AIRPORT LIGHTING MONITORING SYSTEM AND SYSTEM COMPONENTS

• US 3,715,741 A
• Filed: 02/09/1971
• Issued: 02/06/1973
• Est. Priority Date: 02/09/1971
• Status: Expired due to Term

• Current Assignee: Eagle Signal Controls Corp.
• Original Assignee: Ernest M. Purcell, Jan Keizer, John E. Mcwade, Wilcy I. Moore
• Inventors: McWade, John E., Keizer, Jan, Purcell, Ernest M., Moore, Wilcy I.
• Primary Examiner(s): Caldwell, John W.
• Assistant Examiner(s): Partridge, Scott F.
• Application Number:
  US05/113,821
• Time in Patent Office: 728 Days
• Field of Search: 340/248A,251,248,253,25,26,213,409,412,413,223 315/120 307/235 328/147 323/6,2
• US Class Current: 340/953
• CPC Class Codes: B64F 1/20 Arrangement of optical beacons
• CPC Class Codes: G08G 1/097 Supervising of traffic control systems, e.g. by giving an alarm if two crossing streets have green light simultaneously
• CPC Class Codes: H05B 47/235 with communication between the lamps and a central unit

Abstract

A monitoring system is provided for airport lighting installations employing series connected incandescent lamps. For each lamp there is a fault detector unit with voltage and overcurrent relays supplying an output whenever lamp current or voltage is deficient. There is also a fault detector for supplying an output when output current of a current regulator deviates from the value for which the lamp-current regulator is set. The lamps are divided into groups and for each group there is a field data acquisition unit. The field data acquisition units in turn, are connected in groups to a master controller with an output to suitable fault-indicating displays to warn of unsafe conditions. The master controller includes a clock circuit, logic for converting data from the field data acquisition units to form for actuating printers and for actuating accumulative fault display, and a sequencer for enabling data from successive groups of field data acquisition units to be handled by a single master controller. There is a print-out, identifying lamp circuits with faults and the runway in which they occur. For each runway there is an accumulative fault display indicating the number of faults in that runway.

Claims

1. A monitoring system for electrical circuits comprising in combination:

A circuit fault detector for each electrical circuit to be monitored, said fault detector comprising a relay with a series winding for producing an output signal whenever the circuit is open current therein is below a predetermined value, a field data acquisition unit having input lines from each such fault detector and a clock pulse input line, a master controller indicating means sequentially responsive to the master controller, the master controller having an input line from the field data acquisition unit, a clock delivering clock pulses to the field data acquisition unit, the field data acquisition unit including counter means responsive to the master controller clock pulses and data selector means with an input line from each circuit fault detector and counter means for advancing the data selector to cause signals to be supplied to the master controller from a fault detector of a circuit having a fault in the same sequence as indicating means responds to the master controller, the indicating means having means for identifying circuits to be monitored in the same sequence as the fault detector signals are supplied to the data selector, whereby the occurrence of a fault produces a signal identifying the circuit in which the fault has occurred.

2. A monitoring system as in claim 1 wherein the circuits to be monitored are divided into groups and the field data acquisition unit includes counter means with outputs for controlling the data selector, the data selector has control means for actuating the output in sequence according to the sequence of connection of the groups of fault detectors, the fault indicator responsive to the master controller has group identifying means, and the master controller is provided with means for causing the indicator to function in response to a fault detector in sequence according to a group for which the indicator is connected when a fault indication is produced by a fault detector.

3. A monitoring system for airport lighting lamp circuits, comprising in combination:

A circuit fault detector for each lamp circuit to be monitored, a field data acquisition unit having input lines from each such fault detector and a clock-pulse input line, a master controller and indicating means sequentially responsive to the maSter controller, the master controller having an input line from the field data acquisition unit, a clock delivering clock pulses to the field data acquisition unit, the field data acquisition unit including counter means responsive to the master controller clock pulses and data selector means with an input line from each circuit fault detector and counter means for advancing the data selector to cause signals to be supplied to the master controller from a fault detector of a lamp circuit having a fault in the same sequence as indicating means responsive to the master controller, the indicating means having means for identifying the lamp circuit to be monitored in the same sequence as the fault detector signals are supplied to the data selector, whereby the occurrence of a fault produces a signal identifying the lamp circuit in which the fault has occurred, the lamp circuits to be monitored being divided into groups and the field data acquisition unit including counter means with outputs for controlling the data selector, the data selector having control means for actuating the output in sequence according to the sequence of connection of the groups of fault detectors, the fault indicator responsive to the master controller having group identifying means, and the master controller being provided with means for causing the indicator to function in response to a fault detector in sequence according to the group for which the indicator is connected when a fault indication is produced by fault detector, each fault detector including a relay for producing an output signal when the lamp circuit is open or the current therein is below a predetermined value.

4. A monitoring system as described in claim 3 wherein the fault detector includes a voltage relay which produces an output signal from the fault detector when the lamp voltage falls below a predetermined value.

5. A monitoring system as described in claim 4 wherein the voltage relay has a winding connected across the lamp circuit in series with normally open contacts of the current relay so that the voltage relay cannot be energized when no current is flowing.

6. A monitoring system as described in claim 5 wherein the voltage relay is a direct current relay and the lamp circuit is an alternating current circuit, and a rectifier is connected in series with the winding of the voltage relay.

