Abstract: A visible erosion indicator is provided to determine the condition of contacts inside a vacuum interrupter. The visual indicator is located on a portion of an extension of the moveable contact drive stem which is a threaded stud. The indicator is formed from a flexible member that is screwed onto the stud until a given extent of the flexible member protrudes beyond the bottom pan of the circuit breaker, that the moveable contact stem traverses during opening and closure of the internal contacts within the vacuum interrupter. The extension of the wear indicator is measured with the circuit breaker in the closed position to provide an accurate measure of contact wear. The flexible property of the wear indicator enables it to clear obstructions as the breaker drawer is moved within the breaker enclosure.

Abstract: A contact cleaning machine for removing particulates and other undesirable debris from the surfaces of articles moving along a curved path under the cleaning machine, without disturbing the orientation of the articles which cannot be clamped against movement. Cleaning is performed by a roller (22) which is mounted in the machine to roll across the tops of articles as they pass underneath. The peripheral surface (28) of the roller is coated with a tacky adhesive to lift off the undesirable particles. To avoid the roller applying differential forces to the article, the roller is made conical and convergent towards the axis of curvature of the path followed by the article. The avoidance of differential forces on the unclamped articles eliminates any tendency for the cleaning roller to turn the articles.