LN Cooling Page

  1. Vibration Mitigation
    1. For information about OVMS data see IT 7005
    2. Hiberbation How To Doc (26-oct-2018)
  2. For cooling outages and other situations requiring power off: Power Off Instructions
> On 2018-08-09 17:11, James Riedl wrote:
> > Hello LN team, We've been hearing an audible alarm in the chamber that
> > sounds like a "whooping" sound - perhaps like a naval vessel alarm.
> > It appears to be related to the lack of ICS cooling.  Is this a LN
> > alarm?   Nobody on the summit recognizes the alarm.  Thanks, James

From: Thomas Bertram <bertram@mpia.de>
Subject: Re: Mystery alarm near visitor's gallery

Dear all,

Indeed, the alarm that you heard was caused by the lack of glycol flow, as James and Florian mentioned. The
glycol water flow stopped on August 7th at around 2pm. It was reestablished yesterday at around noon (MST).

The alarm goes off for about 10 seconds when the glycol flow stops. Each cabinet acts on its behalf, so if there
is a glycol flow outage on both sides of the telescope, all six electronics cabinets complain in parallel for
about 10 seconds. Then each cabinet silently gets warmer until it reaches a threshold temperature where the
power is completely switched off. At that point it cools down again. Once below the threshold temperature, the
power is switched back on and the cabinet complains for about 10 seconds, if it still doesn't get sufficient
glycol flow, and warms up. The cycle differs a bit from cabinet to cabinet, so you have up to six cabinets each
complaining every 2h-5h for about 10 seconds until the glycol flow is back. This behavior cannot (and should
not) be switched off remotely.

If LBTO has to deactivate the cooling system for a longer period, we would ask you to switch off LN. But it seems
as if the cooling system is working again, so I assume that there is no need to act on the alarms anymore.

  1. Pictures and email from feb.2015 exchange:
    1. P1010194.JPG
    2. mpiaCooler11feb2015.pdf
    3. stirlingEmail11feb2015.pdf
    4. wlRrBottlePrchs18mar2015.pdf
-- %USERSIG{AlbertConrad - 2014-11-20}%

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Topic revision: r6 - 26 Oct 2018, AlbertConrad
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