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Title: Apparatus for detecting diode failures in multiple diode rectifier bridges
Claims: What is claimed is: 1. For apparatus of the type including an AC voltage source and rectifier means having an arrangement of rectifying devices for rectifying the AC voltage from the voltage source to provide a DC voltage, means for detecting failed rectifying devices in the rectifier means comprising: detector means having an arrangement of rectifying devices corresponding to the rectifier means arrangement of rectifying devices; the detector means connected to the AC voltage source for rectifying the AC voltage to provide a DC voltage; means arranged with the detector means rectifying devices for providing a phantom neutral voltage; and means connected to the rectifier means, the detector means and the means for providing a phantom neutral voltage, and responsive to the rectifier means DC voltage, the detector means DC voltage and the phantom neutral voltage for detecting predetermined relationships between the rectifier means DC voltage and the detector means DC voltage, and between the phantom neutral voltage and the rectifier means DC voltage, and for providing outputs indicative of said relationships. 2. Means as described by claim 1, wherein the means connected to the rectifier means, the detector means and the means for providing a phantom neutral voltage, and responsive to the rectifier means DC voltage, the detector means DC voltage and the phantom neutral voltage for detecting predetermined relationships between the rectifier means DC voltage and the detector means DC voltage, and between the phantom neutral voltage and the rectifier means DC voltage, and for providing outputs indicative of said relationships includes: first means for detecting when the rectifier means DC voltage and the detector means DC voltage are other than equal, and for thereupon providing an output which is indicative of an open rectifier device in the rectifier means; and second means for detecting when the phantom neutral voltage and the rectifier means DC voltage are at other than a predetermined ratio, and for thereupon providing an output which is indicative of a shorted rectifier device in the rectifier means. 3. Means as described by claim 2, including: an OR gate connected to the first and second means and responsive to one of the outputs therefrom for providing an output indicative of a failed rectifying device in the rectifier means. 4. Means as described by claim 3 including: means for utilizing the output indicative of a failed rectifier device in the rectifier means. 5. Means as described by claim 2, wherein the first means includes: comparator means connected to the rectifier means and to the detector means and comparing the ripple voltages of both of said means, with an open rectifying device causing a peak to be missing in the rectifier means ripple voltage whereupon the comparator means provides the output indicative of an open rectifying device in the rectifier means. 6. Means as described by claim 2, wherein the second means includes: means connected to the rectifier means and responsive to the DC voltage therefrom for providing a reference voltage; and comparator means connected to the reference voltage means and to the phantom voltage means for comparing the voltages therefrom, with a shorted rectifying device causing a shift in the phantom voltage relative to the reference voltage whereupon the comparator means provides the output indicative of a shorted rectifying device in the rectifier means. 7. Means as described by claim 1, wherein the means arranged with the detector means rectifying devices for providing a phantom neutral voltage includes: a plurality of resistors, each of which is connected to a corresponding rectifier device; the resistors connected to a common connection; and the common connection providing the phantom neutral voltage. 8. Means as described by claim 5, wherein: the arrangement of rectifying devices in the rectifier means and in the detector means includes rectifying devices which provide DC voltages in positive and negative senses; the comparator means includes first and second comparators, each having inverting and non-inverting input terminals; the rectifying devices in the rectifier means for providing a DC voltage in a positive sense connected to the non-inverting input terminal of the first comparator and the rectifying devices in the detector means for providing a DC voltage in a positive sense connected to the inverting input terminal of said first comparator, with a missing peak causing the voltage at the non-inverting input terminal of the first comparator to decrease below the voltage at the inverting input terminal, whereupon the first comparator provides an output indicative of an open rectifier device in the rectifying means which provides a DC voltage in the positive sense; and the rectifying devices in the rectifier means for providing a DC voltage in a negative sense connected to the inverting input terminal of the second comparator and the rectifying devices in the detector means for providing a DC voltage in a negative sense connected to the non-inverting input terminal of said second comparator, with a missing peak causing the voltage at the inverting input terminal of the second comparator to increase above the voltage at the non-inverting input terminal, whereupon the second comparator provides an output indicative of an open rectifier device in the rectifying means which provides a DC voltage in the negative sense. 9. Means as described by claim 6, wherein: the arrangement of rectifying devices in the rectifying means and in the detector means includes rectifying devices which provide DC voltages in positive and negative senses; the comparator means includes first and second comparators each having inverting and non-inverting input terminals; the means for providing a reference voltage connected to the non-inverting input terminal of the first comparator and to the inverting input terminal of the second comparator; the means for providing a phantom voltage connected to the inverting input terminal of the first comparator and to the non-inverting input terminal of the second comparator; a shorted rectifying device in the rectifier means which provides a DC voltage in a positive sense causing the phantom neutral voltage to be displaced in the positive sense which causes the voltage at the inverting input terminal of the first comparator to go in a positive sense with respect to the voltage at the non-inverting input terminal, whereupon the first comparator provides an output indicative of a shorted rectifying device in the rectifier means which provides a DC voltage in the positive sense; and a shorted rectifying device in the rectifier means which provides a DC voltage in a negative sense causing the phantom neutral voltage to be displaced in the negative sense which causes the voltage at the non-inverting input terminal of the second comparator to go in a negative sense with respect to the voltage at the inverting input terminal, whereupon the second comparator provides an output indicative of a shorted rectifying device in the rectifying means which provides a DC voltage in the negative sense. Other info: Inventors: Wang, Shou-I (Old Bridge, NJ, US) Hansen, Jr., Charles M. (Ocean City, NJ, US) Application Number: 936266 Filing Date: 1978-08-22 Publication_date: 1980-01-29 Assignee: The Bendix Corporation (Teterboro, NJ) Primary Class(es): 340/645 340/650, 363/53 Other Classes: US Patent Ref:
Other Refs: Primary Examiner: Brigance, Gerald Assistant Examiner: Attorney: Cuoco; Anthony F., Thornton; William F. |
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