Open neutral detector

Patent metadata

Field	Value
Publication number	US-11769999-B2
Application number	US-202218060757-A
Country	US
Kind code	B2
Filing date	Dec 1, 2022
Priority date	Dec 9, 2016
Publication date	Sep 26, 2023
Grant date	Sep 26, 2023

Abstract

An apparatus for detecting an open neutral condition in a split phase power system is described. The apparatus includes two powered lines providing output electricity to an electrical distribution system and a shared neutral line providing a grounded neutral to the first and second powered lines. The apparatus is configured for detecting when an open neutral condition is present in the split phase power system by determining when a power current is present on one or both of the first and second powered lines while a return current is not present on the neutral line; and in response to detecting that the open neutral condition is present, causing an interrupter to interrupt the power supplied by the first and second powered lines or to generate a signal indicating an open condition.

First claim

The invention claimed is:

1. A device for detecting an open neutral condition in a split phase power system for delivering power to an electrical distribution system, the device configured for being electrically coupled upstream of the device to a power source and downstream of the device to the electrical distribution system, and comprising:
a plurality of power monitors comprising a first power monitor configured for monitoring a first current on a first powered line connected to the electrical distribution system, a second power monitor configured for monitoring a second current on a second powered line connected to the electrical distribution system and a third power monitor configured for monitoring a third current on a neutral line connected to the electrical distribution system;
a controller in communication with the plurality of power monitors, the controller configured for:
detecting when an open neutral condition is present in the electrical distribution system by determining, based at least in part on one or more of the first current, the second current, and the third current, instances when a power current is present on one or both of the first and second powered lines while a return current is not present on the neutral line, and

causing an indication that the open neutral condition is present in the electrical distribution system in response to detecting the open neutral condition.

2. The device of claim 1 , wherein the electrical distribution system downstream of the device is connected to the load of an RV.

3. The device of claim 1 , wherein a detected open neutral condition in the electrical distribution system is an open neutral condition in the RV wiring.

4. The device of claim 1 , wherein the controller is further configured for detecting an open neutral condition upstream of the device at a campground power outlet.

5. The device of claim 1 , further comprising an indicator, wherein the controller is configured to cause the indication that the open neutral condition is present in the electrical distribution system using the indicator.

6. The device of claim 5 , wherein the indicator comprises an indication light, and wherein the controller is configured to cause the indication light to be illuminated in response to detecting that the open neutral condition is present.

7. The device of claim 5 , wherein the indicator comprises a display screen, and wherein the controller is configured to cause the display screen to visually indicate that the open neutral condition is present in response to detecting that the open neutral condition is present.

8. The device of claim 5 , further comprising an interrupter in communication with the controller.

9. The device of claim 8 , wherein in response to detecting that the open neutral condition is present in the electrical distribution system, the controller is configured to cause the interrupter to interrupt power supplied by the first and second powered lines.

10. The device of claim 9 , wherein the device powers the indicator in response to detecting the open neutral condition is present in the electrical distribution system.

11. The device of claim 8 , wherein in response to detecting that the open neutral condition is present, the controller is configured to cause the interrupter to interrupt the power source providing power to the first and second powered lines.

12. The device of claim 1 , wherein the controller comprises a processor, and wherein the processor is configured to execute stored instructions to determine when the open neutral condition is present in the electrical distribution system.

13. The device of claim 12 , wherein the controller is configured to utilize one or more of stored software or firmware to execute stored instructions to detect when the open neutral condition is present.

14. The device of claim 1 , wherein the device comprises analog hardware configured for detecting when the open neutral condition is present.

15. The device of claim 1 , wherein the controller is configured to determine that the return current is not present on the neutral line by detecting instances when the third current is approximately zero.

16. The device of claim 1 , wherein the controller is configured to determine that the return current is not present on the neutral line by detecting instances when the third current is below a threshold current value.

17. The device of claim 16 , wherein the threshold current value is 0.5 Amps.

18. The device of claim 16 , wherein the threshold current value is between 0.5 and 0.7 Amps.

19. The device of claim 1 , wherein the first powered line, the second powered line, and the neutral line are connected to an RV campground outlet configured to supply at least approximately fifty amps of electrical current.

20. The device of claim 1 , wherein detecting that the open neutral condition is present comprises, upon determining that the power current is present on at least one of the first and second powered lines, allowing a period of time to elapse before determining whether the return current is present on the neutral line.

Assignees

• Southwire Co Llc

Inventors

• Oldham Jr Donald Paul
• Moussa Hamze

Classifications

• H02H3/338 Primary

  also responsive to wiring error, e.g. loss of neutral, break · CPC title

• H02H3/20

  responsive to excess voltage · CPC title

• H02H5/10

  responsive to mechanical injury, e.g. rupture of line, breakage of earth connection · CPC title

• H02H5/105

  responsive to deterioration or interruption of earth connection (for preventing switching-on H02H11/001) · CPC title