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Regulating voltage through a filament transformer

R

rich brenz

Jan 1, 1970
0
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"!
 
P

petrus bitbyter

Jan 1, 1970
0
rich brenz said:
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
 
M

mike

Jan 1, 1970
0
rich said:
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

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J

John Popelish

Jan 1, 1970
0
mike said:
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. ;-)
 
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