Controlled-energy electrical arc systems, methods, and apparatuses

Patent metadata

Field	Value
Publication number	US-9514917-B1
Application number	US-201314013933-A
Country	US
Kind code	B1
Filing date	Aug 29, 2013
Priority date	Aug 29, 2013
Publication date	Dec 6, 2016
Grant date	Dec 6, 2016

Abstract

Systems, methods, and apparatuses for triggering electrical arcs are disclosed. Such arcs are useful for testing combustible fluids and equipment operating near ignition hazards. Arcs may be produced with a defined energy at a defined time with little variation in arc energy. Consistent production of arcs is facilitated by one or more of conditioned electrodes, control and/or reduction of parasitic capacitance, avoidance of corona sources, and non-interfering arc triggers. Electrodes may be conditioned by repeated application of conditioning arcs. Conditioned electrodes have relatively physically consistent and chemically consistent tips. Arc triggers may be charged particle sources such as light sources operating in cooperation with a target to produce free electrons proximate the electrodes.

First claim

The invention claimed is:

1. A method of generating a controlled arc in a component test system, comprising:
conditioning a first electrode tip that is bare metal and a second electrode tip that is bare metal to produce a consistent roughness and a consistent surface chemical composition on each of the first electrode tip and the second electrode tip, wherein the conditioning includes repeatedly applying a conditioning arc across an electrode gap delimited by the first electrode tip and the second electrode tip such that a discharge arc across the electrode gap does not significantly alter the roughness of the first electrode tip and the roughness of the second electrode tip, wherein the discharge arc has an energy of about 200 μJ;
storing, after the conditioning, stored energy in a capacitor to be discharged across the electrode gap; and
discharging, after the storing, an arc with an arc energy across the electrode gap, wherein the discharging includes triggering the arc at a defined time, wherein the triggering contributes less than 10% to the arc energy, and wherein the arc energy is substantially the same as the stored energy.

2. A method of generating a controlled arc in a component test system, comprising:
conditioning a first electrode tip that is bare metal and a second electrode tip that is bare metal to produce a consistent roughness and a consistent surface chemical composition on each of the first electrode tip and the second electrode tip, wherein the conditioning includes repeatedly applying a conditioning arc with a conditioning energy across an electrode gap delimited by the first electrode tip and the second electrode tip until a relative standard deviation in the conditioning energy is less than 5%, and wherein the conditioning includes conditioning the first electrode tip and the second electrode tip such that a discharge arc across the electrode gap does not significantly alter the roughness of the first electrode tip and the roughness of the second electrode tip, wherein the discharge arc has an energy of about 200 μJ; and
discharging, after the conditioning, an arc with an arc energy across the electrode gap, wherein the electrode gap is 0.5-10 mm.

3. The method of claim 2 , wherein the conditioning includes repeatedly applying more than 100 conditioning arcs between the first electrode tip and the second electrode tip.

4. The method of claim 2 , wherein the conditioning energy is less than 1,000 μJ.

5. The method of claim 2 , wherein the electrode gap is delimited at less than 5 mm.

6. The method of claim 2 , wherein the discharging includes discharging about 200 μJ, across the electrode gap.

7. The method of claim 2 , further comprising:
storing stored energy in a capacitor to be discharged across the electrode gap, wherein the stored energy is substantially the same as the arc energy.

8. The method of claim 2 , further comprising:
applying an electrode voltage across the electrode gap before the discharging, wherein the electrode voltage is at least 5 kV.

9. The method of claim 2 , further comprising:
applying an electrode voltage across the electrode gap, wherein the electrode voltage is about 0-300 V less than a breakdown voltage of a medium spanning the electrode gap.

10. The method of claim 2 , further comprising:
repeating the discharging, wherein the arcs from the repeating have a relative standard deviation in arc energy of less than 20%.

11. The method of claim 2 , wherein the discharging includes triggering the arc at a defined time.

12. The method of claim 11 , wherein the triggering contributes less than 10% to the arc energy.

13. The method of claim 11 , wherein the triggering contributes less than 20 μJ to the arc energy.

14. The method of claim 2 , wherein the discharging includes discharging in the absence of corona sources.

15. A controlled-energy electrical arc source comprising:
a first electrode with a tip that is bare metal having a consistent roughness and a consistent surface chemical composition;
a second electrode with a tip that is bare metal having a consistent roughness and a consistent surface chemical composition, wherein the tip of the first electrode and the tip of the second electrode are spaced apart to delimit an electrode gap, wherein the tip of the first electrode and the tip of the second electrode are configured such that an arc across the electrode gap does not significantly alter the roughness of the tip of the first electrode and the roughness of the tip of the second electrode, wherein the arc has an energy of about 200 μJ; and
a discharge circuit consisting essentially of:
a capacitor to store a defined discharge energy at a defined discharge voltage, wherein the capacitor has a first terminal electrically connected to the first electrode and a second terminal electrically connected to the second electrode; and
an isolation resistor in series with the capacitor.

16. The controlled-energy electrical arc source of claim 15 , wherein the tip of the first electrode and the tip of the second electrode are configured such that an arc across the electrode gap does not significantly alter the surface chemical composition of the tip of the first electrode and the surface chemical composition of the tip of the second electrode, wherein the arc has an energy of about 200 μJ.

17. The controlled-energy electrical arc source of claim 15 , wherein the tip of the first electrode and the tip of the second electrode are configured to produce a series of arcs with a relative standard deviation in arc energy of less than 20%.

18. The controlled-energy electrical arc source of claim 15 , wherein the first electrode and the second electrode include tungsten.

19. The controlled-energy electrical arc source of claim 15 , wherein the controlled-energy electrical arc source has a net capacitance of less than 20 pF.

20. An aerospace component test system comprising:
a test chamber;
the controlled-energy electrical arc source of claim 15 , at least partially enclosed by the test chamber; and
a test sample at least partially enclosed by the test chamber.

Assignees

• Boeing Co

Inventors

• Mciver Carl Roy
• Kwon Eddie

Classifications

• H01J37/32064 Primary

  Circuits specially adapted for controlling the arc discharge (for plasma torches H01H1/36) · CPC title

• H05H1/52

  using exploding wires or spark gaps (H05H1/26 takes precedence) · CPC title