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[AMPS] transformer oil

To: <amps@contesting.com>
Subject: [AMPS] transformer oil
From: Mike" <W4EF@dellroy.com (Mike)
Date: Sun, 30 Sep 2001 18:32:06 -0700
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Ken,=20

You can buy transformer oil from Ameritron or MFJ for $24.95/Gallon. =
Transformer=20
oil has better thermal properties than mineral oil and thus will give =
better power=20
handling than with mineral oil (MFJ gives derating curves for their =
dummy load=20
using both transformer oil and mineral oil). Per the MFJ-250 manual, =
motor oil is=20
not recommended for use in dummy loads due to its low vaporization =
temperature.

By the way, if you find a lower priced source for transformer oil, let =
me know,=20
I need a couple more gallons for an upcoming project=20

73 de Mike, W4EF.......... =20

P.S. Since your dummy load is of unknown origin, you may want to =
properly dispose of=20
the old oil as it might contain PCB's which are known to be carcinogenic =
when burned. =20
  ----- Original Message -----=20
  From: Ken Barber=20
  To: Radio-contesting.com=20
  Sent: Sunday, September 30, 2001 5:03 PM
  Subject: [AMPS] transformer oil


  Hi,
    I purchased an old military 1000 watt dummy load at a hamfest today. =
 It is quite large and has industrial size radiators.  I ran 500 watts =
into it for about 5 minutes.  I noticed that the input area where the =
"N" connector is fastened got quite warm, whereas the rest of the dummy =
load didn't seem to get warm at all.  I opened it up and found that the =
oil is low and would not completely cover up the resistive element and =
that the oil is rather dirty.  I saw in a radio handbook that =
transformer oil may be obtained from the local power company, so I will =
try them as a source.  If you know of another source, please let me know =
who it is.
    I know nothing about oil and heat transfer, so could someone explain =
why one could not use motor oil or mineral oil or cooking oil such as =
olive oil ?  Secondly, should the transformer oil be filled right up to =
the top of the dummy load or should there be a little room for =
expansion?
  73,
  Ken W2DTC
  =20

