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Current Unbalance Detection Circuit for Laser Pumps

IP.com Disclosure Number: IPCOM000090150D
Original Publication Date: 1969-Feb-01
Included in the Prior Art Database: 2005-Mar-05
Document File: 2 page(s) / 48K

Publishing Venue

IBM

Related People

Haskell, JW: AUTHOR

Abstract

This protective circuit detects any unbalance in currents supplied to a set of high-intensity lamps used to optically pump a scanlaser and, in the event of a current unbalance, shuts off lamp current. Five current monitoring transformers and rectifier filter combinations 1...5 are used to develop the reference and comparison voltages. All transformers T1...T5 are identical except for their primary windings. In order to provide the total lamp current reference value, the primary of transformer T1 has only three turns. The primaries of transformers T2...T5 associated with lamps L1...L4 have twelve turns to multiply the individual lamp current samples by a factor of four. The reference voltage source Vt is connected in series opposition to each of the four comparison voltages Va...

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Current Unbalance Detection Circuit for Laser Pumps

This protective circuit detects any unbalance in currents supplied to a set of high-intensity lamps used to optically pump a scanlaser and, in the event of a current unbalance, shuts off lamp current. Five current monitoring transformers and rectifier filter combinations 1...5 are used to develop the reference and comparison voltages. All transformers T1...T5 are identical except for their primary windings. In order to provide the total lamp current reference value, the primary of transformer T1 has only three turns. The primaries of transformers T2...T5 associated with lamps L1...L4 have twelve turns to multiply the individual lamp current samples by a factor of four. The reference voltage source Vt is connected in series opposition to each of the four comparison voltages Va...Vd so that in the event of perfect lamp current balance no net signal voltage appears at the transistor detector circuits. If an individual lamp current exceeds its normal of twenty-five percent of the total lamp current, the corresponding comparison voltage increases, causing a positive error signal to be applied to the detectors. Lamp current less than normal results in a negative signal being applied to the detectors. If the error signal amplitude exceeds the detector threshold, the appropriate relay closes, operating the proper indicator. At the same time the main line contactor 6 is operated to open the main circuit.

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