<p>That is how all of the manufacturers do it. Next time you plug a pack in, spin the motor by hand as the arming tones sound. You will notice that most motors will change pitch and volume as it passes through the arcs of different phases.</p>
<p>On smaller outrunners, you can actually see the prop twitch when the motor beeps. And depending on the quality of magnets, inductance of the motor, etc, different motors will sound at different volumes.</p>
<div class="gmail_quote">On Oct 9, 2011 2:20 PM, "Lightfoot" <<a href="mailto:lightfoot@sc.rr.com">lightfoot@sc.rr.com</a>> wrote:<br type="attribution"><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">
<div lang="EN-US" link="blue" vlink="purple"><div><p class="MsoNormal"><span style="font-size:11.0pt;color:#1F497D">You may be right. Time for some experiments.<u></u><u></u></span></p><p><u></u><span style="font-size:11.0pt;color:#1F497D"><span>1)<span style="font:7.0pt "Times New Roman""> </span></span></span><u></u><span style="font-size:11.0pt;color:#1F497D">Different size motors – same ESC<u></u><u></u></span></p>
<p><u></u><span style="font-size:11.0pt;color:#1F497D"><span>2)<span style="font:7.0pt "Times New Roman""> </span></span></span><u></u><span style="font-size:11.0pt;color:#1F497D">No motor at all<u></u><u></u></span></p>
<p><u></u><span style="font-size:11.0pt;color:#1F497D"><span>3)<span style="font:7.0pt "Times New Roman""> </span></span></span><u></u><span style="font-size:11.0pt;color:#1F497D">Same motor – different ESCs<u></u><u></u></span></p>
<p><u></u><span style="font-size:11.0pt;color:#1F497D"><span>4)<span style="font:7.0pt "Times New Roman""> </span></span></span><u></u><span style="font-size:11.0pt;color:#1F497D">And most likely to succeed - write the mfgs.<u></u><u></u></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;color:#1F497D"><u></u> <u></u></span></p><p class="MsoNormal"><b><i><span style="font-size:13.5pt;font-family:"Brush Script MT";color:#1F497D">Jay Marshall</span></i></b><span style="color:#1F497D"> </span><span style="font-size:11.0pt;color:#1F497D"><u></u><u></u></span></p>
<div style="border:none;border-top:solid #B5C4DF 1.0pt;padding:3.0pt 0in 0in 0in"><p class="MsoNormal" style="margin-left:.5in"><b><span style="font-size:10.0pt">From:</span></b><span style="font-size:10.0pt"> <a href="mailto:nsrca-discussion-bounces@lists.nsrca.org" target="_blank">nsrca-discussion-bounces@lists.nsrca.org</a> [mailto:<a href="mailto:nsrca-discussion-bounces@lists.nsrca.org" target="_blank">nsrca-discussion-bounces@lists.nsrca.org</a>] <b>On Behalf Of </b>Scott Pavlock<br>
<b>Sent:</b> Sunday, October 09, 2011 2:03 PM<br><b>To:</b> General pattern discussion<br><b>Subject:</b> Re: [NSRCA-discussion] beep tones<u></u><u></u></span></p></div><p class="MsoNormal" style="margin-left:.5in"><u></u> <u></u></p>
<p style="margin-left:.5in">Yes it is in fact pulsing current through the motor. An electric motor is very similar to a speaker, and vibrating the windings at specific frequencies will create different musical tones.<u></u><u></u></p>
<div><p class="MsoNormal" style="margin-left:.5in">On Oct 9, 2011 1:04 PM, "George Kennie" <<a href="mailto:geobet4evr@gmail.com" target="_blank">geobet4evr@gmail.com</a>> wrote:<u></u><u></u></p><div><p class="MsoNormal" style="margin-left:.5in">
I have a question that came up at ther flying field yesterday.<u></u><u></u></p></div><div><p class="MsoNormal" style="margin-left:.5in">The query was: What produces the arming tone and the cell count tones that are <u></u><u></u></p>
</div><div><p class="MsoNormal" style="margin-left:.5in">audible when the battery is plugged in to an electric motor powered model?<u></u><u></u></p></div><div><p class="MsoNormal" style="margin-left:.5in"> <u></u><u></u></p>
</div><div><p class="MsoNormal" style="margin-left:.5in">There were guys that were adament that the tones were produced by the current<u></u><u></u></p></div><div><p class="MsoNormal" style="margin-left:.5in">surging through the motor.<u></u><u></u></p>
</div><div><p class="MsoNormal" style="margin-left:.5in"> <u></u><u></u></p></div><div><p class="MsoNormal" style="margin-left:.5in">There was confusion due to the fact that no visible speaker could be observed.<u></u><u></u></p>
</div><div><p class="MsoNormal" style="margin-left:.5in"> <u></u><u></u></p></div><div><p class="MsoNormal" style="margin-left:.5in">I felt that there had to be nano oscillator circuits in the esc working some kind of a<u></u><u></u></p>
</div><div><p class="MsoNormal" style="margin-left:.5in">nano piezo circuit generating the required tones, but I really had no idea.<u></u><u></u></p></div><div><p class="MsoNormal" style="margin-left:.5in"> <u></u><u></u></p>
</div><div><p class="MsoNormal" style="margin-left:.5in">Can somebody please clear up the confusion, ? anybody,? Peter???<u></u><u></u></p></div><div><p class="MsoNormal" style="margin-left:.5in"> <u></u><u></u></p></div>
<div><p class="MsoNormal" style="margin-left:.5in">Thanks <u></u><u></u></p></div><div><p class="MsoNormal" style="margin-left:.5in"> <u></u><u></u></p></div><div><p class="MsoNormal" style="margin-left:.5in">Georgie <u></u><u></u></p>
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