Transformer winding resistance tester test probe and method
View Patent ↗A test probe has a probe portion, a current source lead attachment portion and a voltage sense lead attachment portion. The test probe includes two conductive halves secured together with an electrically insulating material disposed between the halves electrically insulating them from each other. Each half has an “L” shape including a probe portion and a test lead attachment portion extending perpendicularly outwardly from the probe portion, and provides the test probe with an overall “T” shape. The conductive halves can be made of copper-beryllium. Methods of providing and using the test probe can include uncoupling a male coupling member of a power cable connector of a loadbreak bushing assembly from a female coupling member of the loadbreak bushing and inserting the rod-shaped probe portion into the female coupling member.
1. A loadbreak bushing test probe for testing a transformer winding resistance comprising:
a rod-shaped probe portion comprising a first conductive half coupled to a second conductive half with an electrically insulating material disposed between the conductive halves and insulating the conductive halves from each other;
a current source lead attachment portion coupled to and extending from a first end of the first conductive half of the rod-shaped probe portion;
a voltage sense lead attachment portion coupled to and extending from a first end of the second conductive half of the rod-shaped probe portion; and
an insulating tip surrounding a distal end of the first conductive half and a distal end of the second conductive half;
wherein the rod-shaped probe portion has a diameter that substantially corresponds to a diameter of a female connecter of the loadbreak bushing.
2. The loadbreak bushing test probe according to claim 1 , wherein the current source lead attachment portion and the voltage sense lead attachment portion extend away from each other.
3. The loadbreak bushing test probe according to claim 1 , wherein the current source lead attachment portion and the voltage sense lead attachment portion extend away from each other and in a common plane.
4. The loadbreak bushing test probe according to claim 1 , wherein the current source lead attachment portion and the voltage sense lead attachment portion extend perpendicular to the rod-shaped probe portion and away from each other in a common plane such that the test probe has an overall T-shaped configuration.
5. The loadbreak bushing test probe according to claim 1 , wherein at least the first and second conductive halves of the rod-shaped probe portion are comprised of copper-beryllium.
6. The loadbreak bushing test probe according to claim 1 , further comprising a current source lead electrically coupled to the current source lead attachment portion and a voltage sense lead electrically coupled to the voltage sense lead attachment portion.
7. The loadbreak bushing test probe according to claim 1 , further comprising a non-conductive screw passing through aligned apertures in the first and second conductive halves respectively, and a nut threaded onto the non-conductive screw.
8. The loadbreak bushing test probe according to claim 7 , wherein the insulating tip operates to couple the distal end of the first conductive half to the distal end of the second conductive half.
9. A method of testing a winding resistance of a transformer having a loadbreak bushing comprising:
providing a test probe comprising a rod-shaped probe portion comprising a first conductive portion that is electrically insulated from a second conductive portion;
providing the rod-shaped portion with an overall diameter that corresponds to a diameter of a male connector member of a power cable connector that cooperates with a female connector of the loadbreak bushing;
electrically coupling a current source lead from a resistance tester to only the first conductive portion; and
electrically coupling a voltage sense lead from the resistance tester to only the second conductive portion.
10. The method according to claim 9 , further comprising providing indicia instructing a user to insert the rod-shaped probe portion into the female connector of the loadbreak bushing.
11. The method according to claim 9 , wherein providing the test probe comprises providing each of the first and second conductive portions as elongated members having a semi-circular cross-sectional shape.
12. The method according to claim 9 , further comprising providing the test probe with a current source lead attachment portion extending from a proximal end of the first conductive portion, and providing the test probe with a voltage sense lead attachment portion extending from a proximal end of the second conductive portion, wherein the current source lead attachment portion extends away from the voltage sense lead attachment portion; and wherein electrically coupling the current source lead to the first conductive portion comprises coupling the current source lead to the current source lead attachment portion, and wherein electrically coupling the voltage sense lead to the second conductive portion comprises coupling the voltage sense lead to the voltage sense lead attachment portion.
13. The method according to claim 9 , further comprising forming at least the first and second conductive portions of the test probe from a copper-beryllium material.
14. The method according to claim 9 , wherein providing the test probe further comprises securing an electrically insulating material between the first and second conductive portions.
15. The method according to claim 9 , wherein providing the test probe further comprises providing a nonconductive fastener through aligned openings adjacent a proximal end of the each of the first and second conductive portions respectively, and providing an insulating tip surrounding a distal end of the rod-shaped probe portion to couple a distal end of the first conductive portion to a distal end of a second conductive portion.
16. A method of testing a winding resistance of a transformer having a loadbreak bushing comprising:
providing a test probe comprising a rod-shaped probe portion comprising a first conductive portion that is electrically insulted from a second conductive portion
electrically coupling a current source lead to the first conductive portion;
electrically coupling a voltage sense lead to the second conductive portion;
uncoupling a male coupling member of a power cable connector from a female coupling member of the loadbreak bushing; and
inserting the rod-shaped probe portion into the female coupling member.
17. The method according to claim 16 , wherein providing the test probe further comprises providing each of the first and second conductive portions as elongated members having a semi-circular cross-sectional shape comprising the rod-shaped probe portion.
18. The method according to claim 16 , further comprising providing the test probe with a current source lead attachment portion extending from a proximal end of the first conductive portion, and providing the test probe with a voltage sense lead attachment portion extending from a proximal end of the first conductive portion, wherein the current source lead attachment portion extends away from the voltage sense lead attachment portion; and wherein electrically coupling the current source lead to the second conductive portion comprises coupling the current source lead to the current source lead attachment portion, and wherein electrically coupling the voltage sense lead to the second conductive portion comprises coupling the voltage sense lead to the voltage sense lead attachment portion.
19. The method according to claim 16 , further comprising forming at least the first and second conductive portions of the test probe from a copper-beryllium material.
20. The method according to claim 16 , wherein providing the test probe further comprises: securing an electrically insulating material between the first and second conductive portions; providing a nonconductive fastener through aligned openings adjacent a proximal end of the each of the first and second conductive portions respectively; and providing an insulating tip surrounding a distal end of the rod-shaped probe portion to couple a distal end of the first conductive portion to a distal end of the second conductive portion.