Low energy pulsing device and method for electrical system arc detection

• US 6,785,104 B2
• Filed: 03/05/2002
• Issued: 08/31/2004
• Est. Priority Date: 03/05/2002
• Status: Active Grant

• Current Assignee: Eaton Intelligent Power Limited (Eaton Corporation PLC.)
• Original Assignee: Eaton Corp. (Wisconsin) (Eaton Corporation PLC.)
• Inventors: Elms, Robert T., Tallman, David M.
• Primary Examiner(s): LEJA, RONALD W
• Application Number:
  US10/091,074
• Publication Number:
  US 20030169545A1
• Time in Patent Office: 910 Days
• Field of Search: 361/42-50, 324/520, 324/527, 324/528, 324/529, 324/531, 324/534, 324/536, 324/538, 324/541, 324/551
• US Class Current: 361/42
• CPC Class Codes: G01R 31/3277 of low voltage devices, e.g. domestic or industrial devices, such as motor protections, relays, rotation switches
• CPC Class Codes: H02H 1/0015 Using arc detectors
• CPC Class Codes: H02H 3/042 combined with means for locating the fault locating faults in cables G01R31/08
• CPC Class Codes: H02H 3/044 Checking correct functioning of protective arrangements, e.g. by simulating a fault for differential current circuit breakers H02H3/335

Abstract

A pulsing apparatus for an electrical system includes line and neutral terminals structured to input a nominal alternating current line voltage, a timing mechanism or circuit for generating a timing signal having a duty cycle from the line voltage; a transformer for transforming the line voltage to a stepped up voltage having the duty cycle; load and load neutral terminals; and an output circuit for outputting a current at about the stepped up voltage to the load and load neutral terminals. The stepped up voltage is greater than the line voltage and less than a rated voltage of the electrical system. The stepped up voltage is adapted to identify an arcing fault in the electrical system. The duty cycle limits an average value of the current to less than about 4 mA to about 6 mA.

Claims

1. A pulsing apparatus for an electrical system having a nominal voltage and a rated voltage, said pulsing apparatus comprising:

first terminals structured to input a first voltage, said first voltage being about said nominal voltage;

means for generating a signal from said first voltage, said signal having a duty cycle;

means for transforming said first voltage to a second voltage having said duty cycle;

second terminals;

means for outputting a current at about said second voltage to said second terminals,

wherein said second voltage is greater than said first voltage and less than said rated voltage, said second voltage being adapted to identify an arcing fault in said electrical system;

wherein said duty cycle limits an average value of said current to less than about 6 mA; and

wherein said first terminals are structured to input an alternating current voltage as said first voltage.

2. The pulsing apparatus as recited in claim 1 wherein said alternating current voltage is about 120 VAC_RMS.

3. A pulsing apparatus for an electrical system having a nominal voltage and a rated voltage, said pulsing apparatus comprising:

first terminals structured to input a first voltage, said first voltage being about said nominal voltage;

means for generating a signal from said first voltage, said signal having a duty cycle;

means for transforming said first voltage to a second voltage having said duty cycle;

second terminals;

means for outputting a current at about said second voltage to said second terminals,

wherein said second voltage is greater than said first voltage and less than said rated voltage, said second voltage being adapted to identify an arcing fault in said electrical system;

wherein said duty cycle limits an average value of said current to less than about 6 mA; and

wherein said first voltage is an alternating current voltage having a plurality of cycles; and

wherein said duty cycle includes an on period and an off period.

4. The pulsing apparatus as recited in claim 3 wherein said on period includes about one percent of said cycles.

5. The pulsing apparatus as recited in claim 3 wherein said on period includes about two of said cycles and said off period includes about 178 of said cycles.

6. A pulsing apparatus for an electrical system having a nominal voltage and a rated voltage, said pulsing apparatus comprising:

first terminals structured to input a first voltage, said first voltage being about said nominal voltage;

means for generating a signal from said first voltage, said signal having a duty cycle;

means for transforming said first voltage to a second voltage having said duty cycle;

second terminals;

means for outputting a current at about said second voltage to said second terminals,

wherein said second voltage is greater than said first voltage and less than said rated voltage, said second voltage being adapted to identify an arcing fault in said electrical system;

wherein said duty cycle limits an average value of said current to less than about 6 mA; and

wherein said first voltage is about 120 VAC_RMS and wherein said second voltage is about 480 VAC _RMS.

7. A pulsing apparatus for an electrical system having a nominal voltage and a rated voltage, said pulsing apparatus comprising:

first terminals structured to input a first voltage, said first voltage being about said nominal voltage;

means for generating a signal from said first voltage, said signal having a duty cycle;

means for transforming said first voltage to a second voltage having said duty cycle;

second terminals;

means for outputting a current at about said second voltage to said second terminals,

wherein said second voltage is greater than said first voltage and less than said rated voltage, said second voltage being adapted to identify an arcing fault in said electrical system;

wherein said duty cycle limits an average value of said current to less than about 6 mA;

wherein said means for outputting comprises a resistor electrically connected in series with a capacitor, with the senses combination of said resistor and said capacitor being electrically connected between said means for transforming and one of said second terminals; and

wherein said means for outputting further comprises a second resistor electrically connected in parallel with said capacitor.

8. A method for identifying an arcing fault in an electrical system having a nominal voltage and a rated voltage, said method comprising the steps of:

inputting a first voltage, said first voltage being about said nominal voltage;

generating a signal from said first voltage, said signal having a duty cycle;

transforming said first voltage to a second voltage having said duty cycle, said second voltage being greater than said first voltage and less than said rated voltage, said second voltage being adapted to identify an arcing fault in said electrical system;

outputting a current at about said second voltage to said electrical system;

employing said duty cycle to limit an average value of said current to less than about 6 mA; and

further comprising inputting as said first voltage an alternating current voltage.

9. A method for identifying an arcing fault in an electrical system having a nominal voltage and a rated voltage, said method comprising the steps of:

inputting a first voltage, said first voltage being about said nominal voltage;

generating a signal from said first voltage, said signal having a duty cycle;

transforming said first voltage to a second voltage having said duty cycle, said second voltage being greater than said first voltage and less than said rated voltage, said second voltage being adapted to identify an arcing fault in said electrical system;

outputting a current at about said second voltage to said electrical system;

employing said duty cycle to limit an average value of said current to less than about 6 mA;

further comprising inputting as said first voltage about 120 VAC_RMS; and

outputting as said second voltage about 480 VAC_RMS.

10. A method for identifying an arcing fault in an electrical system having a nominal voltage and a rated voltage, said method comprising the steps of:

inputting a first voltage, said first voltage being about said nominal voltage;

generating a signal from said first voltage, said signal having a duty cycle;

transforming said first voltage to a second voltage having said duty cycle, said second voltage being greater than said first voltage and less than said rated voltage, said second voltage being adapted to identity an arcing fault in said electrical system;

outputting a current at about said second voltage to said electrical system;

employing said duty cycle to limit an average value of said current to less than about 8 mA;

further comprising transforming said first voltage to about 480 VAC_RMS; and

limiting said average value of said current to about 2.8 mA.