Open neutral detector

Patent metadata

Field	Value
Publication number	US-11322929-B2
Application number	US-202017121296-A
Country	US
Kind code	B2
Filing date	Dec 14, 2020
Priority date	Dec 9, 2016
Publication date	May 3, 2022
Grant date	May 3, 2022

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. An apparatus for detecting an open neutral condition in a split phase power system for delivering power to an electrical distribution system, the apparatus comprising:
a first powered line configured to output electricity to the electrical distribution system;
a second powered line configured to output electricity to the electrical distribution system;
a shared neutral line configured to provide a grounded neutral to the first and second powered lines;
a plurality of power monitors comprising a first power monitor configured for monitoring a first current on the first powered line, a second power monitor configured for monitoring a second current on the second powered line, and a third power monitor configured for monitoring a third current on the shared neutral line;
an indicator configured for indicating whether an open neutral condition exists in the split phase power system; and
a controller in communication with the plurality of power monitors, the controller configured for:
detecting when an open neutral condition is present in the split phase power 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
in response to detecting that the open neutral condition is present, causing the indicator to provide a visual indication that the open neutral condition is present.

2. The apparatus of claim 1 , 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 within the split phase power system.

3. The apparatus of claim 1 , 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 within the split phase power system.

4. The apparatus of claim 1 , further comprising an interrupter configured to selectively interrupt power supplied by the first and second powered lines, and wherein the controller is configured to cause the interrupter to interrupt the power supplied by the first and second powered lines in response to detecting that the open neutral condition is present within the split phase power system.

5. The apparatus of claim 1 , wherein the controller comprises analog hardware configured for detecting when the open neutral condition is present in the split phase power system.

6. The apparatus 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 split phase power system.

7. The apparatus of claim 1 , further comprising a protector housing configured to house at least a portion of the indicator and the controller.

8. The apparatus of claim 1 , wherein the indicator is disposed within a remote device.

9. The apparatus 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.

10. The apparatus 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 predefined threshold current value.

11. The apparatus of claim 10 , wherein the predefined threshold current value is less than 0.5 Amps.

12. The apparatus of claim 1 , further comprising a power source plug configured for being mated to a 50 A power pedestal.

13. The apparatus of claim 1 , further comprising an output power plug configured to accept a 50 A-rated plug from a recreational vehicle (RV) power distribution system.

14. The apparatus of claim 1 , wherein the first powered line, the second powered line, and the neutral line are connected to a recreational vehicle (RV) service configured to supply at least approximately fifty amps of electrical current and wherein the first powered line, the second powered line, and the neutral line are connected to an RV electrical distribution system.

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

• 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

• H02H3/20

  responsive to excess voltage · CPC title