Electrical system with circuit limiter

• US 8,350,406 B2
• Filed: 04/18/2012
• Issued: 01/08/2013
• Est. Priority Date: 04/18/2011
• Status: Active Grant

• Current Assignee: Norman R. Byrne
• Original Assignee: Norman R. Byrne
• Inventors: Byrne, Norman R., Warwick, Timothy J., Gibson, Shawn R.
• Primary Examiner(s): AMAYA, CARLOS DAVID
• Application Number:
  US13/449,701
• Publication Number:
  US 20120261988A1
• Time in Patent Office: 265 Days
• Field of Search: 307/35, 307/38, 307/39, 307/116
• US Class Current: 307/38
• CPC Class Codes: H01R 13/6616 with resistor
• CPC Class Codes: H01R 13/70 with built-in switch
• CPC Class Codes: H01R 25/003 the coupling part being secured only to wires or cables
• CPC Class Codes: H01R 25/168 the connecting locations being situated away from the rail or bus-bar
• CPC Class Codes: H02J 3/00 Circuit arrangements for ac mains or ac distribution networks

Abstract

An electrical power distribution system automatically limits the number of substantially similar or identical power cable assemblies that are electrically energizable from a power source. A control unit is connected between the power source and the power cable assemblies, and limits the number of power cable assemblies that can be energized in the system by sensing the voltage in a sensing circuit. An applied voltage in the sensing circuit changes in a predictable manner corresponding to the number of power cable assemblies that are electrically connected in the circuit. Each power cable assembly includes an impedance element that is added to the sensing circuit when the corresponding power cable assembly is coupled to the system, and once the detected voltage is beyond a predetermined threshold value, the control unit will ensure that the power cable assemblies are not energized by the power source.

Claims

1. An electrical power distribution system comprising:

at least one power outlet receptacle;

at least one power cable assembly comprising (i) a main power cable subassembly having at least two power conductors, at least two signal conductors, and first and second electrical connectors at opposite end portions of said main power cable subassembly, (ii) an electrical impedance element electrically coupled to at least one of said signal conductors, and (iii) an outlet feed cable configured to be electrically coupled to said power outlet receptacle and to said power conductors in said main power cable sub assembly;

a control unit in electrical communication with said power conductors and said signal conductors of said main power cable subassembly, said control unit comprising an electrical switch associated with at least one of said power conductors and operable to selectively prevent a flow of electricity through said power conductors, and a controller in electrical communication with said signal conductors and said electrical switch;

wherein said controller is operable to detect a number of main power cable subassemblies coupled together in said electrical power distribution system by measuring a voltage in said signal conductors, and wherein said control unit is operable to close said electrical switch so as to permit a flow of electricity through said at least two power conductors when the number of main power cable subassemblies in said electrical power distribution system is detected by said controller as being less than or equal to a predetermined number.

2. The electrical power distribution system of claim 1, wherein said main power cable subassembly comprises at least three power conductors including a line conductor, a neutral conductor, and a ground conductor.

3. The electrical power distribution system of claim 1, wherein said electrical impedance element comprises an electrical resistor.

4. The electrical power distribution system of claim 1, wherein said electrical impedance element is disposed in one of said first and second electrical connectors of said main power cable subassembly.

5. The electrical power distribution system of claim 1, wherein said controller comprises an electrical converter in electrical communication with said at least two power conductors and with said signal conductors, said electrical converter configured to convert a relatively higher voltage electrical power to a relatively lower voltage electrical power that is applied to said signal conductors.

6. The electrical power distribution system of claim 1, wherein said outlet feed cable comprises at least two power feed conductors that are electrically coupled to respective ones of said at least two power conductors of said main power cable subassembly at said first electrical connector, and wherein said outlet feed cable does not include any electrical conductors in communication with said signal conductors of said main power cable subassembly.

7. The electrical power distribution system of claim 6, wherein said power outlet receptacle is a pop-up power outlet receptacle that is configured to be supported in a recess at a work surface.

8. The electrical power distribution system of claim 1, wherein said first electrical connector is configured to mechanically and electrically couple said at least two power conductors and said signal conductors of a first of said main power cable subassemblies with said at least two power conductors and said signal conductors at said second electrical connector of a second of said main power cable subassemblies.

9. The electrical power distribution system of claim 1, wherein said control unit comprises first and second power outfeed cables, each power outfeed cable comprising a plurality of power outfeed conductors and at least two outfeed signal conductors that are simultaneously electrically connectable to respective ones of said power conductors and said signal conductors of a different one of said power cable assemblies.

