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</style><article id="node-559043" class="node node-logentry article ia-n clearfix" role="article"><header class="node-header"><h1 class="node-title">
<a href="https://logbooks.jlab.org/entry/3486190" rel="bookmark">Follow-up Re: Torus MPS Faults</a>
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<p class="author-datetime">
Lognumber <a href="https://logbooks.jlab.org/entry/3486190" class="lognumber" data-lognumber="3486190">3486190</a>. Submitted by <a href="https://logbooks.jlab.org/user/okumar">okumar</a> on <time datetime="2017-09-28T13:27:21-0400" pubdate="pubdate">Thu, 09/28/2017 - 13:27</time>. </p>
<table class="field-vitals"><tr><th>Logbooks: </th><td><a href="https://logbooks.jlab.org/book/hbtorus">HBTORUS</a></td></tr><tr><th>References: </th><td><a href="https://logbooks.jlab.org/entry/3486179">3486179 - Torus MPS Faults</a></td></tr></table></div>
<div class="logentry node-content">
<p>Today @ 11:30am we figured out that the crowbar SCR got damaged during ramp down of the PS because of Safety OCP (over current protection) internal interlock. Safety OCP interlock switched off the main contactor but didn't engage the fast dump because of which the crowbar circuit became active. I theory the crowbar SCR shouldn't have gotten damaged, hence we are investigating the issue. Here are the list of things we are working on:</p>
<p>1. Mark Todd is taking the damaged SCR out the PS.<br />
2. I'm looking in the schematic and the BOM to find out the current and voltage rating of the SCR.<br />
3. We are also looking at the voltage divider circuit of the crowbar to find out the SCR firing voltage value.<br />
4. We are going to contact danfysik regarding the failure with possibility of getting the replacement part.<br />
5. Figure out why the fast dump didn't happen.</p>
<p>O.Kumar</p>
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