<html><body><div style="font-family: arial, helvetica, sans-serif; font-size: 12pt; color: #000000"><div>Thank you Pablo and team,<br></div><div><br data-mce-bogus="1"></div><div>This broadly matches the results of our investigation last week.<br data-mce-bogus="1"></div><div><br data-mce-bogus="1"></div><div>Please refer to the following log entry and the report attached to it.<br data-mce-bogus="1"></div><div><br data-mce-bogus="1"></div><div><a href="https://logbooks.jlab.org/entry/3537328" data-mce-href="https://logbooks.jlab.org/entry/3537328">https://logbooks.jlab.org/entry/3537328</a><br data-mce-bogus="1"></div><div><br data-mce-bogus="1"></div><div>Regards<br data-mce-bogus="1"></div><div><br data-mce-bogus="1"></div><div>Ruben<br data-mce-bogus="1"></div><div><br data-mce-bogus="1"></div><div><br data-mce-bogus="1"></div><div><br></div><hr id="zwchr" data-marker="__DIVIDER__"><div data-marker="__HEADERS__"><b>From: </b>"Pablo Campero Rojas" <campero@jlab.org><br><b>To: </b>"dsg-hallb magnets" <dsg-hallb_magnets@jlab.org><br><b>Sent: </b>Thursday, March 1, 2018 4:59:31 PM<br><b>Subject: </b>[Dsg-hallb_magnets] Solenoid fast dump summary<br></div><br><div data-marker="__QUOTED_TEXT__"><div style="font-family: georgia,serif; font-size: 12pt; color: #000000"><div><p style="margin: 0px; line-height: normal;"><span style="font-size: 12.0pt; font-family: 'Georgia','serif'; color: black;">Hello All,</span></p><p style="margin: 0px; line-height: normal;"><span style="font-size: 12.0pt; font-family: 'Georgia','serif'; color: black;"> </span></p><p style="margin: 0px; line-height: normal;"><span style="font-size: 12.0pt; font-family: 'Georgia','serif'; color: black;">DSG has been analyzing the Solenoid fast dump events based on the logbook entries, data archived and analyzer tools. We generated a spreadsheet (See attached) that shows all Solenoid fast dump events summary from Sep 12th, 2017 to Feb 28th, 2018. </span></p><p style="margin: 0px; line-height: normal;"><span style="font-size: 12.0pt; font-family: 'Georgia','serif'; color: black;"> </span></p><p style="margin: 0px; line-height: normal;"><span style="font-size: 12.0pt; font-family: 'Georgia','serif'; color: black;">Results indicates that there was a total of 12 fast dump during the mentioned period, from which, 11 were attributed to the QDs (Quench Detectors units used as a hardware interlock for the Voltage taps) and 1 due to the cryogenics interlock.</span></p><p style="margin: 0px; line-height: normal;"><span style="font-size: 12.0pt; font-family: 'Georgia','serif'; color: black;"> </span></p><p style="margin: 0px; line-height: normal;"><span style="font-size: 12.0pt; font-family: 'Georgia','serif'; color: black;">During the commissioning period five fast dumps occurred due to the QD1/QD2, and one due cryogenics trips (Vapor cooled lead temp > 13.5 [K]). Over the engineering run five fast dumps generated as a result of QD1 and QD2 trips; finally over the physics run period we had one fast dump also due to QD1/QD2.</span></p><p style="margin: 0px; line-height: normal;"><span style="font-size: 12.0pt; font-family: 'Georgia','serif'; color: black;"> </span></p><p style="margin: 0px; line-height: normal;"><span style="font-size: 12.0pt; font-family: 'Georgia','serif'; color: black;">Overall, we know that the main cause for the fast dumps were due to QD1 and QD2 which are covering the voltage taps in the coils (1-5) and splices, and the information/data reveals that VT18 (Voltage across splice - SJ9), which was originally part of the QD1 (Ch3 and Ch4) and QD2:Ch4 was the most conflicted voltage tap generating a total of 6 trips (See histogram attached). This evidence led to remove VT18 and VT17 from QD1:Ch4. Also voltage thresholds and time delay thresholds were increased in the QDs in order to prevent undesired fast dump events after the commissioning period (Sep, 2017). </span></p><p style="margin: 0px; line-height: normal;"><span style="font-size: 12.0pt; font-family: 'Georgia','serif'; color: black;"> </span></p><p style="margin: 0px; line-height: normal;"><span style="font-size: 12.0pt; font-family: 'Georgia','serif'; color: black;">We noticed on three occasions: for 7th, 8th and 12th fast dumps, that even when the spike voltages generated on QD1:Ch3 and QD2:Ch4; especially the Sum values of VT's combinations where VT18 was involved, were under the set thresholds and still generated a fast dumps in the Solenoid. </span></p><p style="margin: 0px; line-height: normal;"><span style="font-size: 12.0pt; font-family: 'Georgia','serif'; color: black;"> </span></p><p style="margin: 0px; line-height: normal;"><span style="font-size: 12.0pt; font-family: 'Georgia','serif'; color: black;"> </span></p><p style="margin: 0px; line-height: normal;"><span style="font-size: 12.0pt; font-family: 'Georgia','serif'; color: black;">Best Regards,</span></p><p style="margin: 0px; line-height: normal;"><span style="font-size: 12.0pt; font-family: 'Georgia','serif'; color: black;">Pablo</span></p></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></div></div></body></html>