Method to predict a usable life of a vacuum interrupter in the field

1. A method for predicting a usable life of a vacuum interrupter, the method comprising:

placing a flexible magnetic field coil around an installed vacuum interrupter;

generating a DC potential to cross a first gap in the installed vacuum interrupter between a vapor shield in the installed vacuum interrupter and a contact assembly in the installed vacuum interrupter;

measuring ion current flow across the first gap using the flexible magnetic field coil;

indicating a selected tube type for the installed vacuum interrupter;

associating an ionic or current versus pressure calibration curve with the selected tube type;

applying the DC potential across the first gap in the installed vacuum interrupter;

forming a magnetic field around the installed vacuum interrupter using the flexible magnetic field coil;

creating the ion current flow across the first gap of the installed vacuum interrupter;

measuring a quantity of ions travelling across the first gap to compare the ion current flow before the first gap to ion current flow after the first gap;

calculating a pressure based on a difference in measured quantity of ions flowing across the first gap;

positioning the calculated difference in measured quantity of ions flowing across the first gap on an ionic or current versus pressure calibration curve for the installed vacuum interrupter from a library of ionic or current versus pressure calibration curves;

determining anticipated life expectancy of the installed vacuum interrupter; and

replacing the installed vacuum interrupter with a replacement vacuum interrupter as a function of the anticipated life expectancy of the installed vacuum interrupter.

2. A method comprising:

placing a magnetic field generator adjacent to a vacuum interrupter, thereby causing iron current flow in the vacuum interrupter;

measuring the ion current flow across a first gap in the vacuum interrupter using the magnetic field generator;

measuring a quantity of ions travelling across the first gap to compare the ion current flow before the first gap to ion current flow after the first gap;

calculating a pressure based on a difference in measured quantity of ions flowing across the first gap;

positioning the calculated difference in measured quantity of ions flowing across the first gap on an ionic or current versus pressure calibration curve for the vacuum;

determining an anticipated life expectancy of the vacuum interrupter as a function of the positioning; and

replacing the vacuum interrupter with a replacement vacuum interrupter as a function of the anticipated life expectancy of the vacuum interrupter.

3. The method of claim 2 , further comprising associating comprises associating an ionic or current versus pressure calibration curve with a type of tube for the installed vacuum interrupter.

4. The method of claim 3 , further comprising selecting the type of tube for the installed vacuum interrupter prior to the associating.

5. The method of claim 4 , wherein positioning comprises positioning the calculated difference in measured quantity of ions flowing across the first gap on an ionic or current versus pressure calibration curve for the installed vacuum interrupter from a library of ionic or current versus pressure calibration curves.

6. The method of claim 2 , wherein the magnetic field generator comprises a magnetic field coil, and further comprising placing the magnetic field coil around an installed vacuum interrupter.

7. The method of claim 6 , further comprising generating a DC potential to cross the first gap in the installed vacuum interrupter to thereby form the magnetic field around the installed vacuum interrupter.

8. The method of claim 7 , further comprising creating the ion current flow across the first gap of the installed vacuum interrupter.