Methods and systems for controlling the temperature stability of an inductor

1. A method of assembling a proximity probe including a coil, said method comprising:

determining a coil wire dimension and coil geometry for the probe such that a resistance versus temperature profile of the coil is approximately constant when the coil is excited with an excitation frequency of approximately 150 kilohertz to approximately 350 kilohertz; and

adjusting the coil geometry such that a resistance versus temperature profile of the coil is substantially constant.

2. A method in accordance with claim 1 wherein determining a coil wire dimension and coil geometry comprises determining a coil wire dimension and coil geometry for the probe such that a resistance versus temperature profile of the coil is approximately constant when the coil is excited with an excitation frequency of approximately 267 kilohertz.

3. A method in accordance with claim 1 wherein determining a coil wire dimension and coil geometry comprises selecting a coil geometry based on a distance range between the proximity probe and a target during operation.

4. A method in accordance with claim 1 wherein determining a coil wire dimension and coil geometry comprises selecting a coil wire dimension and a coil diameter.

5. A method in accordance with claim 1 wherein determining a coil wire dimension and coil geometry comprises selecting a coil wire dimension and a coil diameter to be approximately fifty millimeters.

6. A method in accordance with claim 1 wherein adjusting the coil geometry comprises adjusting at least one of the coil diameter and the number of wire turns in the coil.

7. A method in accordance with claim 1 wherein adjusting the coil geometry comprises changing the number of wire turns in the coil.

8. A method in accordance with claim 1 further comprising adjusting a scale factor of the coil to a predetermined value using a tuning disk magnetically coupled with the coil.

9. A method in accordance with claim 8 further comprising adjusting a scale factor of the coil to a predetermined value by changing a distance between the tuning disk and the coil.

10. A proximity probe configured to monitor a rotatable machine by measuring a gap between said probe and a target associated with the rotatable machine, said proximity probe comprising:

a coil configured to be located magnetically proximate the target on a first side of the coil, said coil comprising a coil wire dimension and coil geometry for the probe such that a resistance versus temperature profile of the coil is approximately constant when the coil is excited with an excitation frequency of approximately 150 kilohertz to approximately 350 kilohertz; and

a tuning disk positioned proximate a second opposite side of the coil;

wherein a distance between said first coil and tuning disk is changeable to generate a predetermined scale factor for the coil.

11. A proximity probe in accordance with claim 10 wherein said coil comprises a coil wire dimension and coil geometry for the probe such that a resistance versus temperature profile of the coil is approximately constant when the coil is excited with an excitation frequency of approximately 267 kilohertz.

12. A proximity probe in accordance with claim 10 wherein said coil includes a DC wire resistance and a proximity effect wire resistance resulting in a temperature dependent series resistance.

13. A proximity probe in accordance with claim 12 wherein said coil comprises a plurality of turns of wire and a geometry configured to facilitate reducing the temperature dependence of the coil when operated at a predetermined frequency.

14. A proximity probe in accordance with claim 10 wherein said coil comprises a plurality of turns of wire and a geometry based on a distance range between the proximity probe and a target during operation.

15. A proximity probe in accordance with claim 10 wherein said coil comprises a coil diameter of approximately fifty millimeters.

16. A system for determining a gap defined between an eddy current proximity probe and a target, said system comprising:

a proximity probe comprising:

a coil configured to be located magnetically proximate the target on a first side of the coil such that an output signal correlative to a distance between the proximity probe and the target, said coil comprising a coil wire dimension and a coil geometry for the probe such that a resistance versus temperature profile of the coil is approximately constant when the coil is excited with an excitation frequency of approximately 150 kilohertz to approximately 350 kilohertz; and

a tuning disk positioned proximate a second opposite side of the coil wherein a distance between said first coil and tuning disk is changeable to generate a predetermined scale factor for the coil; and

an electronic circuit coupled to said proximity probe configured to transmit an excitation frequency to said proximity probe and to receive the output signal from said proximity probe.

17. A system in accordance with claim 16 wherein said coil comprises a coil wire dimension and a coil geometry for the probe such that a resistance versus temperature profile of the coil is approximately constant when the coil is excited with an excitation frequency of approximately 267 kilohertz.

18. A system in accordance with claim 16 wherein said coil includes a DC wire resistance and a proximity effect wire resistance resulting in a temperature dependent series resistance.

19. A system in accordance with claim 18 wherein said coil comprises a plurality of turns of wire and a geometry configured to facilitate reducing the temperature dependence of the coil when operated at a predetermined frequency.

20. A system in accordance with claim 16 wherein said coil comprises a coil diameter of approximately fifty millimeters.