Hi Scott,
TL;DR--my recommendation is to hire somebody to do this. See more
details below.
My knee-jerk reaction is that if you haven't done a lot of this stuff yourself,
trying to pull off a magnet move solo is probably not a great idea. First,
there are lots of mechanical details involved in moving magnets that might trip you
up. It's important to get things aligned properly and make sure that things
go back in the right orientations when you get the magnet sited. Additionally
you'd want to be extremely sure of the route you're taking if you're going from the
5th floor to the basement--if you're planning to move the magnet cold you want to
be sure that the route is EXTREMELY smooth so you don't risk snapping the alignment
rods in the magnet. And if you have somebody else do it they can likely do a
rebuild--if the magnets are around 14 years old, they might benefit from replacement
o-rings, etc. I don't believe Bruker is allowed to move magnets cold anymore
because of the risk of damage to the magnet.
"Whoever does this will be guessing" is also EXTREMELY significant.
Energizing a magnet without at least some idea of what the main and cryoshim
currents should be can be gnarlier than you might expect. If any of
the cryoshim currents are unusually high then if you just quench the cryoshims
before you ramp down the main field you risk quenching the magnet--if the
currents are too high it's better to ramp them down than to quench them.
And then when you bring the magnet back up there's a good chance that the water
peak will just be a weird blob with no real indication of what the shim currents
should be. This is not trivial to resolve. Bruker has a shim mapper
that we use in this case that works really well and lets us cryoshim magnets
from scratch but these are extremely rare. Anyway, bringing a magnet up
from scratch can be done but in my experience it requires somebody with a
significant amount of experience--they have gone through this process many
times and have a good feel for how it should go. If you haven't even done
one magnet solo before you're missing all that experience/intuition.
Also if you've got the magnet current wrong when you open the main switch you'll
immediately quench the magnet.
De-energizing and energizing a magnet is in general not super complicated but
there are a lot of nit-picky details that make the difference in how things go.
There are a lot of safety details to be concerned with and if things go wrong it's
important to be able to recognize what's going on and how to address it quickly.
A contractor should have their own insurance so if things go horribly wrong you'll
be covered that way as well. I'm not sure how your insurance works, but if
you hose it/them up due to lack of experience I suspect they'd be less inclined to
just buy you some new magnets.
I would recommend paying the extra $$$ to have somebody come in and do the job.
There's a WORLD of difference between "have participated in several" magnet
installations and "has been doing this for years/decades" (depending on who
you hire.) I think in this case your lack of experience is a major factor
for consideration and there's an extremely high level of risk of rendering any
or all of the instruments unusable. The email above definitely does not
cover all the things that could go wrong, but hopefully I've listed some of the
less obvious ones. (not including ice in the magnet, quenches, things
tipping over or getting dropped...)
However you end up choosing to do this, good luck.
Cheers,Mike
On Friday, February 14, 2025 at 11:36:45 AM MST, Smith, Scott K via groups.io wrote:
Hi y’all,
We are considering the move of three magnex 400’s (Varian/Agilent
MR400’s) from a 5th floor to the basement of the same building.
I am comparing costs of purchasing a new magnet powersupply <$20k and doing
it myself verses hiring one of the well known and competent after market
contractors in our niche. There is clearly a monetary incentive
to do it in house; there is also a logistical incentive with respect to doing
it completely on our own timeline where delays of any kind cost nothing.
While I have not soloed a magnet installation, I have participated in several
and I have (hopefully not unjustified) a pretty high opinion of my
technical/mechanical intuition.
Complications: I came to this lab recently and have been unable to find more
than one magnet installation document with amperes, polarity and shim currents.
So whoever does this will be guessing. The three magnets are in one room.
One of them definitely was charged with positive polarity, some ancient memory
tells me that perhaps the polarities were inverted between them to mitigate
cumulative interaction…. They were installed ~2011-2012 and are positioned >10’
from each other. The middle one is positive. =
I searched our emails from the last four years for “magnet power
supplies” and found nothing useful. I am going to conclude
that not many of us have undertaken this job and those that might have are
keeping it a secret. So I am seriously considering buying a power
supply and taking on this task.
What say my peers? I am curious. What distribution
of encouragement and condemnation will arise from your opinions.
If I get more than a handful of responses I will report my findings.
“Keep `em flying”
Scott
Scott K. Smith,Director of NMR Spectroscopy
The University of Texas at Austin | Chemistry | 832-294-1928 | utexas.edu
NMRlab homepage:IoNMR | Nuclear Magnetic Resonance Labs (utexas.edu)
-=-=-=-=-=-=-=-=-=-=-=-
Groups.io Links: You receive all messages sent to this group.
View/Reply Online (#2041): https://urldefense.com/v3/__https://ammrl.groups=
.io/g/main/message/2041__;!!PvDODwlR4mBZyAb0!Uc52eb4S72ItFxe9fm-m0HoK4KaGxh=
Mo_XAPYqygBX3V-XMvfNhvd2SoNpIjExwFXWKTuxgqfuvCkPKIf5zEfMP7tLzI$
Mute This Topic: https://urldefense.com/v3/__https://groups.io/mt/111187656=
/7559972__;!!PvDODwlR4mBZyAb0!Uc52eb4S72ItFxe9fm-m0HoK4KaGxhMo_XAPYqygBX3V-=
XMvfNhvd2SoNpIjExwFXWKTuxgqfuvCkPKIf5zEfLGaNyzQ$
Group Owner: main+owner_at_ammrl.groups.io
-=-=-=-=-=-=-=-=-=-=-=-
Received on Tue Feb 18 2025 - 07:04:58 MST