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<DIV><FONT face=Arial size=2>One thing I used to use back in the days was a toy
train transformer. The kind that had a variable speed slide. Worked
quite well as you could adjust it for any thickness of wire. We used piano
wire too and it worked well also. </FONT></DIV>
<DIV><FONT face=Arial size=2></FONT> </DIV>
<DIV><FONT face=Arial size=2></FONT> </DIV>
<DIV>Wayne Galligan<BR><BR></DIV>
<BLOCKQUOTE
style="PADDING-RIGHT: 0px; PADDING-LEFT: 5px; MARGIN-LEFT: 5px; BORDER-LEFT: #000000 2px solid; MARGIN-RIGHT: 0px">
<DIV style="FONT: 10pt arial">----- Original Message ----- </DIV>
<DIV
style="BACKGROUND: #e4e4e4; FONT: 10pt arial; font-color: black"><B>From:</B>
<A title=ed_alt@hotmail.com href="mailto:ed_alt@hotmail.com">Ed Alt</A> </DIV>
<DIV style="FONT: 10pt arial"><B>To:</B> <A
title=nsrca-discussion@lists.nsrca.org
href="mailto:nsrca-discussion@lists.nsrca.org">General pattern discussion</A>
</DIV>
<DIV style="FONT: 10pt arial"><B>Sent:</B> Thursday, May 21, 2009 10:58
PM</DIV>
<DIV style="FONT: 10pt arial"><B>Subject:</B> Re: [NSRCA-discussion] Foam
cutter power supply</DIV>
<DIV><BR></DIV>
<DIV><FONT face=Arial size=2>Matt:</FONT></DIV>
<DIV><FONT face=Arial size=2>That might work, although I don't know if you
would be getting much out of the light bulb at the current levels that would
heat a nichrome wire. It might be easier to just start with one turned
up about half way (the fine tune dimmer) and the course
control turned all the way down, then gradually turn up the course
control dimmer until the wire is hot enough to melt some foam. Mark that
setting, then try the fine adjust to see if it gives the needed span of
control. If not, bump the course control up a little and repeat the
initial calibration. Never tried it myself, but that ought to
work. Another way is to get a step down transformer and place that on
the output of just one dimmer control. The secondary winding is then at
a lower and safer voltage and you can do the fine tuning with just one
control. I have a setup that works this way that I have used for small stuff,
but it could be done with larger setups too.</FONT></DIV>
<DIV><FONT face=Arial size=2></FONT> </DIV>
<DIV><FONT face=Arial size=2>Ed</FONT></DIV>
<DIV><FONT face=Arial size=2></FONT> </DIV>
<DIV><FONT face=Arial size=2></FONT> </DIV>
<DIV><FONT face=Arial size=2></FONT> </DIV>
<DIV>----- Original Message ----- </DIV>
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style="PADDING-RIGHT: 0px; PADDING-LEFT: 5px; MARGIN-LEFT: 5px; BORDER-LEFT: #000000 2px solid; MARGIN-RIGHT: 0px">
<DIV
style="BACKGROUND: #e4e4e4; FONT: 10pt arial; font-color: black"><B>From:</B>
<A title=rcmaster199@aol.com
href="mailto:rcmaster199@aol.com">rcmaster199@aol.com</A> </DIV>
<DIV style="FONT: 10pt arial"><B>To:</B> <A
title=nsrca-discussion@lists.nsrca.org
href="mailto:nsrca-discussion@lists.nsrca.org">nsrca-discussion@lists.nsrca.org</A>
</DIV>
<DIV style="FONT: 10pt arial"><B>Sent:</B> Thursday, May 21, 2009 11:22
PM</DIV>
<DIV style="FONT: 10pt arial"><B>Subject:</B> Re: [NSRCA-discussion] Foam
cutter power supply</DIV>
<DIV><BR></DIV>Hmmm.<BR><BR>It may work really well if the light (low watts)
was in series with the NiCr wire. He might get a visual cue as to where to
turn the dimmer<BR><BR>What do you think Eddie?<BR><BR>Matt<BR>
<DIV><BR></DIV>
<DIV><BR></DIV>
<DIV><BR></DIV>-----Original Message-----<BR>From: Ed Alt <<A
href="mailto:ed_alt@hotmail.com">ed_alt@hotmail.com</A>><BR>To: General
pattern discussion <<A
href="mailto:nsrca-discussion@lists.nsrca.org">nsrca-discussion@lists.nsrca.org</A>><BR>Sent:
Thu, 21 May 2009 5:40 am<BR>Subject: Re: [NSRCA-discussion] Foam cutter
