sPHENIX discussion of the superconducting solenoid

[Kin Yip <kinyip AT bnl.gov>]

-------- Forwarded Message -------- Subject: Arc Flash in sPHENIX magnet. Date: Thu, 30 Jul 2015 15:48:46 -0400 From: Sandberg, Jon N <jsandberg AT bnl.gov> To: Yip, Kin <kinyip AT bnl.gov>, Tuozzolo, Joseph E <tuozzolo AT bnl.gov>, Than, Yatming (Roberto) <ythan AT bnl.gov>, Lambiase, Robert <lambiase AT bnl.gov>

Greetings:

 

This calculation presumes  that a conductor in the magnet opens.  In this case the question of how much power can be delivered to the helium is a question of the voltage across the arc and the current in the arc.  A search of some literature on the voltage across an arc in gas has lead me to believe that the voltage drop across a 10 mm gap would be no larger than 66 volts for 4600 amperes through it.  This would mean 303 kW could be deposited into the helium.  If the magnet coils went normal when this event occurred the power dissipated in the now resistive superconductor would also be transferred to the helium.  I did not account for this.  I would appreciate others looking at this analysis and commenting on how reasonable it is………………….Thanks, Jon

 

Jon Sandberg

Chief Electrical Engineer

Collider-Accelerator Department

Brookhaven National Laboratory

Building 911B

Upton, NY, 11973

631.344.4682

Jsandberg AT bnl.gov

 

Attachment: sPHENIX Arc Flash.ppt
Description: MS-Powerpoint presentation