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["Visser, Gerard" <gvisser AT indiana.edu>]

Ok, anyway I think the best thing will be just try it w/o cooling and hope for the best. Please let  me know when we have some temperature history to look at on this. Best wishes,

     Gerard

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From: Ziyue Zhang <zzhan70 AT uic.edu>
Sent: Friday, May 12, 2023 4:19 PM
To: Visser, Gerard <gvisser AT indiana.edu>
Cc: Star-fst L <star-fst-l AT lists.bnl.gov>
Subject: Re: The Working Temperature of PPB on FST?

 

Hello Gerard,

Thank you for your insight on this. 

We were not specifically paying attention to the temperature during our testings before pulling out, before insertion, after insertion and after pole-tip closing. There were no alarms on temperature. However, the alarm system and online monitor system were offline for a relatively long time. For the time they were on, aside from no alarms, we can also see from history that the temperature was normal.

The disconnection was not recorded and til now we don't know who exactly did it.

Sincerely,

Ziyue

On Fri, May 12, 2023 at 3:53 PM Visser, Gerard <gvisser AT indiana.edu> wrote:

hi Zhiyue,

I don't know really, that will be hard to say. If there is no cooling at all I think there is a chance it can overheat to the point that something will be damaged. But compared to the alternative of having to get in an fix a leak, which is probably out of the question unless other subsystems have problems to fix, I guess you should just try it.

Fortunately the PPB was designed for IST which has 50% more power dissipation than FST, so it might work without cooling.

I think you could just mask the alarm, run a few days, and then we can look at plots of temperature to try to decide if it looks ok.

The actual hottest part (transistors of the voltage regulator) are ok to run at 100 deg C but that is not where the temperature sensor is I'm pretty sure.

Did no-one look at the temperatures when testing FST before the first pole-tip closing? Or was the cooling disconnected afterwards for some other work?

Sincerely,

       Gerard

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From: Ziyue Zhang <zzhan70 AT uic.edu>
Sent: Friday, May 12, 2023 3:22 PM
To: Visser, Gerard <gvisser AT indiana.edu>
Cc: Star-fst L <star-fst-l AT lists.bnl.gov>
Subject: The Working Temperature of PPB on FST?

 

Hello Gerard,

We are having some cooling issues with PPB on the FST. 

The temperature of the PPBs was higher than last run and triggered the alarm. Then we found that part of the supply/return loops for the cooling water (far away from the center of the pole tip) was not connected. So we connected them and indeed the temperature went back normal, but leakage was found in one out of the 3 lines. It will be hard to track down the leak, even worse to repair it, so we are thinking whether we can raise the temperature limit of PPB and how much we can raise it.

Regards,

Ziyue