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Contact for Insulation Resistance Tester

IP.com Disclosure Number: IPCOM000090288D
Original Publication Date: 1969-Mar-01
Included in the Prior Art Database: 2005-Mar-05
Document File: 1 page(s) / 11K

Publishing Venue

IBM

Related People

Grobin, AW: AUTHOR [+3]

Abstract

An indium-mercury composition is used to provide a continuous contact with the insulating housing surrounding a component during the testing of terminal-to-case insulation resistance of the housing. Such a test is performed with respect to the housing or the case enclosing a component by shorting all the leads to the component and measuring the leakage current between the leads and an electrical conductor surrounding the housing. Where both aluminum foil and metal shot are used to provide contact with the insulating housing, such materials do not provide a uniform contact with the housing. On the other hand, when certain liquids which provide a uniform contact are used, other problems arise.

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Contact for Insulation Resistance Tester

An indium-mercury composition is used to provide a continuous contact with the insulating housing surrounding a component during the testing of terminal-to- case insulation resistance of the housing. Such a test is performed with respect to the housing or the case enclosing a component by shorting all the leads to the component and measuring the leakage current between the leads and an electrical conductor surrounding the housing. Where both aluminum foil and metal shot are used to provide contact with the insulating housing, such materials do not provide a uniform contact with the housing. On the other hand, when certain liquids which provide a uniform contact are used, other problems arise. Water, due to capillary action, tends to penetrate small openings in the insulation, often revealing failures which are of little interest to the user. Mercury, while providing an excellent contact, presents a safety hazard due to its toxicity. An excellent contact is provided by an indium-mercury composition. A composition containing from one to three percent of indium significantly reduces the toxicity without affecting the electrical properties of mercury.

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