Browse Prior Art Database

Improved Approach to High Voltage Breakdown Testing

IP.com Disclosure Number: IPCOM000043540D
Original Publication Date: 1984-Sep-01
Included in the Prior Art Database: 2005-Feb-04
Document File: 2 page(s) / 35K

Publishing Venue

IBM

Related People

Carpenter, PC: AUTHOR

Abstract

The illustrated circuit conducts a simple, automatic continuity test of a product's primary circuit prior to the test for dielectric breakdown. This precludes the acceptance of a product as having passed its dielectric test when, due to an open primary, the test had never actually been applied. With specific reference to the drawing, a product to be tested is plugged into the outlet and the door of the safety enclosure is closed, making a circuit from a 110 VAC source through RLY2-1(N/C), through the product's primary circuit, RLY2-2(N/C), the photomod, and back to the 110 VAC line through the door switch. The two 51K resistors are provided to prevent an internally ground shorted product from receiving AC power. The photomod maintains a high impedance in series with the product.

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Improved Approach to High Voltage Breakdown Testing

The illustrated circuit conducts a simple, automatic continuity test of a product's primary circuit prior to the test for dielectric breakdown. This precludes the acceptance of a product as having passed its dielectric test when, due to an open primary, the test had never actually been applied. With specific reference to the drawing, a product to be tested is plugged into the outlet and the door of the safety enclosure is closed, making a circuit from a 110 VAC source through RLY2-1(N/C), through the product's primary circuit, RLY2-2(N/C), the photomod, and back to the 110 VAC line through the door switch. The two 51K resistors are provided to prevent an internally ground shorted product from receiving AC power. The photomod maintains a high impedance in series with the product. The internal impedance of the product is of little consequence and a wide range of products, including those using switching power supplies, can be tested. Activation of the photomod reduces the resistance of its internal photoresistor causing RLY1 to pick. RLY2 will pick through RLY1-1 (N/0) providing a path to ground is complete through the product's chassis, internal grounding, line cord and ground pin. RLY3 (N/0) holds RLY1 after RLY2 picks. Picking RLY2 allows the high voltage to flow through the product and the dielectric test to be thus carried out.

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