0.7 mm crash statistics

Hardware
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1

Share here your 0.7 mm rotor crash experience

2

Utrecht, NL

We used the 0.7 probe 3 times:

  1. Acceptance tests - arcing - back to factory
  2. Acceptance tests - rotor crash - back to factory
  3. First time use after acceptance - rotor crash - back to factory

Both rotor crashes occurred with fresh rotors, labelled UROS. Both times Bruker replaced coil and stator.

Probe 0.7 mm PH MASDVT1200S6 BL0.7 N/C/H NO_I/E

3

Frankfurt, BMRZ, Germany

  1. Aug 2021 850 WB - brand new rotor - coil damaged
  2. Okt 2023 850 WB - due to power outage - coil damaged
  3. Jan 2024 Rotortester - due to VT flow > 300l/h - no damage, crash was at low speed around 30 kHz
  4. Feb 2024 1.2 GHz SB - first use after Acceptance - new rotor, that was delivered with the probe - coil and stator damaged
4

On which probe was that? 1.2 GHz? Do you know what was damaged during the crashes, just the coil or also the stator?

5

Yes, it happened with 1200 probe and they replaced both coil and stator AFAIK.
I added info to the post.

6

Here are our statistics for a series of crashes we have had over the last two years at ETH Zurich:

850MHz WB probe:
Crash occurred during spin up at 70kHz MAS. Rotor was not new.
Coil was replaced in house (coil cost: 3123 CHF from Bruker) (1 day repair time).

850MHz WB probe:
Crash occurred due to failure of the bearing connection at 100kHz MAS. Rotor was new.
Coil was replaced in house (coil cost: 3123 CHF from Bruker) (1 day repair time).

850MHz WB probe:
Crash occurred while spinning at 110kHz for unknown reasons (spinning was stable up until the crash). The rotor was not new and had spun stably (with the same sample) on previous occasions. (repairs are ongoing).

1.2GHz SB probe
Crash occurred due to failure of the bearing connection at 100kHz MAS. Rotor was not new.
Coil and stator were replaced by Bruker (~5month repair time).
Cost: 23123 CHF coil + stator and 6000 labor.

1.2GHz SB probe
No crash but stator no longer spins. Reason is unknown and repairs are ongoing.

We have resorted to doing much of our own repairs to save both time and money, particularly when it comes to just damaged coils as these are very straight forward to repair. If anyone is interested in this I am more than happy to share how we do this. We do still purchase the spare coils from Bruker.

7

Thank’s a lot for your report. It is interesting to see that you had crashes in the WB probe which “just” required a new coil and the crash in the 1.2 GHz SB probe resulted in stator damage which is very similar to what we observe.
Scince you had the problem twice: Did the bearing connection fail inside the probe or was there some external problem?
Good to hear, that chaining the coil is something that could be done on side.

8

Interesting that you have also seen the 1.2GHz stators to appear (at least so far) a bit more fragile to crashes. Not sure why, technically the stators should be identical.
In regards to the bearing line issues these were all external connection failures and all user errors. They were improperly connected, one was actually caused by Bruker changing the bearing/drive connections over (as we have two types of probes with either combined or separate bearing sense connections).

9

One thought I had with regard to SB vs WB 0.7 mm probes is, maybe the difference is that the stator is open and not closed by this screw. This might offer same space for the rotor parts in case of the rotor crash.
Thanks for clarifying the bearing problem. We also have to change the bearing connection depending on the type of probe and it is good to know that this can cause such problems.

10

I would like to give you an update on our 0.7mm 1.2 GHz probe after the crash in Feb 2024:

  • Nov 2024: Reinstalltion, crash during reinstalltion by Bruker
  • Feb 2025: Reinstalltion, crash during reinstalltion by Bruker
  • May 2025: Successfull reinstallation. Before this some changes were done to the probe and Bruker thinks it is due to these changes that the probe is working now. Let’s hope is continues to work. Most of the time we run solution on the 1.2 GHz thus it will take some time so see how robust it really is.
  • The first repair in Nov24 was payed by us, but after the trouble with reinstalltion Bruker refunded this. In summary, it took a long time to get thing to work, but we didn’t have to pay the repairs.