Regulating voltage through a filament transformer

[rich brenz]

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"!

 

[petrus bitbyter]

"rich brenz" <eyeclinic@charterinternet.com> schreef in bericht
news:YFAZd.15233$ry.6111@fe03.lga...

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"!

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

 

[mike]

rich brenz wrote:

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"!

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
ht<removethis>tp://www.geocities.com/SiliconValley/Monitor/4710/

 

[John Popelish]

mike wrote:

rich brenz wrote:
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"!

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

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

 

[mike]

rich brenz wrote:

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"!

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
ht<removethis>tp://www.geocities.com/SiliconValley/Monitor/4710/