Fabrication process to produce a toroidal current transformer

Patent metadata

Field	Value
Publication number	US-11152152-B2
Application number	US-201816207572-A
Country	US
Kind code	B2
Filing date	Dec 3, 2018
Priority date	Dec 3, 2018
Publication date	Oct 19, 2021
Grant date	Oct 19, 2021

Abstract

The present disclosure relates to a fabrication process for a current transformer. For example, the process may include wrapping first windings around a first core half of a magnetic core of a current transformer. The process may include wrapping second windings around a second core half of the magnetic core. The magnetic core may be inserted into an overmold tool. The process may include overmolding a first overmold over the first core half of the magnetic core and a second overmold over the second core half of the magnetic core. After overmolding, the magnetic core may be cut in half.

First claim

What is claimed is:

1. A method, comprising:
wrapping first windings around a first core half of a magnetic core of a current transformer;
wrapping second windings around a second core half of the magnetic core;
after wrapping the first windings around the first core half and the second windings around the second core half, inserting the magnetic core into an overmold tool;
overmolding a first overmold over the first core half of the magnetic core and the first windings and a second overmold over the second core half of the magnetic core and the second windings, wherein the first overmold and the second overmold secure the first core half and the second core half within housings of the current transformer, wherein overmolding the first core half and the second core half while the magnetic core is a single piece ensures alignment of the first core half with the second core half throughout the overmold process; and
after overmolding, cutting the magnetic core in half.

2. The method of claim 1 , comprising waiting for a mold material to set prior to cutting the magnetic core in half.

3. The method of claim 1 , comprising maintaining a position of the magnetic core using alignment features on the overmold to cut the magnetic core in half.

4. The method of claim 3 , comprising installing the first core half within a first housing of a faulted circuit indicator (FCI) by engaging a first set of the alignment features with corresponding recesses of the first housing.

5. The method of claim 4 , comprising installing the second core half of the current transformer (CT) within a second housing of a faulted circuit indicator (FCI), different from the first housing, by engaging a second set of the alignment features with corresponding recesses of the second housing.

6. The method of claim 1 , wherein overmolding the magnetic core comprises molding a cavity that forms a first gap on a first end between the first core half and the second core half and a second gap on a second end, opposite the first end, between the first core half and the second core half to allow cutting across a diameter of the magnetic core.

7. The method of claim 1 , comprising electrically connecting the current transformer (CT) to fault detection circuitry via lead cables attached to ends of the first windings and the second windings of the CT.

8. A method, comprising:
wrapping first windings around a first core half of a magnetic core of a current transformer;
wrapping second windings around a second core half of the magnetic core;
inserting the magnetic core into an overmold tool after wrapping the first windings around the first core half and the second windings around the second core half;
upon inserting the magnetic core into the overmold tool, overmolding a first overmold over the first core half of the magnetic core and a second overmold over the second core half of the magnetic core with a first gap on a first end between the first core half and the second core half and a second gap on a second end, opposite the first end, between the first core half and the second core half to allow cutting across a diameter of the magnetic core within the first gap and the second gap, wherein the first overmold and the second overmold secure the first core half and the second core half of the magnetic core within housings of the current transformer, and wherein overmolding the first core half and the second core half while the magnetic core is a single piece ensures alignment of the first core half with the second core half throughout the overmold process;
after overmolding, cutting the magnetic core in half across the diameter of the overmold.

9. A method, comprising:
wrapping first windings around a first core half of a magnetic core of a current transformer;
wrapping second windings around a second core half of the magnetic core;
after wrapping the first windings around the first core half and the second windings around the second core half, inserting the magnetic core into an overmold tool;
overmolding a first overmold over the first core half of the magnetic core and a second overmold over the second core half of the magnetic core while the magnetic core is a single piece to ensure alignment of the first core half with the second core half throughout the overmold process, wherein the first overmold and the second overmold secure the first core half and the second core half within housings of the current transformer;
after overmolding, cutting the magnetic core in half.

Assignees

• Schweitzer Engineering Lab Inc

Inventors

• Thomas Mark A
• Ryan Eric
• Kenny David

Classifications

• H01F2038/305

  with toroidal magnetic core · CPC title

• H01F30/16

  Toroidal transformers · CPC title

• H01F41/026

  protecting methods against environmental influences, e.g. oxygen, by surface treatment (magnetic particles with skin H01F1/061, H01F1/09, H01F1/24, H01F1/33 and G11B5/706) · CPC title

• H01F27/02

  Casings · CPC title

• H01F41/0286

  Trimming · CPC title