June 11, 2013 Solenoid Meeting

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Thursday June 6,2013 at 11am At Jefferson Lab, the meeting will be held in room CC F324


C. Rode, T. Whitlatch, E. Wolin, B. Flora (via phone for short duration..sorry), E. Chudakov, J. Creel, G. Young, P. Rossi, J. Gomez, R. Ent, W. Schneider, P. Ghoshal


  1. Incorporate quench detection balance/tests into the 140A procedure (Rev C) - George Media:140A procedure.pdf
  2. Update hardware QD with dial pot and PLC with inductance algorithm - Elliot
  3. Add full resistance measurement and acceptable value to 140A procedure - George
  4. Identify all known buggers in the procedure for approval - George
  5. Clean up refrigerator and get ready for cooldown - Jonathan
  6. Determine if turn to turn short could have caused quench in coil 1A - Eugene
  7. Determine what is a safe current to run at using the existing refrigerator - all
  8. Set up a meeting with all parties to get agreement on the path forward - Tim
  9. Write up determination of what it would take to catch a quench once it starts - Probir/George media:Quench propogation.pdf
  10. Write up final analysis of quench (suppositions) - George/Eugene
  11. Write up high current portion of procedure (Rev D) - George
  12. Balance Power supply for 25H - Giles
  13. Order 2 additional burst discs - Tim
  • Do we go right into high current from 140A if ready?
  • Path Forward .......

Useful Info

  • Documents available at M:\halld_engineering\Solenoid\Commissioning\Response to Quench

Meeting Minutes

We discussed the results of last week's meeting and the proposed path forward. We went through Probir's margin comparison for different currents and temperatures as well as George's latest 140A commissioning procedure. Also discussed, was whether or not the quench could be caught. It appears that the answer is no. Once it starts, at least 1 coil will completely quench based on Probir's analysis. A discussion on the required tuning of the power supply for 25H was required for the 140A and full current testing revealed that it may not be necessary for the commissioning if the smooth ramp profile keeps the voltage spikes below 300mV. 300mV can be used for the hardwire quench detector during commissioning. The data from last week's warm ramp up will be reviewed and additional ramp tests at lower rate changes will be performed warm if necessary. Eugene did not want to make the tuning changes if we did not have to. Jonathan brought forth the suggestion to bring a signal from the refrigerator if the compressors go down or other catastrophic event happens that the magnet will immediately fast dump. This is being incorporated. The refrigerator is still being cleaned and may be ready to cool down the magnet early next week. Discussion on the allowable margin to run the magnet safely yielded the following; It should be assumed that the quench of the magnet last month should be the new zero point. The new maximum running current should yield a calculated margin of at least 0.4K above the new zero (or 0.9K above Alcorn's spec). This applies to whether or not a dewar is attached. Analysis shows that 4.5K/1350A would be acceptable. Probir will calculate what temperature is needed to run at 1500A and 1360A with this margin. Discussions on the adequacy of the existing dump resister determined that the current dump resistor is adequate and changing will not necessarily help. It was also recommended that we ramp up in steps when we near higher currents to check the temperature stability and voltage. George will add this to the full current commissioning procedure. The path forward was also discussed and it was agreed that we would not start cooldown until we have a preliminary write up outlining the results of the quench analysis (including turn to turn short), dump resistor determination and maximum current/margin rationale. This is to be accepted by Bill Schneider and Bob Flora. The 140A procedure should be approved this week (at JLAB) and a preliminary high current run procedure by next week. If all is good with the 140A testing, we would go right into the high current commissioning and mag field mapping.

New Action Items

  1. Complete 140A procedure (Rev C) - George (this is in review now with some small changes needed)
  2. Review 140A procedure and comment - all
  3. Update hardware QD with dial pot and PLC with inductance algorithm - Elliot
  4. Clean up refrigerator and get ready for cooldown - Jonathan
  5. Determine if turn to turn short could have caused quench in coil 1A - Eugene
  6. Write up quench analysis, dump resitor and max current rationale for review - George
  7. Review previous low current ramp for voltage spikes and perform additional low rate ramping if necessary - Giles
  8. Write up high current portion of procedure (Rev D) - George
  9. Balance Power supply for 25H (if necessary based on item 7)- Giles
  10. Implement fast dump wire connections from refrigerator - Jonathan/Elliot
  11. Calculate what temperature is needed to run at 1500A and 1360A with 0.9K margin.

Path Forward

  1. Complete the 140A procedure including the quench balance and turn to turn short check not completed in the 15A test (to be completed and signed off by June 14)
  2. Continue repair of refrigerator (to be completed by June 17)
  3. Write preliminary analysis of quench and rationale for dump resistor and max current (June 17)
  4. Review of preliminary write up by Bill Schneider and Bob Flora (June 19)
  5. Fill magnet with liquid (to be completed by June 23)
  6. Complete and sign off maximum current plan and quench analysis(Same OSP- New procedure or New OSP?)(to be completed by June 23)
  7. Perform 140A testing ( to be completed by June 28)
  8. Perform High current commissioning ( to be completed by July 1)
  9. Map magnet (to be completed by July 9)