[Hallb-engineering] [New Logentry] Follow-up Re: Ramp to 1000 Amps - Review of voltage data

[rfair at jlab.org]

Logentry Text:
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Review of the voltage data following the 'event' at 932 A (while ramping to 1000 A at 0.7 A/s) indicated the following:

VT18 (splice between VCL B and the superconducting bus within the SST - i.e. in liquid helium) developed a voltage spike (approx. 600 mV peak).
VT18 is part of the hardwired QD protection system which has voltage thresholds ranging form 80 mV to 125 mV.
It is likely that this voltage spike triggered the QD system which then initiated a fast dump.
The fast dump in turn produced eddy current heating in the magnet coils, causing Coil 3 to quench.
Coil 3 was the only coil to indicate a positive (resistive) voltage while all the other coils indicated inductive voltages.
All the helium in the magnet reservoir boiled-off.

It is possible that this splice joint moved somehow, producing this voltage spike.

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This is a plain text email for clients that cannot display HTML.  The full logentry can be found online at https://logbooks.jlab.org/entry/3484224
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