ARC FAULT CIRCUIT INTERRUPTER, SYSTEMS, APPARATUS AND METHODS OF DETECTING AND INTERRUPTING ELECTRICAL FAULTS

• US 20100097733A1
• Filed: 12/18/2009
• Published: 04/22/2010
• Est. Priority Date: 12/14/2007
• Status: Active Grant

• Current Assignee: True-Safe Technologies, Inc. (Universal Health Services Incorporated)
• Original Assignee: True-Safe Technologies, Inc. (Universal Health Services Incorporated)
• Inventors: E., Tomimbang Wendell
• Granted Patent: US 8,879,218 B2
• Time in Patent Office: Days
• US Class Current: 361/42
• CPC Class Codes: G01R 31/50 Testing of electric apparatus, lines, cables or components for short-circuits, continuity, leakage current or incorrect line connections testing of sparking plugs H01T13/58
• CPC Class Codes: H02H 1/0015 Using arc detectors

Abstract

In all electrical circuits, various arcing conditions can arise, however, the primary ones are series arcing (low current arcing), and, parallel arcing (high current arcing). An arc fault circuit interrupter (“AFCI”) that protects for both series and parallel arcing is called a combination type. An AFCI is a device that controls the effects of electrical arcing by opening a circuit through a tripping mechanism that isolates the load from the supply line upon detection of an arcing condition. In this invention, this arc fault is detected by a circuit employing a Hall-Effect sensor (“HES”) integrated circuit, and a microprocessor among other components.

Claims

1. An apparatus for detecting series and parallel arc faults, overcurrent, overload, short circuit, ground and surge, in single or multi-phase electrical circuits, AC or DC, and then safely interrupting said circuit, said apparatus comprising:

a housing, circuitry, line and load side terminals, Hall Effect Current Sensor, power supply or automatic power switcher circuit, anti alias filter, programmable gain amplifier, buffer amplifier, microprocessor, reset button, trip button, test button, electromagnetic contactor, contactor position sensing circuit, miswire circuitry, visual indicators, audible alarms, and the associated mechanical, electrical, electro-mechanical and electronic components and interconnections.

2. The apparatus of claim 1, wherein said Hall Effect Current Sensor is an integrated circuit Hall Effect Current Sensor, has a Hall current drive, dynamic offset cancellation, gain and temperature coefficient adjustment, amplifiers, zero “

0”

current adjustment, analog and digital outputs, analog to digital converter.

3. The apparatus of claim 1, wherein said apparatus may be in different types or forms, including receptacles, receptacle outlets, circuit breakers, portable, cord, modular or integrated as part of another electrical system, equipment or device.

4. The apparatus of claim 1, wherein said apparatus further comprises an electrical circuitry with associated code parameters that limits or eliminates the occurrence of nuisance tripping by distinguishing arcs from normal electrical load signatures that mimics that of an arc.

5. The apparatus of claim 1, wherein said apparatus further comprises a housing, circuitry, line and load side terminals, Hall Effect Current Sensor;

power supply or automatic power switcher circuit, anti alias filter, programmable gain amplifier, buffer amplifier, microprocessor, test and reset buttons, electromagnetic contactor, contactor position sensing circuit, visual indicators, audible alarms, and the associated mechanical, electrical, electro-mechanical and electronic components and interconnections.

6. The apparatus of claim 1, wherein the Hall Effect Current Sensor therein further comprises a Hall current drive, dynamic offset cancellation, gain and temperature coefficient adjustment, amplifiers, zero “

0”

current adjustment, analog and digital outputs, an analog to digital converter, being power-driven and bi-directional, its output voltages being proportional to the current flow, having stable output offset voltage, having nearly zero magnetic hysteresis, and having ratiometric output from supply voltage, having additional circuit for detection of zero crossing, overcurrent or overload and other additional features that could be used for signaling and detection of arcs with other electrical faults.

7. The apparatus of claim 1, wherein the automatic power switcher therein further comprises an input rectifier and filter, inverter/chopper and controller, high frequency transformer, output rectifier and filter, along with the necessary components and interconnections, and said automatic power switcher circuit being a Switch Mode Power Supply circuit, said switcher employing a high frequency transformer and power switcher Integrated Circuit which automatically adopts to the input voltage from a given range of 80-265 VAC to provide constant DC voltage output or multiple outputs to the power driven components of said apparatus, said switcher minimizing internal heating in enclosed circuits with the use of high frequency transformers and microelectronic circuitry avoiding unnecessary conditioning systems and components, said switcher circuit providing stable DC output voltage regardless of fluctuations in the input voltage within the input voltage range of the device 80-265 VAC, said switcher circuit operating independently of the type of power source and is applicable for all configurations within the operating voltage range, i.e., Line-to-Line, Line-Neutral, with the same constant output DC voltage, said switcher circuit with the associated hardware and software program being an integral part of said apparatus.

