Bruce,

As an instrument manufacturers representative first let me say that it is bad
news for any instrument to suffer bad power incuding mass specs and computers.
The problem is not so much the power going off, after all when you switch off
an electronic instrument it amounts to the same thing as removing the power.
The problem is that associated with power outages are usually spikes and dips
(brownouts).  Spikes can be many hundreds of volts above the nominal supply
which of cause can damage electronic components while brownouts cause greater
current draw which can lead to over heating and subsequent damage.

So for your UPS you should look to buy a unit that will stabilise the voltage
to the instrument not just provide power when the supply fails completely.
This is why they are expensive but it is good insurance and while I have no
numbers I would hope that those people with a UPS have a more reliable
instrument.

Also the longer you wish the UPS to supply power in the event of a failure the
bigger and more expensive it will be.  I would suggest that the UPS be able to
carry the instrument for 15 minutes and once it's power is drained, if
possible, require you to manually reapply power to the mass spec.  15 minutes
should get you over most short interruptions but if you have an hour long
electric storm you don't want the power being re-applied to the mass spec each
time the supply comes back.  Far better to wait until the storm has passed.

Cheers

Peter Stow

Bruce Hungate wrote:

> Dear List:
>
> My colleagues and I at Northern Arizona University are shopping for a
> couple of mass specs (Delta+, Optima, or Geo).  The building they will be
> in experiences around 6 power outages per year.
>
> How many of you have UPSs on your mass specs?  How bad is it for the mass
> spec if the system suddenly shuts down due to a loss of power, and is it a
> big deal to get them running again?  Would you recommend them, and how much
> do they cost? (I've heard around 7k, which seems high to me)
>
> Thanks.
>
> Bruce Hungate
>
> ____________________________________________________
> Bruce Hungate
> US Embassy/AID Mexico
> PO Box 3087
> Laredo TX 78044-3087
>
> [log in to unmask]
>
> After 17 August 1998
>
> Bruce Hungate
> Assistant Professor
> Biological Sciences
> Northern Arizona University
>
> [log in to unmask]



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