Eddy,
Thank you for your tips and experience. What kind of insurance have you signed
up for to protect a magnet from failing to come back up after a fully rigged
and stabilized move.
I was under the impression that contractors stay well away from promising a
replacement if the magnet fails to come back up. Also, you mention, that a
magnet quenched during a move. Was that move while energized or did you simple
mean the during the energization step of the magnet after the move?
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 https://ionmr.cm.utexas.edu/
> From: main_at_ammrl.groups.io On Behalf Of Eddy, Nicholas via groups.io
> Sent: Friday, February 14, 2025 2:38 PM
> To: main_at_ammrl.groups.io
> Subject: Re: [AMMRL] Pros and Cons of doing a magnet move in-house
Hi Scott,
I'm making some drastic assumptions with your comment of going it solo on this,
so please gloss over anything that isn't correct. The long and short of what's
below is, I'd recommend the engineer for two reasons: 1) insurance if something
happens to the magnet in the move and 2) less difficulty doing the job in a
reasonable time frame given the hardware requirements and other costs for the job.
Two cents from my experience with magnet moves, and this is likely real limited
to my specific case. Not all rigging companies are experienced with magnet moves,
even warm ones, and that can pose a risk to the magnet coming back online. If
you go external for the riggers, I suggest you vet them for that experience. If,
and this is a big if, you want to do this part yourself, check with a magnet
engineer that you're friendly with for what you need to have on hand. The hoist
and tripod should be well above the magnet weight to carry the load, and it's
easier done with extra hands on deck for the legs. Make sure that the tripod
legs get locked in place so they can't move. For the move of my magnets, we
had three people setting the magnet legs while I was adjusting the magnet up
and down on the hoist. On a whim long after the move, I looked at the price
of a hoist and tripod sized for my magnets and it was in the $20k range. I
strongly suggest if you're looking at going it alone on this part, get all
the numbers for everything you need. Definitely check on what pallet dimensions
you need for your magnet if you're building that in house. Pallet jacks are
preferred over fork lifts, from what I recall.
There are two ways you could do a short move like this, warm or cold. It's
going to depend on helium availability in your area which way you go, of
course. If you've got the budget to do a warm move and you know how to put
the shipping restraints in, do it that way. It's the safest for the magnets,
and I'd wager every single one of the engineers and companies in our field
would say to go this route if you can. If you don't, keep the magnet upright
and go slow. I'd say you'd benefit from the winter, but Texas doesn't get
as cold as Connecticut, so you won't have our benefit to the temperature
keeping helium around for a cold move. After the move, have extra helium
around. You can quench anytime during a charge, and that extra helium will
be necessary to get things back to cold or just keep them there. My Bruker
books all give an amount to have around for charging. We only kept 400 L on
hand in case of one magnet fully quenching during the move and warming up,
which was a gamble. Is the new lab equipped with a helium recovery unit? That
will help offset some cost of helium if you have it ready to capture the
fill boil off.
Power supplies are a commodity from what I've been told. They're expensive,
and have some quirks for what PS is needed for what size and type magnet
depending on the current it runs. If you are seriously considering on this,
check with an engineer on where they got theirs and what you may need for
your magnets. You may get answers; I believe I was told they run in the $35-50k
range if it's available. Things will be easier if you have the charging leads
for your magnets. Given that you would have a power supply and the leads, it's
really just a matter of putting the stick down the magnet and at taching the
leads. Run in the charge; I believe we cycled cryoshims when we did main coil
for both magnets (newer 2012 and older 1994). Check with an engineer on the
main coil current for your magnets, if you can. I'm willing to bet some
engineers know it without looking at notes. Watch your proton come in as you
ramp your current. Hit your cryos and adjust the currents to what you need.
Room environment matters. If you've got a steel beam running near the magnet,
your currents can be different than the book values. That happened on one
of my magnets, but again, that's a real specific case. Since you've said
you can't find much in the way of amperages in your documents, you're going
blind anyway. Consult your friendly engineer for tips and tricks on cryoshims
when they go in blind. I'd wager they have a few if they've been in the
business long enough. And make sure you have the correct cables rated for
the current load and connectors appropriate for your charging leads. We
used a water sample for cryoshims, which gives a broad singlet. I think
you're looking for a width of ~100-200 Hz FWHM and 500 Hz at the base,
bottom may be ok at 1 kHz. Check with an engineer to confirm my memory
on these numbers. We just looked at some cryoshims here on a few magnets
not so long ago, and those were the numbers that I recall off hand for
what we considered good. Watch drift until it stabilizes, and then do your
RT shims.
I've got a vague memory on a conversation with the engineer that I typically
bring in that some power supplies that were used for the older magnets aren't
sold anymore, so trying to find one may just drive you to using an engineer
anyway. That's probably a very specific type of power supply and may not be
the style you're looking for, so don't take that as a don't try. Overall,
I'd recommend the engineer to do the job because it will ultimately save
you the headache of the charging and shimming at the end, as well as dealing
with the hardware headache of the rigging. If you've got one that would work
with you, you can probably do the room temperature shims on your own and
not have that second visit after the magnets stabilize.
I hope this helps.
Best of luck,
Nicholas Eddy
Research Associate I
Institute of Material Science
25 King Hill Rd
Storrs, CT 06269
Office: (860) 486-2568
-=-=-=-=-=-=-=-=-=-=-=-
Groups.io Links: You receive all messages sent to this group.
View/Reply Online (#2044): https://urldefense.com/v3/__https://ammrl.groups=
.io/g/main/message/2044__;!!PvDODwlR4mBZyAb0!R9EwtbuW7ALX49f544oX4AVOzkEX_k=
6HSdNNImddEZj8P4iqq77l0lVarl5MCs4mfC03O5OHMZSaqPd7v6ZNz1ROzjSm$
Mute This Topic: https://urldefense.com/v3/__https://groups.io/mt/111187656=
/7559972__;!!PvDODwlR4mBZyAb0!R9EwtbuW7ALX49f544oX4AVOzkEX_k6HSdNNImddEZj8P=
4iqq77l0lVarl5MCs4mfC03O5OHMZSaqPd7v6ZNz6SkhEon$
Group Owner: main+owner_at_ammrl.groups.io
-=-=-=-=-=-=-=-=-=-=-=-
Received on Tue Feb 18 2025 - 12:08:01 MST