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<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.0 Transitional//EN">
<HTML><HEAD>
<META content=3D"text/html; charset=3Diso-8859-1" =
http-equiv=3DContent-Type>
<META content=3D"MSHTML 5.00.3018.900" name=3DGENERATOR>
<STYLE></STYLE>
</HEAD>
<BODY bgColor=3D#ffffff>
<DIV><FONT face=3D"Courier New" size=3D2>Ken, </FONT></DIV>
<DIV>&nbsp;</DIV>
<DIV><FONT face=3D"Courier New" size=3D2>You can buy&nbsp;transformer =
oil from=20
Ameritron or MFJ for $24.95/Gallon. T</FONT><FONT face=3D"Courier New"=20
size=3D2>ransformer </FONT></DIV>
<DIV><FONT face=3D"Courier New" size=3D2>oil has better thermal =
properties than=20
mineral oil and thus will give better power&nbsp;</FONT></DIV>
<DIV><FONT face=3D"Courier New" size=3D2>handling than with mineral oil =
(MFJ gives=20
derating curves for their dummy load </FONT></DIV>
<DIV><FONT face=3D"Courier New" size=3D2>using both transformer =
</FONT><FONT=20
face=3D"Courier New" size=3D2>oil and mineral oil). Per the MFJ-250 =
manual, motor=20
oil is </FONT></DIV>
<DIV><FONT face=3D"Courier New" size=3D2>not recommended for use in =
</FONT><FONT=20
face=3D"Courier New" size=3D2>dummy loads due to its low vaporization=20
temperature.</FONT></DIV>
<DIV>&nbsp;</DIV>
<DIV><FONT face=3D"Courier New" size=3D2>By the way, if you find a lower =
priced=20
source for&nbsp;transformer&nbsp;oil, let me know, </FONT></DIV>
<DIV><FONT face=3D"Courier New" size=3D2>I need a couple more gallons =
for an=20
upcoming project</FONT>&nbsp;</DIV>
<DIV><FONT face=3D"Courier New" size=3D2></FONT>&nbsp;</DIV>
<DIV><FONT face=3D"Courier New" size=3D2>73 de Mike, =
W4EF..........&nbsp;=20
</FONT></DIV>
<DIV>&nbsp;</DIV>
<DIV><FONT face=3D"Courier New" size=3D2>P.S. Since your dummy load is =
of unknown=20
origin, you may want to properly dispose of </FONT></DIV>
<DIV><FONT face=3D"Courier New" size=3D2>the old </FONT><FONT =
face=3D"Courier New"=20
size=3D2>oil as it might contain PCB's which are known to be =
carcinogenic when=20
burned.&nbsp; </FONT></DIV>
<BLOCKQUOTE=20
style=3D"BORDER-LEFT: #000000 2px solid; MARGIN-LEFT: 5px; MARGIN-RIGHT: =
0px; PADDING-LEFT: 5px; PADDING-RIGHT: 0px">
  <DIV style=3D"FONT: 10pt arial">----- Original Message ----- </DIV>
  <DIV=20
  style=3D"BACKGROUND: #e4e4e4; FONT: 10pt arial; font-color: =
black"><B>From:</B>=20
  <A href=3D"mailto:kenw2dtc@home.com"; title=3Dkenw2dtc@home.com>Ken =
Barber</A>=20
  </DIV>
  <DIV style=3D"FONT: 10pt arial"><B>To:</B> <A =
href=3D"mailto:amps@contesting.com"=20
  title=3Damps@contesting.com>Radio-contesting.com</A> </DIV>
  <DIV style=3D"FONT: 10pt arial"><B>Sent:</B> Sunday, September 30, =
2001 5:03=20
  PM</DIV>
  <DIV style=3D"FONT: 10pt arial"><B>Subject:</B> [AMPS] transformer =
oil</DIV>
  <DIV><BR></DIV>
  <DIV><STRONG><FONT face=3D"Comic Sans MS" =
size=3D4>Hi,</FONT></STRONG></DIV>
  <DIV><STRONG><FONT face=3D"Comic Sans MS" size=3D4>&nbsp; I purchased =
an=20
  old&nbsp;military&nbsp;1000 watt dummy load at a hamfest today.&nbsp; =
It is=20
  quite large and has industrial&nbsp;size radiators.&nbsp; I ran 500 =
watts into=20
  it for about 5 minutes.&nbsp; I noticed that the&nbsp;input area where =
the "N"=20
  connector is fastened got quite warm, whereas the rest of the dummy =
load=20
  didn't seem to get warm at =
all.&nbsp;&nbsp;</FONT></STRONG><STRONG><FONT=20
  face=3D"Comic Sans MS" size=3D4>I opened it up and found that the oil =
is low and=20
  would not completely cover up the resistive element and that the=20
  oil&nbsp;is&nbsp;rather =
dirty.&nbsp;&nbsp;</FONT></STRONG><STRONG><FONT=20
  face=3D"Comic Sans MS" size=3D4>I saw in a radio handbook =
that&nbsp;transformer=20
  oil may be obtained from the local power&nbsp;company, so I will try =
them as a=20
  source.&nbsp; If you know of another source, please let me know who it =

  is.</FONT></STRONG></DIV>
  <DIV><STRONG><FONT face=3D"Comic Sans MS" size=3D4>&nbsp; I know =
nothing about oil=20
  and heat transfer, so could someone explain why one could not use =
motor oil or=20
  mineral oil or cooking oil such as olive oil ?&nbsp;&nbsp;Secondly, =
should the=20
  transformer oil be filled right up to the top of the dummy =
load&nbsp;or should=20
  there be a little room for expansion?</FONT></STRONG></DIV>
  <DIV><STRONG><FONT face=3D"Comic Sans MS" =
size=3D4>73,</FONT></STRONG></DIV>
  <DIV><STRONG><FONT face=3D"Comic Sans MS" size=3D4>Ken =
W2DTC</FONT></STRONG></DIV>
  <DIV><STRONG><FONT face=3D"Comic Sans MS"=20
size=3D4></FONT></STRONG>&nbsp;</DIV></BLOCKQUOTE></BODY></HTML>

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