Maker Pro
Maker Pro

Need foam cutter power supply circuit advice

B

BrianS

I need some expert advice on a power supply circuit. Normally I would
have asked my friend who was an electronic wiz, but he's just passed
away
this year so I need a new electronic expert. I know this is probably a
lot to ask, but I figured there might be some kind soul who might lend
a little of their time. I would gladly exchange what knowledge I have
on other subjects such as AutoCAD, Linux, programming, etc.

I want to make a power supply circuit for a foam cutter. I've been
researching them on the Internet and found a number of different plans,
but I don't know enough about electronics to judge which one would be
best and if any of them could be modified (safely) to fit some of the
parts I already have. My skills are limited to soldering and following
a good set of instructions, not design.

I've found these different designs:
http://members.fortunecity.co.uk/slmohr/rcinterest2A.htm
http://www.uoguelph.ca/~antoon/gadgets/hotwire/hotwire.html
http://nsrca.org/technical/tip_tricks/foam_cutter/foam_cutting_power_supply.htm
From the sites I've read many recommend that you do not use nichrome
wire. So I have some stainless steel wire (0.020in DIA) left over
from a different project. I have no idea what ohms/foot rating it has.
Also I have a working transformer that is 120V input and 12V 8amp
output.
Most of these designs call for 24V transformers.

My questions are:
1. Which design do you think would give the best control of the wire
temperature?
2. Can any of these designs work with the wire and transformer that I
already have?
If so, what changes to the components (if any) would be required?

Also this is the third time I tried posting this message (over the past
two
days) to google groups so if there are two other copies that I can't
see for some
reason I am sorry.

Thanks in advance
Brian
 
J

Jon

Brian,
A "quick and dirty" method is to connect the output of a variac to a
step-down transformer. Use the variac to control the temperature.
Inexpensive Variacs are readily available on the surplus market. From
a safety standpoint, it's not a good idea to use the Variac output
directly, since variacs are variable autotransformers and do not
provide isolation from the mains.
..
I have successfully used nichrome wire for this application.
Regards,
Jon
 
Top