<html><head><meta http-equiv="content-type" content="text/html; charset=utf-8"></head><body dir="auto"><div></div><div>Good afternoon</div><div><br></div><div>The DC Power Group assisted us today to carry out some tests on the malfunctioning Torus power supply.</div><div><br></div><div>The good news is that the output transistor banks all appear to be working as expected - i.e. they do not appear to have been damaged during the ramp to 100 A yesterday. The ‘burning smell’ reported yesterday could possibly be explained by the soft-start resistors not being automatically disengaged once the main breaker was closed. They then continued to carry current and overheated. They did behave well today though. Nonetheless these resistors and their control circuit will require further investigation.</div><div><br></div><div>The bad news is that the power supply is still limiting ramp-up rates to no higher than 0.5 A/s. Obviously we need to understand what is causing this as this might indicate other more serious issues with the supply.</div><div><br></div><div>The DC Power Group will be reviewing the test data gathered today and we will continue our tests tomorrow - most likely in the afternoon tomorrow.</div><div><br></div><div>Nick will be posting a Hall B log entry later today with all the captured voltage and current curves.</div><div><br></div><div>Regards</div><div><br></div><div>Ruben</div><div><br>On Dec 2, 2017, at 8:38 AM, Raffaella De Vita <<a href="mailto:Raffaella.Devita@ge.infn.it">Raffaella.Devita@ge.infn.it</a>> wrote:<br><br></div><blockquote type="cite"><div><span>Dear All,</span><br><span>according to this morning update from MCC, machine restoration is taking longer than planned. Hall B is now scheduled to receive beam on Monday. The Hall will remain in restricted access until further notice.</span><br><span>Best regards,</span><br><span> Raffaella</span><br><span>_______________________________________________</span><br><span>Hallb-engineering mailing list</span><br><span><a href="mailto:Hallb-engineering@jlab.org">Hallb-engineering@jlab.org</a></span><br><span><a href="https://mailman.jlab.org/mailman/listinfo/hallb-engineering">https://mailman.jlab.org/mailman/listinfo/hallb-engineering</a></span><br></div></blockquote></body></html>