Fault detection circuit for use in determining the existence of a fault in any one of a plurality of DC loads
AssigneeCox & Company, Inc.
InventorMartin Schuyler
Life of this patent
Estimating the term…
Abstract
A fault detection circuit for a plurality of DC loads uses a reference load as a benchmark. The voltages at the centerpoints of the loads to be monitored are monitored and compared with the voltage of the centerpoint of the reference load. The comparison is affected by faults which do not affect all loads equally (as by a short or open) and is unaffected by faults which do affect all loads equally (as by changes in voltage of the source).
Claims13
A fault detection circuit for determining the existence of a fault in any one of a plurality of center-tapped loads which are supplied by a DC source, comprising:
- a center-tapped reference load having two equal resistances connected to a floating reference centerpoint, each resistance being connected to a corresponding side of the source;
- means for monitoring the voltages at the centerpoints of all the center-tapped loads to be monitored;
- and
- means for comparing said monitored voltages with the voltage of said reference centerpoint.
A fault detection circuit for determining the existence of a fault in any one of a plurality of center-tapped loads which are supplied by a DC source, comprising:
- a center-tapped reference load having two equal resistances connected to a floating reference centerpoint, each resistance being connected to a corresponding side of the source;
- means for monitoring the voltages at the centerpoints of all the center-tapped loads to be monitored, said means comprising
- a) a first set of n diodes, n being an integer equal to the number of loads of be monitored, all diodes in the first set having their cathodes connected together and each diode in the first set having its anode connected to the centerpoint of a corresponding single one of the loads to be monitored,
- b) a second set of n diodes, all diodes in the second set having their anodes connected together and each diode in the second set having its cathode connected to the centerpoint of a corresponding single one of the loads to be monitored;
- and
- means for comparing said monitored voltages with the voltage of said reference centerpoint.
A fault detection circuit for determining the existence of a fault in any one of a plurality of center-tapped loads which are supplied by a DC source, comprising:
- a reference load network having two equal resistances connected in series with each other through a small bias resistor, each of the two equal resistances being connected to a corresponding side of the source;
- means for monitoring the voltages at the centerpoints of all the center-tapped loads to be monitored, said means comprising
- a) a first set of n diodes, n being an integer equal to the number of loads of be monitored, all diodes in the first set having their cathodes connected together and each diode in the first set having its anode connected to the centerpoint of a corresponding single one of the loads to be monitored,
- b) a second set of n diodes, all diodes in the second set having their anodes connected together and each diode in the second set having its cathode connected to the centerpoint of a corresponding single one of the loads to be monitored;
- and
- means for comparing said monitored voltages with the voltages at the ends of the small bias resistor.
A fault detection circuit for determining the existence of a fault in any one of a plurality of center-tapped loads which are supplied by a DC source, comprising:
- a reference load network having two equal resistances connected in series with each other through a small bias resistor, each of said two equal resistances being connected to a corresponding side of the source;
- means for monitoring the voltages at the centerpoints of all the center-tapped loads to be monitored;
- and
- means for comparing said monitored voltages with the voltages at the ends of said small bias resistor.
A fault detection system for use with a DC source, comprising:
- a plurality of center-tapped loads;
- a center-tapped reference load having two equal resistances connected to a floating reference centerpoint, each resistance being connected to a corresponding side of the source;
- means for monitoring the voltages at the centerpoints of all the center-tapped loads to be monitored;
- and
- means for comparing said monitored voltages with the voltage of said reference centerpoint.
A fault detection system for use with a DC source, comprising:
- a plurality of center-tapped loads;
- a reference load network having two equal resistances connected in series with each other through a small bias resistor, each of said two equal resistances being connected to a corresponding side of the source;
- means for monitoring the voltages at the centerpoints of all the center-tapped loads to be monitored;
- and
- means for comparing said monitored voltages with the voltages at the ends of the small bias resistor.
Dependencies are inferred from the claim text.