transformer having three primary windings and three secondary windings; means connecting said primary windings in a delta connection with said supply conductors; three gate means, each of said gate means capable of providing a pulsating output signal comprised of a series of rectangular pulses of predetermined pulse width in response to a sinusoidal input signal; means connecting each of said gate means with a different one of said secondary windings whereby, the line-to-line voltages available on said supply conductors sequentially switch each of said gate means and said gate means provide said time displaced rectangular output pulses in accordance with the periodic waveforms of the respective line-to-line voltages coupled to the inputs of the gate means, the pulsating output signals of said gate means having a first predetermined phase relationship when said system provides normal three phase operation and a different predetermined phase relationship when a phase failure occurs; each of said gate means providing a constant continuous output of like polarity in the absence of input signals from said secondary windings; detection means connected with the outputs of said gate means for simultaneously monitoring the outputs of all three of said gate means, said detection means including a switching means responsive to the output signals provided by said gate means and providing an output signal if said gate means output signals have either said different predetermined phase relationship to indicate single phase operation or said constant continuous output to indicate total loss of power; and indicating means connected with the output of said detection means for providing an indication in response to single phase operation or a total loss of power.