<html><body><div style="font-family: arial,helvetica,sans-serif; font-size: 12pt; color: #000000"><div>Folks,<br></div><div>I think these spikes are an artifact of the local measurement and are not really going through the magnet. <br data-mce-bogus="1"></div><div><br data-mce-bogus="1"></div><div>As I read the graph, each division is 0.002 s. <br data-mce-bogus="1"></div><div><br data-mce-bogus="1"></div><div>The linear portion of the largest spike takes place over ~0.0004 s.<br data-mce-bogus="1"></div><div><br data-mce-bogus="1"></div><div>The current rise during that time is ~22 A.<br data-mce-bogus="1"></div><div><br data-mce-bogus="1"></div><div>That calculates to a dI/dt of 55000 A/s.<br data-mce-bogus="1"></div><div><br data-mce-bogus="1"></div><div>The voltage to drive that spike through the magnet inductor of 5.89 H is L*dI/dt.<br data-mce-bogus="1"></div><div><br data-mce-bogus="1"></div><div>I calculate 323,950 V !!!<br data-mce-bogus="1"></div><div><br data-mce-bogus="1"></div><div>I don't think that voltage is available.<br data-mce-bogus="1"></div><div><br></div><hr id="zwchr" data-marker="__DIVIDER__"><div data-marker="__HEADERS__"><blockquote style="border-left:2px solid #1010FF;margin-left:5px;padding-left:5px;color:#000;font-weight:normal;font-style:normal;text-decoration:none;font-family:Helvetica,Arial,sans-serif;font-size:12pt;"><b>From: </b>"Tyler Lemon" <tlemon@jlab.org><br><b>To: </b>"dsg-hallb magnets" <dsg-hallb_magnets@jlab.org><br><b>Sent: </b>Thursday, September 14, 2017 9:21:44 AM<br><b>Subject: </b>[Dsg-hallb_magnets] Question regarding current fastDAQ data from Solenoid fast dump on Sept 13, 2017<br></blockquote></div><div data-marker="__QUOTED_TEXT__"><blockquote style="border-left:2px solid #1010FF;margin-left:5px;padding-left:5px;color:#000;font-weight:normal;font-style:normal;text-decoration:none;font-family:Helvetica,Arial,sans-serif;font-size:12pt;"><div style="font-family: times new roman,new york,times,serif; font-size: 12pt; color: #000000"><div>Hello,<br></div><br><div>This morning, Pete Bonneau and I were looking at the fastDAQ data Brian and Pablo sent yesterday of the ~1 second where the fast dump happened in the Solenoid.<br></div><br><div>We noticed that the current jumps ~15A and then decays several times at the very start of the ramp down (plot attached).<br></div><br><div>We think that these oscillations are caused by the dump switch flipping. Is this the cause of these oscillations? If not, what is causing the current to jump like that at the start of the fast dump?<br></div><br><div>Please let us know.<br></div><br><div>Best regards,<br></div><div>Tyler<br></div></div><br>_______________________________________________<br>Dsg-hallb_magnets mailing list<br>Dsg-hallb_magnets@jlab.org<br>https://mailman.jlab.org/mailman/listinfo/dsg-hallb_magnets<br></blockquote></div><br><div data-marker="__SIG_POST__">-- <br></div><div>George</div></div></body></html>