Need expert advice on power supply circuits

[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 and I've been
researching them on the Internet, 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 this wire
has. Also, I have a working transformer that is 120V input and
12V 8amp output that I would like to utilize. (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?

Thanks in advance
Brian

 

[Joseph2k]

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 and I've been
researching them on the Internet, 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
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 this wire
has. Also, I have a working transformer that is 120V input and
12V 8amp output that I would like to utilize. (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?

Thanks in advance
Brian

I understand your position. Most of us here get paid to do that kind of
work. I could offer you some improvements to the design (gets rid of
short / long wire problems). The transformer and stainless steel wire are
reasonable for the project. Think in terms of trading / barter.