Signal loss detector for three phase circuit

Claim 2

A phase loss detector for a three phase circuit comprising: first, second, and third sensing means coupled to each phase and operative to produce a facsimile signal of each signal phase; said first, second, and third sensing means connected in series so the facsimile signals are continuously summed; signal elimination means for blocking odd harmonic signals having a frequency higher than a fundamental frequency of said facsimile signal and coupled in series with said first, second, and third sensing means; and threshold responsive means coupled to an output of said signal elimination means.

Claim 3

A phase loss detector as defined in claim 1 wherein said first, second, and third sensing means are operative to produce signals signal uniformly proportional in magnitude to signals in each phase of the three phase circuit.

Claim 4

Circuitry for detecting a signal loss in any phase of a three-phase circuit comprising: first, second and third sensing means for producing first, second and third facsimile AC signals representative of a signal condition in each phase; means for summing said first, second and third facsimile AC signals; filter means coupled to said means for summing and operative to pass signals of a fundamental frequency of said facsimile AC signal and block odd harmonic signals having a higher frequency than the said fundamental frequency; and signal magnitude responsive means coupled to an output of said filter means, whereby a signal magnitude applied thereto indicates a signal loss in any phase of said three-phase circuit.

Claim 5

Circuitry for detecting a signal loss in any phase of a three-phase circuit comprising: first, second and third sensing means for producing first, second and third facsimile AC signals representative of a signal condition in each phase; means for summing said first, second and third facsimile AC signals; filter means coupled to said means for summing and operative to pass signals of a fundamental frequency of said facsimile AC signal and block odd harmonic signals having a higher frequency than the said fundamental frequency; and signal magnitude responsive means coupled to an output of said filter means, whereby a signal magnitude applied thereto indicates a signal loss in any phase of said three-phase circuit.

Claim 6

Circuitry as defined in claim 3 wherein said first, second, and third sensing means comprise first, second, and third transformer sensing windings coupled to transformers in a three phase system, and said means for summing comprises a series connection of said first, second, and third transformer sensing windings.

Claim 7

A three phase rectifier including input means to accept a three phase source, a three phase transformer arrangement coupled to be energized through said input means, a first, second, and third sense winding coupled to each phase of the three phase transformer arrangement, respectively, said first, second, and third sense windings connected in series to sum signals sensed thereby, a filter coupled to an output of the first, second, and third sense windings connected in series and operative to block off harmonic signals having a higher frequency than a fundamental signal frequency of a signal occurring in each phase monitored, and a signal threshold detector coupled to an output of said filter and operative to detect a signal magnitude indicative of a phase loss.

Claim 8

A three phase rectifier including input means to accept a three phase source, a three phase transformer arrangement coupled to be energized through said input means, a first, second, and third sense winding coupled to each phase of the three phase transformer arrangement, respectively, said first, second, and third sense windings connected in series to sum signals sensed thereby, a filter coupled to an output of the first, second, and third sense windings connected in series and operative to block off harmonic signals having a higher frequency than a fundamental signal frequency of a signal occurring in each phase monitored, and a signal threshold detector coupled to an output of said filter and operative to detect a signal magnitude indicative of a phase loss.

Claim 9

A three phase rectifier as defined in claim 5 wherein said first, second, and third sense windings have a uniform transformation ratio with respect to an input of said three phase transformer arrangement.