7. A monitoring system as described in claim 6 wherein a zener diode is connected in series with the rectifier designed for maintenance of a voltage comparable with but below that at which it is desired that the voltage relay shall become de-energized.

8. A monitoring system as described in claim 7 wherein a lamp current regulator is provided having a plurality of current regulation settings, for each of which a control circuit is provided, an adjustable voltage source responsive to such control circuits for producing different voltages depending upon the actuation of the control circuits for producing voltages corresponding to the current settings of the current regulator, a device is provided for producing a voltage corresponding to the actual current flow in the lamp circuit and means are provided for producing a fault signal whenever a predetermined deviation between the two voltages is exceeded.

9. A monitoring system as described in claim 8 wherein a plurality of isolation transformers are provided with primary and secondary windings, each having a secondary winding connected to one of the lamp circuits for energizing the same and a primary winding connected in series with the primary windings of the other isolation transformers in a substantially constant-current supply circuit.

10. A fault detector for the circuit of an electrically energized device comprising in combination:

A pair of current input terminals, a pair of output terminals adapted to be connected to an electrically energized device, a first conductor connected between one of the input terminals and one of the output terminals, a secoNd conductor connected between the other input terminal and the other output terminal, a current relay having contacts and a winding in series with the first conductor, a voltage relay having contacts serving as output signal contacts and winding connected across said device in series with said current relay contacts and means responsive to the position of the voltage relay contacts to produce a fault signal.

11. A fault detector for the circuit of an electrically energized device comprising in combination:

a pair of current input terminals, a pair of output terminals adapted to be connected to an electrically energized device, a first conductor connected between one of the input terminals and one of the output terminals, a second conductor connected between the other input terminal and the other output terminal, a current relay having contacts and a winding in series with the first conductor, and means responsive to the position of the contacts corresponding to failure of a predetermined value of current to flow through the relay winding to produce a fault signal, a second relay being provided having a winding and contacts to which the fault signal means are responsive, the winding of the second relay and the contacts of the first relay being connected in series between the first and second conductors at a point between the winding of the current relay and the output terminals.

12. A detector as described in claim 11 wherein the input terminals are adapted to be connected to a source of alternating current, the current relay is an alternating-current relay, the second relay is a direct-current relay and a rectifier is connected in series with the winding of the direct-current relay.

13. A fault detector as described in claim 12 wherein the second relay is a voltage relay and a zener diode is connected in series with the voltage relay winding and the said rectifier, and the zener diode is designed for a voltage approaching, but below that occuring at the supply terminals when the fault indication is desired.

14. A fault detector as described in claim 13 wherein a capacitor is connected across the winding of the voltage relay.

15. A detector as described in claim 14 wherein the input terminals are the secondary terminals of a current transformer and the output terminals are lamp terminals.

16. A current level fault detector comprising in combination:

a step-type current regulator of the type having a plurality of control circuits each for a different value and with a separate selector conductor arranged to produce a current of a different predetermined value with energization of different control circuits, a source of indicator voltage, a voltage divider connected thereto with a plurality of connected means, each responsive to one of the current regulator control circuits for supplying different indicator voltages according to which of the control circuits is energized for supplying different voltages to correspond with different levels of current intended to be produced by the current regulator, the current regulator having an output circuit, means connected in the output circuit for producing a voltage corresponding to the actual current flow in the output circuit of the current regulator, and means for comparing such voltage with the indicator voltage and means responsive to difference between such voltage and the indicator voltage.

17. A current-level fault detector as described in claim 16 wherein means are provided for producing a fault signal in response to deviation between the voltages of the indicator voltage source and the current responsive voltage exceeding a predetermined value.

18. A current-level fault detector as described in claim 17 wherein a current transformer is connected in series with the output circuit of the current regulator and has a secondary winding serving as means for producing a voltage representative of output current flow, and wherein a differential amplifier iS provided having opposing input connections and an output for producing a fault indication, one of the input connections being connected to the said source of indicator voltage and the other input connection being connected to receive the voltage of the secondary winding of the current transformer.

19. A current-level fault detector as described in claim 18 wherein the source of indicator voltage is a direct-current source and a rectifier is interposed between the secondary winding of the current transformer and the second input connection of the differential amplifier.

20. A current-level fault detector as described in claim 19 wherein the rectifier is a full-wave rectifier and a resistor is connected across the secondary winding of the current transformer to limit the voltage thereof to a predetermined value.

21. A monitoring system for electrical circuits comprising in combination:

a plurality of current-level sensors, each at a location of a device to be monitored, a field data acquisition unit having a clock pulse input line, a master controller and indicating means sequentially responsive to the master controller, the master controller having an input line from the field data acquisition unit, a clock delivering clock pulses to the field data acquisition unit, the field data acquisition unit including counter means responsive to the master controller clock pulses and data selector means with an input line from each sensor and counter means for advancing the data selector to cause signals to be supplied to the master controller from a sensor at a location having a condition to be monitored in the same sequence as indicating means responds to the master controller, the indicating means having means for identifying sensor locations to be monitored in the same sequence as the sensor signals are supplied to the data selector, whereby the occurrence of a condition to be monitored produces a signal identifying the location at which the sensor has responded, each sensor comprising a current relay having a winding and a pair of contacts and a voltage relay having contacts, the position of which serves as a sensor indication, and having a winding connected in series with the current relay contacts across the device to be monitored, the current-relay winding being connected in series with the device to be monitored.