[Hallb-engineering] [New Logentry] Follow-up Re: Follow-up Re: Hall B Torus/Solenoid Force Interaction Studies

[kashy at jlab.org]

Logentry Text:
--
Once again we saw stong electro-magnetic coupling between the Torus and Solenoid. As the Solenoid ramped down with Torus at full negative field the OOPS sensors changed dramatically with Coil E dropping~50%  from 1390lbs to 719 while others fell and others rose.

We were going to wait 10 minutes before beginning the Torus rampdown, but 8 minutes into the hold period the Torus MPS decided to start ramping down the Torus. Nick found that there is "spare interlock" in the Danfysik power supply, that we are not using, but the power supply apparently is. This rampdown is not a normal "controlled" rampdown, we see that the rampdown rate is not increasing per the defined slew rate schedule. Nick reports that something like this has happened on the Hall D power supply and the transistors overheated and parts needed to be replaces.


DO NOT RESET THE POWER SUPPLY UNTIL THIS HAS BEEN INVESTIGATED. WE SHOULD CONFIRM THE FIRST BIT TO FAULT LOCALLY AT THE POWER SUPPLY WHEN THE HALL IS OPEN! WE MAY WANT TO HAVE DC POWER GROUP LOOK AT THIS ON THE INITIAL LOOK.

Upon further review of the data during these tests, it is fairly obvious that the Y supports of the Torus should see more effect from the solenoid than the Z since the Solenoid effects the OOPS and the OOPS act mostly in the Y direction for 4 of the 6 coils. 

The Torus may require a fast dump once the current is below 100 amps to get it to zero in a reasonable time. Below this current we should not blow any relief valves and should not have to go to warm return to recover it. 



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This is a plain text email for clients that cannot display HTML.  The full logentry can be found online at https://logbooks.jlab.org/entry/3486146
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