8. The apparatus of claim 1, wherein the programmable gain amplifier therein, being used to maintain the signal amplitude of the output signal of the Hall Effect Current Sensor within a range suitable for Analog to Digital Conversion, as used in the detection of arc and other electrical faults, said programmable gain amplifer connecting the low input to the low output and both to the DC offset voltage allowing the AC component of the output signal from the Hall Effect Current Sensor to be amplified with variable gain while the DC component receives a constant gain, said programmable gain amplifier being Analog Devices, Inc.'"'"'s AD8231, said programmable gain amplifier being a low-drift digitally programmable instrumentation amplifier with programmable gains.

9. The apparatus of claim 1, wherein said apparatus further comprises an electromagnetic contactor with trip and reset mechanism using two separate solenoid actuators that are driven by triacs which are switched by optically-coupled triacs, or optocouplers.

10. The apparatus of claim 1, wherein said apparatus'"'"' miswire circuitry satisfies the requirements for miswire protection by the applicable UL standards.

11. The apparatus of claim 1, wherein said microprocessor is from the 80051 (also popularly known as 8051) 8-bit family of microcontrollers/microprocessors particularly the NXP P89LPC935 or P89LPC936, or could alternatively be substituted by NXP P89LPC9351 or P89LPC936,1 which have similar peripherals as the NXP P89LPC935 or P89LPC936 with expanded capabilities, and with operating speed to meet the sampling requirements of arc fault detection for said apparatus.

12. The apparatus of claim 1, wherein the configuration of a set of peripherals of said microprocessor to perform sampling to support coherent Direct Fourier Transforms and use their properties to compute and detect arc then disengage the contacts between the line and load side of said apparatus when an arc is present, and the configuration of a set of peripherals of said microprocessor to generate the timing signal required for coherent sampling of Direct Fourier Transforms, the use of microprocessors of the same peripherals, type, form, properties, characteristics and specifications as the microprocessors of said apparatus, from sources other than NXP.

13. The apparatus of claim 1, wherein said apparatus is provided with miswire protection circuitry having miswire code and said miswire protection circuitry also applying to Ground Fault Circuit Interrupters and similar electrical fault protective devices, as well as electrical systems for other applications requiring such protection, and when miswire condition occurs, the microprocessor activates the tripping mechanism to interrupt the circuit, and said miswire protection circuitry comprising 2 similar bridge circuits on line and load sides said apparatus with common connection to said automatic power switcher circuitry, and said miswire protection circuitry allowing reversibility of connections to load and line of said apparatus with code modification.

14. The apparatus of claim 1, wherein the determination or measurement of contactor position for miswire condition is done after the peak of the AC line sine wave where at that point, the contactor position has changed and signal voltage on the load side is either existent or not according to the switched position, and said miswire circuitry will apply to said apparatus on electrical systems with fundamental frequency of 60 Hz as well as other than 60 Hz, and with code modification to adjust hardware timing to the new frequency, and the hardware timing is set up for automatic response to line frequency changes, and the provision of visual and/or audible indicator/s to indicate the occurrence of miswire condition on said apparatus.

15. A method for detecting series and parallel arc faults, overcurrent, overload, short circuit, ground and surge, in single or multi-phase electrical circuits, AC or DC, and then safely interrupting said circuit, said method comprising:

a housing, circuitry, line and load side terminals, Hall Effect Current Sensor, power supply or automatic power switcher circuit, anti alias filter, programmable gain amplifier, buffer amplifier, microprocessor, reset button, trip button, test button, electromagnetic contactor, contactor position sensing circuit, miswire circuitry, visual indicators, audible alarms, and the associated mechanical, electrical, electro-mechanical and electronic components and interconnections.

16. The method of claim 15, wherein said Hall Effect Current Sensor is an integrated circuit Hall Effect Current Sensor, having a Hall current drive, dynamic offset cancellation, gain and temperature coefficient adjustment, amplifiers, zero “

0”

current adjustment, analog and digital outputs, analog to digital converter.

17. The method of claim 15, wherein said method may be used in different types or forms, including receptacles, receptacle outlets, circuit breakers, portable, cord, modular or integrated as part of another electrical system, equipment or device.

18. The method of claim 15, wherein said method further comprises an electrical circuitry with associated code parameters that limits or eliminates the occurrence of nuisance tripping by distinguishing arcs from normal electrical load signatures that mimics that of an arc.

