Square D Company

Leroy J Herbst

Michael W Knight

A method for laminating a magnetic core of a three-phase current transformer uses a continuous length of magnetic metal material and a mandrel having first, second, third, and fourth sets of pins mounted to a mandrel plate. The second and third pin sets are located adjacent one another, adjacent the respective first and fourth pin sets, and between the first and fourth pin sets. The third and fourth pin sets are movable between a retracted position within the mandrel plate and an extended position extending from the mandrel plate. The third and fourth pin sets are first positioned in the retracted position, and a first portion of the length of magnetic material is wound about the first and second pin sets to form the first phase section of the magnetic core. After moving the third pin set to the extended position, a second portion of the length of magnetic material is wound about the first and third pin sets to form the second phase section. After moving the fourth pin set to the extended position, a third portion of the length of magnetic material is wound about the first and fourth pin sets to form the third phase section, thereby forming the magnetic core. In another lamination method, each phase section is separately formed by continuously winding a respective length of magnetic metal material about a respective rotating mandrel. The magnetic core is formed by connecting the separately laminated phase sections.

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Raleigh, NC, United States of America

Leroy J Herbst