The procedure to recover a quenched magnet is extensive, and requires much more than just a single power supply. Just to test it for viability, you need an energisation lead, shorting plug removal tool, and the magnet manual specific for that magnet serial number. If the magnet passes room temperature resistance tests, you then need a gantry, hoist, magnet seals, vacuum pump, leak tester, blowout tube, liquid helium transfer line, shim power supply, SC switch heater power supply, and many other accessory pieces of specialised cable and tubing in addition to a magnet power supply. This is not a job for you to succeed without hiring a professional magnet service engineer, which will cost much greater than $10,000.

You also need to test the AQR to see if it operates. That means testing each power supply and cooling fan, the host computer and software, then the remainder of the electronics.

"Always look a gift horse in the mouth!" (You might find no useful teeth.)

Replacing magnet seals and that sort of thing would be a good idea too. We recently did this (with the help of the Bruker engineer on-site), and it was a major job. Not one to do without the engineer and the correct power supply (which is not a normal standard thing, but a big monster with huge cables that weighs a lot). Your magnet needs the correct charging rod (there are quite a few different ones), and you will probably also need fittings to pump it down again (unless it is a really really old (pre-1990-something) one where the fittings were built into the magnet.

At the helium price around here the quenches we didn't have during recommissioning and the helium we will save because the magnet is optimally put together pretty much covered the cost of the engineer.

If it was decommissioned properly then in the magnet manual there should be a discharge record. There should also be a charge record, from when it was first charged, which is helpful for recharging. If you can find the manual it would tell you if it was discharged correctly - which might also help you work out if it is worth resurrecting.

Kate

The primary knowledge you need is a copy of the magnet manual for that specific coil. A Bruker magnet manual will be titled “SC-MAGNETSYSTEM”, and the coil number is on the label on the side of the magnet. You may contact Bruker to receive a copy of the manual if it is not with the system. Bruker NMR magnets are not high-current. A 650 ampere power supply is not necessary. 100 amperes is likely more than sufficient. There are also 3 power supplies needed, not just one. The internal structure important for electrical connections and for vacuum connections , as well as the power supply requirements are detailed in the manual, and the precise currents needed to approximately reach the field homogeneity necessary to do NMR are also detailed in the manual for that coil number. Even before filling with liquid helium, there is an internal siphon connection which must be reached to remove contamination from the helium chamber. This is why you need a magnet manual – to know what pieces and parameters are required.

The most import piece of equipment is the energisation lead (also called a stick or rod). There is NOT a detailed diagram of the stick dimensions in the manual. The stick contains superconducting wire, and it is not possible to measure the mating connector, so a stick is not practical to fabricate. If this item is not in hand with the magnet, it simply cannot be operated. Before you seek a power supply, you need a Bruker magnet energisation stick and the magnet manual. Then you will be able to test the magnet and shim resistances at room temperature to know if it might be damaged electrically.

Without newly installed cryostat vacuum seals, the magnet will require an excess amount of cryogens to maintain operation. One cannot operate an NMR magnet cryostat while attached to a vacuum pump, because the liquid helium evaporated gas travels backward through the vacuum pump by means of cryopumping. Evaporated helium gas also enters easily through even the smallest of seal leaks, soon making the cryostat impossible to operate due to helium gas contamination of the vacuum insulation. When helium gas contamination reaches the superinsulation layers within the cryostat, it cannot be removed and spoils the vacuum insulation of the cryostat forever. Before attempting energisation, I recommend to install new vacuum seals and test thoroughly for leaks with a helium leak detector.

In addition, you must have reliable delivery and funding to buy cryogens. Approximately 50 liters of Liquid Nitrogen are required every week. Approximately 100 liters of Liquid Helium are required every 6 months. In addition, several hundred liters of both LN2 and LHe may be needed for each quench or energisation.

Only until you have a reliable cryogen supply, the magnet manual, an energisation stick, and a reliable vacuum seal, can you hope to operate a magnet power supply.