10. An electrical power distribution system comprising:

at least one power cable assembly comprising a main power cable subassembly having a plurality of power conductors that are electrically connectable to an electrical power source, at least two signal conductors, and an electrical impedance element electrically coupled to at least one of said signal conductors, said main power cable subassembly having opposite end portions with each end portion having a respective electrical connector, and said power cable assembly further comprising an outlet feed cable;

a control unit in electrical communication with said power conductors and said signal conductors of said at least one power cable assembly, said control unit comprising an electrical switch associated with at least one of said power conductors and operable to selectively energize and de-energize at least one of said power conductors, and a controller in electrical communication with said signal conductors and said electrical switch; and

wherein said controller is operable to measure a voltage drop across said signal conductors, and wherein said controller is further operable to close said electrical switch so as to permit a flow of electricity through said power conductors when the number of main power cable subassemblies in said electrical power distribution system is detected by said controller as being less than or equal to a predetermined number.

11. The electrical power distribution system of claim 10, wherein said control unit comprises an electrical converter in electrical communication with said signal conductors and with said electrical power conductors that receive electrical power from the power source, said electrical converter configured to convert a relatively higher voltage electrical power to a relatively lower voltage electrical power applied to said signal conductors.

12. The electrical power distribution system of claim 10, wherein said outlet feed cable comprises at least two power feed conductors that are electrically coupled to respective ones of said power conductors of said main power cable subassembly at one of said electrical connectors.

13. The electrical power distribution system of claim 12, wherein said one of said electrical connectors is configured to mechanically and electrically couple said power conductors and said signal conductors with said power conductors and said signal conductors at a second electrical connector of another of said main power cable subassemblies.

14. The electrical power distribution system of claim 10, wherein said power outlet receptacle is a pop-up power outlet receptacle that is configured to be supported at a work surface.

15. The electrical power distribution system of claim 10, wherein at least one of said cable assembly and said control unit is configured to be positioned substantially below a work surface.

16. The electrical power distribution system of claim 10, further in combination with a work surface.

17. An electrical power distribution system comprising:

a plurality of power outlet modules, at least one of said power outlet modules having a power outlet receptacle;

a plurality of power cable assemblies interconnected in a chain with an upstream one of said power cable assemblies electrically connected with a control unit, each of said power cable assemblies comprising (i) a main power cable subassembly having at least two power conductors, at least two signal conductors, and first and second electrical connectors at opposite end portions of said main power cable subassembly, each of said connectors adapted to connect with one of said connectors of an adjacent one of said power cable assemblies, (ii) an electrical impedance element electrically coupled to at least one of said signal conductors in one of said first and second electrical connectors, and (iii) an outlet feed cable comprising at least two power feed conductors that are electrically coupled to respective ones of said at least two power conductors of said main power cable subassembly at said first electrical connector, wherein said outlet feed cable is configured to be electrically coupled to one of said power outlet modules and to said power conductors in said main power cable subassembly, and wherein said power outlet modules do not include any electrical conductors in communication with said signal conductors of said main power cable subassemblies;

said control unit in electrical communication with said power conductors and said signal conductors of said main power cable subassembly, said control unit comprising (i) an electrical switch associated with at least one of said power conductors and operable to selectively prevent a flow of electricity through said power conductors, and (ii) a controller in electrical communication with said signal conductors and said electrical switch, said controller comprising an electrical converter in electrical communication with said signal conductors to apply a low voltage signal to said signal conductors;

wherein said controller further includes a voltage sensor in electrical communication with said signal conductors, wherein said voltage sensor is operable to detect a number of main power cable subassemblies coupled together in said electrical power distribution system by measuring a voltage in said signal conductors, and wherein said control unit is operable to close said electrical switch so as to permit a flow of electricity through said at least two power conductors when the number of main power cable subassemblies in said electrical power distribution system is detected by said controller as being less than or equal to a predetermined number.

18. The electrical power distribution system of claim 17, wherein said control unit comprises first and second power outfeed cables, each power outfeed cable comprising a plurality of power outfeed conductors and at least two outfeed signal conductors that are simultaneously electrically connectable to respective ones of said power conductors and said signal conductors of a different one of said power cable assemblies.

19. The electrical power distribution system of claim 17, wherein said power outlet module comprises a pop-up power outlet receptacle that is configured to be supported in a recess at a work surface.

20. The electrical power distribution system of claim 19, wherein at least one of said cable assembly and said control unit is configured to be positioned substantially below a work surface.