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Browse Prior Art Database

Infrared Lamp Power Controller

IP.com Disclosure Number: IPCOM000074218D
Original Publication Date: 1971-Mar-01
Included in the Prior Art Database: 2005-Feb-23
Document File: 2 page(s) / 13K

Publishing Venue

IBM

Related People

Trotter, RR: AUTHOR

Abstract

In order to limit diffusion of heat into the work in soldering applications, it may be desirable to operate a tungsten-filament quartz infrared lamp on a short power cycle, such as from one to ten seconds. However, this subjects the lamp and its input control switching components to repetitive surges in inrush current unless steps are taken to limit current when power is first applied at the beginning of each cycle.

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This is the abbreviated version, containing approximately 53% of the total text.

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Infrared Lamp Power Controller

In order to limit diffusion of heat into the work in soldering applications, it may be desirable to operate a tungsten-filament quartz infrared lamp on a short power cycle, such as from one to ten seconds. However, this subjects the lamp and its input control switching components to repetitive surges in inrush current unless steps are taken to limit current when power is first applied at the beginning of each cycle.

Lamp 10 is supplied from AC power terminals 12, 14 through a pair of silicon- controlled rectifiers 16, 18 which are provided with phase-control firing modules 20, 22 having a common RC firing delay circuit 24, 26. Circuit 24, 26 operates to delay variably the firing of whichever of 16, 18 is forward biased by AC power applied at terminals 12, 14.

Circuit 24, 26 has START and RUN modes of operation. In the START mode, adjustable resistor 28 and capacitor 30 form the RC phase-control circuit, and in the RUN mode adjustable resistor 32 is substituted into this circuit. Resistor 28 is adjusted to effect a greater delay in the firing of SCR's 16, 18 when it has control and resistor 32 is adjusted for earlier firing of 16, 18 when it controls the RC circuit. When circuit 24, 26 is open, firing modules 20, 22 do not operate at all and no power is delivered through 16, 18 to lamp 10.

To start a lamp operation cycle, push button 34 is closed to connect control power from terminals 36, 38, through normally closed reset contactor 40, to start and LATCH relay coil 42. This actuates contactor 44 to bypass push button 34 and also actuates contactor 46. Closure of 46 completes a circuit from line 24 through resistor 28, normally closed con...