sPHENIX discussion of the superconducting solenoid

["Toldo, Frank A" <fatoldo AT bnl.gov>]

The cover is back on the dog house.

 

Frank

 

From: sPHENIX-magnet-l <sphenix-magnet-l-bounces AT lists.bnl.gov> on behalf of Kin Yip <kinyip AT bnl.gov>
Date: Monday, October 25, 2021 at 3:08 PM
To: "sphenix-magnet-l AT lists.bnl.gov" <sphenix-magnet-l AT lists.bnl.gov>
Cc: "Galioto, Peter" <pgalioto AT bnl.gov>, "Sullivan, Daniel" <dans AT bnl.gov>
Subject: [Sphenix-magnet-l] Voltage-tap and Hipot tests on the sPHENIX Magnet succeeded after all the transportation/lifting

 

Hi,

 

After all the delays due to different reasons, Frank Toldo sent me an email this morning at 8:12 am that he already opened one door for the doghouse (extension).

Our Superconducting Magnet Div. colleagues (Peter Galioto and Dan Sullivan)  went to 1008 after 9 am or so to start setting up.  When I got to 1008 before 10:30 am, I saw Carl Schultheiss and then I found Piyush Joshi in addition to Peter and Dan.  Piyush told me that they had some problem in setting up and he was called to fix the problem.

 

Carl brought his cable and connectors for the voltage taps which are useful/crucial.   With Frank and Peter standing on the lift and doing all the connections, we measured the voltages

across the existing voltage taps (i.e., not those in the chimneys) at 1 A.   The maximum resistance across the coils is ~2.465 Ohm today, slightly less than 2.59 Ohm  measured in Nov. 2017 as we have additional portion of chimney that we don’t have today.

 

Voltage Tap VT10 that was faulty (and we couldn’t touch as it’s deep in the coil) during the High-Field test  was today behaving badly.  It’s probably partially connected and got different values at different times.   So, this is a reminder that we shouldn’t waste time on this voltage tap.

( Another problematic voltage tap  VT11 --- https://brookhavenlab.sharepoint.com/sites/sPHENIXMagnet/External/Lists/Calendar/DispForm.aspx?ID=173 ---

behaves normally today.  )

 

For the hipot test, we had an error of “Ramp-HI” showing up repeatedly today before lunch time.   After SMD folks checked manual during lunch-time, they finally realized that a factory default value of 5 micro-Amp was set somewhere deep that couldn’t be overwritten by setting 1 mA that we did before lunch --- their usual values were not memorized due to some dead battery (like BIOS of a computer without battery).

 

Anyway, after this was corrected, we did the hipot without any problem.   We ramp to 520 V in about 170 seconds.  The leakage current at 520 V was fluctuating around 0.6 micro-amp only.

I took a picture and attached the last screen for the hipot test.   This hipot test was a lot smoother/cleaner than the one we did in 2018 shortly before the High-Field test because there was condensation kept dripping down below the lead(s) due to helium flow.

 

After that, at Carl’s insistence, we also measured and saw all the resistance of ~200 ohms for the voltage taps.   Today’s data and old data that Carl took with Joe Dambra in 2019 may be found in our sharepoint :

 

2021-10-25 Voltage taps data and more.pdf

 

Anyway, I am happy that we finished the hipot test and all the electrical tests successfully today as  sPHENIX/PHENIX guys have started doing the work to mount the beampipe for the RHIC run.  ( If we couldn’t finish today, we probably have to wait for a bit … )

 

Thanks Peter, Dan and Piyush and also Frank for being the driver for the lift for the whole day.   Frank is putting back the door for the doghouse.  I need to ask the Cryo Group about flushing with nitrogen ….

 

Kin