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<DIV><SPAN class=062440216-18082003><FONT face=Arial color=#0000ff
size=2>Alec,</FONT></SPAN></DIV>
<DIV><SPAN class=062440216-18082003><FONT face=Arial color=#0000ff
size=2></FONT></SPAN> </DIV>
<DIV><SPAN class=062440216-18082003><FONT face=Arial color=#0000ff size=2>There
are a couple of curves in the 2001 E-source electronic encyclopedia (probably
more recent versions as well). They show vfd & motor efficiency vs.
speed for a vfd-fan-motor system.</FONT></SPAN></DIV>
<DIV><SPAN class=062440216-18082003><FONT face=Arial color=#0000ff
size=2></FONT></SPAN> </DIV>
<DIV><SPAN class=062440216-18082003><FONT face=Arial color=#0000ff
size=2></FONT></SPAN> </DIV>
<DIV><SPAN class=062440216-18082003><FONT face=Arial color=#0000ff
size=2>Regards,</FONT></SPAN></DIV>
<DIV><SPAN class=062440216-18082003></SPAN><SPAN class=062440216-18082003><FONT
face=Arial color=#0000ff size=2></FONT></SPAN> </DIV>
<DIV><SPAN class=062440216-18082003>
<P style="MARGIN: 0px; WORD-SPACING: 0px; TEXT-INDENT: 0px; LINE-HEIGHT: 100%"
align=left><STRONG><FONT size=2>Galen Staengl, P.E.</FONT></STRONG></P>
<P style="MARGIN: 0px; WORD-SPACING: 0px; TEXT-INDENT: 0px; LINE-HEIGHT: 100%"
align=left><FONT size=2>Staengl Engineering</FONT></P>
<P style="MARGIN: 0px; WORD-SPACING: 0px; TEXT-INDENT: 0px; LINE-HEIGHT: 100%"
align=left><FONT size=2>129 Goodman St.</FONT></P>
<P style="MARGIN: 0px; WORD-SPACING: 0px; TEXT-INDENT: 0px; LINE-HEIGHT: 100%"
align=left><FONT size=2>Charlottesville, VA 22902<BR>(434)295-8105
(phone/fax)</FONT></P>
<P style="MARGIN: 0px; WORD-SPACING: 0px; TEXT-INDENT: 0px; LINE-HEIGHT: 100%"
align=left><FONT size=2>(434)242-5859 (cell)<BR></FONT></P></SPAN></DIV></DIV>
<BLOCKQUOTE dir=ltr style="MARGIN-RIGHT: 0px">
<DIV class=OutlookMessageHeader dir=ltr align=left><FONT face=Tahoma
size=2>-----Original Message-----<BR><B>From:</B> postman@gard.com
[mailto:postman@gard.com]<B>On Behalf Of </B>Alec Stevens<BR><B>Sent:</B>
Monday, August 18, 2003 11:14 AM<BR><B>To:</B>
bldg-sim@gard.com<BR><B>Subject:</B> [bldg-sim] motor efficiency vs. VFD
speed<BR><BR></FONT></DIV>
<DIV><FONT face=Arial size=2>Hello,</FONT></DIV>
<DIV><FONT face=Arial size=2></FONT> </DIV>
<DIV><FONT face=Arial size=2>Does anyone know of published research that
relates motor efficiency to percent load as well as drive
frequency?</FONT></DIV>
<DIV><FONT face=Arial size=2>We have motor curves for efficiency vs. percent
load, but these curves all assume a nominal speed that is being maintained as
load decreases. What happens to your motor efficiency when you are also
changing the drive frequency?</FONT></DIV>
<DIV><FONT face=Arial size=2></FONT> </DIV>
<DIV><FONT face=Arial size=2>Thanks for any leads.</FONT></DIV>
<DIV><FONT face=Arial size=2>Sincerely,</FONT></DIV>
<DIV> </DIV>
<DIV><FONT face=Arial size=2>Alec Stevens, PE<BR>DMI<BR>450 Lexington St,
Newton, MA 02466<BR>p: 617-527-1525 x105 f: 617-527-6606<BR>e: <A
href="mailto:astevens@dmiinc.com">astevens@dmiinc.com</A></FONT></DIV></BLOCKQUOTE><PRE>
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