power supply<BR><BR>
<DIV id=AOLMsgPart_3_415f6040-1a37-4132-9287-2d74e5a30e12>
<DIV><FONT face=Arial size=2>Paul:<BR>The way a light dimmer works is to
chop a variable percentage of the AC voltage waveform off, so the brighter
the light is, the more full and complete the 60 hz sine wave is that
represents the voltage applied to the load (the bulb). As you reduce the
output, it chops off more and more of the output. It has to work this
way, otherwise the dimmer would be the size of a toaster oven to have enough
mass and surface area to dissipate the heat that would build up in it if all
it did was to drop a portion of the voltage across it. In other words,
it is either all the way off for a period of time (no power dissipated in it
at that time), or all the way on like it was a piece of copper wire (no
appreciable power disspated at that time). Anyway, what you are
apparently reading is the what the meter still "thinks" is the RMS (root
mean square) voltage of the sine wave. It probably is reducing the
meter reading somewhat, but not nearly as much as you might
expect.</FONT></DIV>
<DIV><FONT face=Arial size=2></FONT> </DIV>
<DIV><FONT face=Arial size=2></FONT> </DIV>
<DIV><FONT face=Arial size=2>The reason this works for heating the nichrome
wire at the right temperature is for the same reason the light bulb would
get dimmer. You are changing the average power delivered to the
resistive load (the nichrome wire), so even though there are still some high
voltage peaks, the average power is managed effectively. I hope this
helps.</FONT></DIV>
<DIV><FONT face=Arial size=2></FONT> </DIV>
<DIV><FONT face=Arial size=2>Ed</FONT></DIV>
<BLOCKQUOTE
style="PADDING-RIGHT: 0px; PADDING-LEFT: 5px; MARGIN-LEFT: 5px; BORDER-LEFT: rgb(0,0,0) 2px solid; MARGIN-RIGHT: 0px">
<DIV
style="FONT: 10pt arial; font-size-adjust: none; font-stretch: normal; -x-system-font: none">-----
Original Message ----- </DIV>
<DIV
style="BACKGROUND: rgb(228,228,228); FONT: 10pt arial; font-size-adjust: none; font-stretch: normal; -x-system-font: none; -moz-background-clip: -moz-initial; -moz-background-origin: -moz-initial; -moz-background-inline-policy: -moz-initial"><B>From:</B>
<A title=plachance@cox.net href="mailto:plachance@cox.net">Paul
LaChance</A> </DIV>
<DIV
style="FONT: 10pt arial; font-size-adjust: none; font-stretch: normal; -x-system-font: none"><B>To:</B>
<A title=nsrca-discussion@lists.nsrca.org
href="mailto:nsrca-discussion@lists.nsrca.org">NSRCA Mailing List</A>
</DIV>
<DIV
style="FONT: 10pt arial; font-size-adjust: none; font-stretch: normal; -x-system-font: none"><B>Sent:</B>
Thursday, May 21, 2009 4:25 AM</DIV>
<DIV
style="FONT: 10pt arial; font-size-adjust: none; font-stretch: normal; -x-system-font: none"><B>Subject:</B>
[NSRCA-discussion] Foam cutter power supply</DIV>
<DIV><BR></DIV>
<DIV><FONT face=Arial size=2>Hi all,</FONT></DIV>
<DIV><FONT face=Arial size=2></FONT> </DIV>
<DIV><FONT face=Arial size=2>I was told about a way to make a power supply
for a foam cutter using 2 dimmer switches. I was also told to
measure the final voltage to get an approximate starting point of 15
volts. I am not getting a voltage change with the dimmers. I
have tested to see that there is a difference by using a drill to see that
it is reducing the speed. Does anyone know how I can measure to get
a starting point or is it going to be trial and error? </FONT></DIV>
<DIV><FONT face=Arial size=2></FONT> </DIV>
<DIV><FONT face=Arial size=2>Thanks in advance,</FONT></DIV>
<DIV><FONT face=Arial size=2></FONT> </DIV>
<DIV><FONT face=Arial size=2>Paul</FONT></DIV>
<DIV></DIV>
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