Regulating voltage through a filament transformer

Mar 15, 2005 4 Replies

I'm trying to build a resistance soldering unit using a filament Xfmr with 120V input and 6.5V 20A secondary. Any suggestions as to how I should regulate the input voltage so as to have variable output?(Without,hopefully, having to purchase a large VARIAC!) The input regulator will need to sustain the large current draw with no "'splosions"!



"rich brenz" schreef in bericht news:YFAZd.15233$ snipped-for-privacy@fe03.lga...

Some low voltage halogen lamps are powered by a transformer - a real transformer, not an SMPS - and some dimmers exist to control them. May be the best buy. Ordinairy incandescent dimmers won't work for long. Designing something to control the primary is not that easy, allthough it can be done off course. But maybe someone has a good design.

You can controll the secondary, but you will loose some voltage and 6.5V is not that much.

petrus bitbyter

Input current is about an amp. That's not a very large VARIAC!. mike

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Input current is about an amp. That's not a very large VARIAC!. mike

Return address is VALID but some sites block emails with links. Delete this sig when replying. . Wanted, PCMCIA SCSI Card for HP m820 CDRW. FS 500MHz Tek DSOscilloscope TDS540 Make Offer Wanted, 12.1" LCD for Gateway Solo 5300. Samsung LT121SU-121 Bunch of stuff For Sale and Wanted at the link below. MAKE THE OBVIOUS CHANGES TO THE LINK http://www.geocities.com/SiliconValley/Monitor/4710/

A couple lamp sockets wired in parallel and that in series with the primary should be enough of a current limit, once you select the right wattage bulbs to put in them. I think a 40 watt and a 75 watt would give 3 useful combinations. And you get a nice visual indication that a connection is made. ;-)

John Popelish

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