[Beowulf] Re: Emergency Power Off

[Robert G. Brown]

On Mon, 19 Mar 2007, Jim Lux wrote:

> At 03:19 PM 3/19/2007, Robert G. Brown wrote:
>> On Mon, 19 Mar 2007, David Mathog wrote:
>> 
>>> After looking at the specs I believe that at least 4 of the 5
>>> can be wired to shut down instantly.  (Not sure about the one
>>> desktop size APC unit in the room, as it isn't mine so I don't
>>> have the manual). However it seems that turning off the
>>> tripp-lite UPS requires a positive voltage (12V) on the
>>> inverter shutdown line.  Which means, that even after the
>>> power has been killed (overtemp, red kill button,
>>> or building power shut down) the fireman entering this room would
>>> still need to smack another (not yet extant) red kill button, and
>>> that button is going to need DC power in order to work.

OK, this and David's replies are well worth preserving in marble and
bronze somewhere.  I will dutifully spec out and assemble one as per the
instructions below, and let my electrician friend do that last itty bit
of wiring it in (or at least, wiring in the 120 line to drive the power
supply).

So, if the same kill switch controls the supply breakers, is this
accomplished by just replacing the box breakers with special ones that
can be tripped by the control lines?  Sort of like a GFCI breaker with
an extra wire where you can feed in a deliberate imbalance high enough
to trip it?

So with the resources you included I'll even try to answer this
myself...

     rgb

-- 
Robert G. Brown	                       http://www.phy.duke.edu/~rgb/
Duke University Dept. of Physics, Box 90305
Durham, N.C. 27708-0305
Phone: 1-919-660-2567  Fax: 919-660-2525     email:rgb at phy.duke.edu