Cylindrical coil and contact support for vacuum interrupter

A vacuum interrupter, comprising:

• a vacuum envelope;
• first and second electrode assemblies defining a common longitudinal axis within the vacuum envelope;
• first and second terminal posts each having a longitudinal axis electrically coupled to the first and second electrode assemblies, respectively, for coupling the first and second electrode assemblies to an a.c. circuit;
• first means permitting movement of at least one of the electrode assemblies axially of the other between an open circuit position and an in series closed circuit position;
• wherein each of the first and second electrode assemblies include:
• a contact having a contacting surface confronting the other contact and a rear surface spaced therefrom;
• a generally annular-shaped electrode coil member defining a current path extending in a substantially circumferential direction less than 360.degree. around the generally annular-shaped electrode coil member, comprising a first end proximate the contacts, an annular second end proximate the terminal post, a peripheral surface, an interior surface, and oriented substantially in parallel with said longitudinal axis of said first and second terminal parts, and extending in an axial direction from the first end to a first axial position at a first polar angle .phi.1, a circumferential slot at the first axial position extending radially between the interior surface and the peripheral surface and extending in an angular direction form .phi.1 to a second polar angle .phi.2 substantially spaced from .phi.1, said annular second end being substantially solid between said terminal post and said interior surface, said region between said terminal post and said interior surface having a radial dimension, said annular-shaped current member having an axial length which is substantially larger than said radial dimension, wherein the axial slot and the circumferential slot define a circumferential first coil extending from a first end at about .phi.2 to a second end at about .phi.1;
• second means for electrically coupling the rear surface of the contact to the second end of the first coil;
• and
• third means for electrically coupling the terminal post to the electrode coil member at a second axial position proximate the annular second end of the electrode coil member and spaced from the first axial position, said annular second end of the annular-shaped electrode coil member comprising a substantially cylindrical inner surface rigidly coupled to a substantially cylindrical outer surface of the terminal post.

A method of producing a circumferential electrode coil for electrically coupling a terminal post with a longitudinal axis to a contact in a vacuum interrupter defining a current path extending in a substantially circumferential direction less than 360.degree. around the circumferential electrode coil, fabricated by the steps of:

• providing a generally cylindrical metal tube that includes first and second ends, a peripheral surface, and an interior surface having a first radius;
• boring the interior surface a bore length to a third radius from the first end to a first axial position;
• boring the interior surface to a second radius from the second end to a stop surface at a second axial position between the second end and the first axial position for insertion of the terminal post up to the stop surface, the difference between said second radius and said third radius being substantially less then said bore length;
• cutting a first circumferential slot at about the first axial position from a first angular position .phi.1 to a second angular position .phi.2 and from the peripheral surface to the third radius;
• and
• cutting a first axial slot which is oriented substantially in parallel with said longitudinal axis of said terminal part from the first end to the first circumferential slot from the peripheral surface to the third radius at the first angular position .phi.1.