[Dsg-dc] DC gas safety system

[Brian Eng]

While I haven't looked at it in depth, off-hand I don't think we need to change the design; if it worked for CLAS6 that should be enough validation that the system is sound.

What does need to be changed is the implementation: not having any wiring outside of the chassis itself, replacing grommets with connectors, adding serviceable fusing, and small things like switching from lamps to LEDs, etc.

We'll start putting together a parts list for the new system.

> On May 23, 2017, at 7:09 PM, Amrit Yegneswaran <yeg at jlab.org> wrote:
> 
> marc,
> with regards to §2, highlighted, after much deliberation, i am of the opinion that because of the exigent circumstances, cosmic tests and noise source debugging, replacing the underrated cable with a cable of adequate rating, was the right thing to do. however, i am concerned about the compliance of this old system with current safety requirements. one definitely does not want to encounter hitherto unknown problems. so, notwithstanding the circumstances, the system needs to be replaced as soon as possible. 
> 
> as we discussed at the meeting today, dsg could build a safety system to replace the existing system; hall b technicians could run the new cables (if needed).
> 
> brian, please discuss the matter with george and come up with a design; mindy will fabricate the needed parts, which marc and george can install.  brian, george, and marc please provide a cost estimate for the new system. 
> 
> amrit
> 
> From: "Marc Mcmullen" <mcmullen at jlab.org>
> To: "dsg-dc" <dsg-dc at jlab.org>
> Sent: Tuesday, May 23, 2017 5:11:40 PM
> Subject: [Dsg-dc] DC gas safety system
> 
> Hi Morgan,
> 
> Brian and I have replaced the 24VAC source cables which run from the 
> SFL3 gas safety system box, to the distribution box (small one with the 
> barrier blocks). We have also removed the bad barrier block from the 
> distribution and relocated the R1/2 solenoid power wires to the single 
> barrier block.
> 
> Brian calculated the total draw of the solenoids to be just under 6amps 
> for R1/2, the new cable p/n rates it at 15A vs. 4.9A (rating for 18awg 
> cable, which was replaced).
> 
> We tested the solenoids with the safety system box in local mode. All 
> were audibly verified. We left the supply flow at 0Lpm, as you requested.
> 
> Thanks,
> 
> -- 
> Marc McMullen
> Detector Support Group
> 757-269-7738