Method of preparing epoxy coated bus bars for use in electrical distribution equipment

Patent metadata

Field	Value
Publication number	US-11508495-B2
Application number	US-201715842037-A
Country	US
Kind code	B2
Filing date	Dec 14, 2017
Priority date	Dec 14, 2017
Publication date	Nov 22, 2022
Grant date	Nov 22, 2022

Abstract

An automated process for producing exposed electrical contact areas on the conductor part of an epoxy coated bus bar. When the epoxy coating is in the glassy state, one can safely and economically, preferably via automated apparatus, put the epoxy into the rubbery state by positioning the bar and applying localized heat at a select area of the coating; monitoring the heating to above the glass transition temperature of the epoxy, bringing cutting tools into contact with the epoxy for cutting and removing the rubbery coating away from the bus bar, and cooling the bus bar to bring adjacent coating back to the glassy state, thereby leaving an exposed electrical contact area of conductor on the bus bar with little or no surface damage.

First claim

The invention claimed is:

1. A method of preparing epoxy coated bus bars for use in electrical distribution equipment comprising:
coating an uninsulated surface of a bus bar conductor with a coating of insulating epoxy that is a crystalline solid which can exist in two states, a glassy state when below its glass transition temperature and a rubbery state when above its glass transition temperature, and letting the coating of insulating epoxy harden to the glassy state on the surface of the bus bar conductor;
applying a localized induction heating to the bus bar conductor in a subject area of the hardened coating of insulating epoxy until a temperature of the coating of the hardened insulating epoxy on the surface of the bus bar conductor in the subject area is at or above its glass transition temperature and the subject area of the coating of insulating epoxy is in the rubbery state, to avoid burning the epoxy;
delaminating the coating of insulating epoxy in the rubbery state from the surface of the bus bar conductor in the subject area;
cutting the subject area of the coating of rubbery insulating epoxy from the layer of epoxy remaining on the bus bar by bringing cutting tools into contact with the coating of rubbery insulating epoxy while at or above its glass transition temperature;
mechanically disassociating the subject area of the coating of rubbery insulating epoxy from the surface of the bus bar conductor by drawing the cutting tools along a length of the bus bar conductor in the subject area to pull the coating of rubbery insulating epoxy free of the bus bar conductor and from the remaining layer of epoxy adjacent to the subject area and removing the coating of rubbery insulating epoxy of the subject area from the bus bar conductor based on heat retention by the bus bar from the induction heating, to create an exposed electrical contact area; and
allowing the epoxy coated bus bar with the electrical contact area to cool below the glass transition temperature to reharden any epoxy coating at a boundary of the electrical contact area.

2. The method of preparing epoxy coated bus bars for use in electrical distribution equipment of claim 1 , further comprising: monitoring the temperature of the subject area while the localized heating is applied.

3. The method of preparing epoxy coated bus bars for use in electrical distribution equipment of claim 1 , wherein the heating, cutting, and removing are accomplished by automated apparatus.

4. The method of preparing epoxy coated bus bars for use in electrical distribution equipment according to claim 1 wherein the subject area is a bus bar end, and the rubbery epoxy is removed from all sides of the bus bar end.

5. The method of preparing epoxy coated bus bars for use in electrical distribution equipment according to claim 1 wherein the application of heat is done through induction heaters.

6. A method of creating electrical contact areas on a bus bar coated with hardened insulating epoxy wherein the epoxy is in a glassy state, comprising:
wherein the insulating epoxy is a crystalline solid which can exist in two states, the glassy state when below its glass transition temperature and a rubbery state when above its glass transition temperature;
putting the coating of hardened insulating epoxy into the rubbery state via automated means positioning the bus bar, by applying a localized induction heating to the bus bar conductor at a select area of the insulating epoxy coating until a temperature of the coating of the hardened insulating epoxy in the select area on the surface of the bus bar conductor is at or above its glass transition temperature, to avoid burning the coating of insulating epoxy;
monitoring the heating to above the glass transition temperature of the coating of insulating epoxy;
delaminating the coating of insulating epoxy in the rubbery state from the surface of the bus bar conductor in the select area;
bringing cutting tools into contact with the insulating epoxy while above the glass transition temperature for cutting the select area of the insulating epoxy away from the bus bar;
mechanically disassociating the select area of rubbery state insulating epoxy from the surface of the bus bar conductor by drawing the cutting tools along a length of the bus bar conductor in the select area to pull the coating of rubbery insulating epoxy free of the bus bar conductor and from a remaining layer of epoxy adjacent to the select area and removing the coating of the rubbery insulating epoxy of the select area away from the bus bar conductor based on heat retention by the bus bar from the induction heating, to create an exposed electrical contact area, and;
cooling the epoxy coated bus bar to bring coating adjacent to the contact area back to a glassy state, thereby leaving an exposed electrical contact area of conductor on the bus bar.

7. A method of preparing epoxy coated bus bars for use in electrical distribution equipment comprising:
coating surfaces of first and second sides of an uninsulated bus bar conductor with a coating of insulating epoxy that is a crystalline solid which can exist in two states, a glassy state when below its glass transition temperature and a rubbery state when above its glass transition temperature, and letting the coating of insulating epoxy harden to the a glassy state on the surfaces of first and second sides of the bus bar conductor;
applying a localized induction heating to the first and second sides of the bus bar conductor in a subject area of the hardened coating of insulating epoxy until a temperature of the subject area of the coating of hardened insulating epoxy on the surface of the bus bar conductor is at or above its glass transition temperature and the subject area of the coating of insulating epoxy is in the a rubbery state to avoid burning the epoxy;
delaminating the coating of insulating epoxy in the rubbery state from the surfaces of first and second sides of the bus bar conductor in the subject area;
cutting the subject area of the coating of rubbery insulating epoxy from the layer of epoxy remaining on the first and second sides of the bus bar by bringing cutting tools located on the first and second sides of the bus bar, into contact at substantially the same time with the coating of rubbery insulating epoxy while at or above its glass transition temperature;
mechanically disassociating the subject area of the coating of rubbery insulating epoxy from the surfaces of first and second sides of the bus bar conductor by drawing the cutting tools along a length of the bus bar conductor in the subject area to pull the coating of rubbery insulating epoxy free of the surfaces of first and second sides of the bus bar conductor and from a remaining layer of epoxy adjacent to the subject area and removing the coating of rubbery insulating epoxy of the subject area from the first and second sides of the bus bar conductor based on heat retention by the bus bar from the induction heating, to create an exposed electrical contact area; and
allowing the epoxy coated bus bar with the electrical contact area to cool below the glass transition temperature to reharden any epoxy coating at the boundary of the electrical contact area.

Assignees

• Schneider Electric Usa Inc

Inventors

• Wittwer John A

Classifications

• B05D3/0218

  Pretreatment, e.g. heating the substrate · CPC title

• H01R43/28

  for wire processing before connecting to contact members, not provided for in groups H01R43/02 - H01R43/26 · CPC title

• H02G1/1273

  by pushing backwards insulation · CPC title

• H01B13/06

  Insulating conductors or cables (H01B13/32 takes precedence) · CPC title

• B05D1/24

  Applying particulate materials · CPC title