19. The method of claim 15, wherein said method further comprises a housing, circuitry, line and load side terminals, Hall Effect Current Sensor;

power supply or automatic power switcher circuit, anti alias filter, programmable gain amplifier, buffer amplifier, microprocessor, reset, test and trip buttons, electromagnetic contactor, contactor position switching circuit, visual indicators, audible alarms, and the associated mechanical, electrical, electro-mechanical and electronic components and interconnections.

20. The method of claim 15, where the Hall Effect Current Sensor therein further comprises a Hall current drive, dynamic offset cancellation, gain and temperature coefficient adjustment, amplifiers, zero “

0”

current adjustment, analog and digital outputs, an analog to digital converter, being power-driven and bi-directional, its output voltages being proportional to the current flow, having stable output offset voltage, having nearly zero magnetic hysteresis, and having ratiometric output from supply voltage, having additional circuit for detection of zero crossing, overcurrent or overload and other additional features that could be used for signaling and detection of arcs with other electrical faults.

21. The method of claim 15, wherein the automatic power switcher therein further comprises an input rectifier and filter, inverter/chopper and controller, high frequency transformer, output rectifier and filter, along with the necessary components and interconnections, and said automatic power switcher circuit being a Switch Mode Power Supply circuit, said switcher employing a high frequency transformer and power switcher Integrated Circuit which automatically adopts to the input voltage from a given range of 80-265 VAC to provide constant DC voltage output or multiple outputs to the power driven components of therein, said switcher minimizing internal heating in enclosed circuits with the use of high frequency transformers and microelectronic circuitry avoiding unnecessary conditioning systems and components, said switcher circuit providing stable DC output voltage regardless of fluctuations in the input voltage within the input voltage range of the device 80-265 VAC, said switcher circuit operating independently of the type of power source and is applicable for all configurations within the operating voltage range, i.e., Line-to-Line, Line-Neutral, with the same constant output DC voltage, said switcher circuit with the associated hardware and software program being an integral part of said method.

22. The method of claim 15, wherein the programmable gain amplifier therein, being used to maintain the signal amplitude of the output signal of the Hall Effect Current Sensor within a range suitable for Analog to Digital Conversion, as used in the detection of arc and other electrical faults, said programmable gain amplifer connecting the low input to the low output and both to the dc offset voltage allowing the AC component of the output signal from the Hall Effect Current Sensor to be amplified with variable gain while the DC component receives a constant gain, said programmable gain amplifier being Analog Devices, Inc.'"'"'s AD8231, said programmable gain amplifier being a low-drift digitally programmable instrumentation amplifier with programmable gains.

23. The method of claim 15, wherein said method further comprising an electromagnetic contactor with trip and reset mechanism using two separate solenoid actuators that are driven by triacs which are switched by optically-coupled triacs, or optocouplers.

24. The method of claim 15, wherein said method'"'"'s miswire circuitry satisfies the requirements for miswire protection by the applicable UL standards.

25. The method of claim 15, wherein said microprocessor is from the 80051 (also popularly known as 8051) 8-bit family of microcontrollers/microprocessors particularly the NXP P89LPC935 or P89LPC936, or could alternatively be substituted by NXP P89LPC9351 or P89LPC936,1 which have similar peripherals as the NXP P89LPC935 or P89LPC936 with expanded capabilities, and with operating speed to meet the sampling requirements of arc fault detection for said method.

26. The method of claim 15, wherein the configuration of a set of peripherals of said microprocessor to perform sampling to support coherent Direct Fourier Transforms and use their properties to compute and detect arc then disengage the contacts between the line and load side of said method when an arc is present, and the configuration of a set of peripherals of said microprocessor to generate the timing signal required for coherent sampling of Direct Fourier Transforms, the use of microprocessors of the same peripherals, type, form, properties, characteristics and specifications as the microprocessors of said method, from sources other than NXP.

27. The method of claim 15, wherein said method being provided with miswire protection circuitry having miswire code description and said miswire protection circuitry also applying to Ground Fault Circuit Interrupters and similar electrical fault protective devices, as well as electrical systems for other applications requiring such protection, and when miswire condition occurs, the microprocessor activates the tripping mechanism to interrupt the circuit, and said miswire protection circuitry comprising 2 similar bridge circuits on line and load sides said apparatus with common connection to said automatic power switcher circuitry, and said miswire protection circuitry allowing reversibility of connections to load and line of said method with code modification.

28. The method of claim 15, wherein the determination or measurement of contactor position for miswire condition is done after the peak of the AC line sine wave where at that point, the contactor position has changed and signal voltage on the load side is either existent or not according to the switched position, and said miswire circuitry will apply to said method on electrical systems with fundamental frequency of 60 Hz as well as other than 60 Hz, and with code modification to adjust hardware timing to the new frequency, and the hardware timing is set up for automatic response to line frequency changes, and the provision of visual and/or audible indicator/s to indicate the occurrence of miswire condition on said method.