| Miniproposals | ||||||||||
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| Operators | |
| Session leader(s): | John Rice |
| Physics operator(s): | Steve Horne |
| Engineering operator(s): | Frank Silva,Joe Daigle |
| Engineering Operator Run Comment |
| plasma run. activate ef2 tmx supplies |
| Session Leader Plans |
| Physics Operators Plans |
| Session Leader Summaries |
| Entered: Jul 7 2004 03:49:07:070PM |
| Author: To Be Determined |
Run Summary 930514 Physics -- Horne, Rice Engineering -- Frank Silva, Joe Daigle Consultants -- Tony Taylor and Tom Osborn, from GA. An interesting and eventful run. The consensus after the last run was that using the EF2 supplies would significantly improve the null. We began with feedback control of all systems except EF3, including EF2, and tried to hit a specified "target" set of currents 5 msec after commutation. EF2 switch was initially closed very late after commutation, to get a handle on the current rise. We did well enough on the first shot to get a blink. Thereafter we moved EF2 into the shot and tweaked and got a plasma again on shot 5. Further tweaks got us to 25 ka on shot 12, which the ultra-long wavelength x-ray arrays showed a single current channel. Further adjustments, primarily of vertical field, led to shot 18, which was a new current record at 29.7 KA. We dropped oh2 commutation resistance a bit and got 27 KA on shot 20. Things deteriorated from there. Power supplies ran very well. There is a fault which occurs in OH2 L when it is inverted hard but it didn't seem to stop us. Computers ran well, with minor glitches. Feedback worked routinely. Lessons Learned: 1) Great care should be taken to ensure that the PLC current limits are set well above the currents we want. A rule of thumb might be 3000 A or 20% of required current, whichever is greater, above the required currents. If you suspect a power supply is mostly working but seems very slow, raise the plc current limits. 2) Don't wait till 4:00 PM to do the gas scan. It won't happen. Next time we hit 29.7 KA let's do a gas scan. |
| Physics Operator Summaries |
| Session Leader Comments | |||
| May 14 1993 09:48:33:550AM | 930514001 | John Rice | Session Leader: Steve Horne
Engineering Leader: Steve Fairfax Droog: John Rice Theme of the run is still the search for the 100 kA holy grail. Target currents for shot 001: ef1u 3100 ef1l 3100 ef2u 1200 ef2l 1200 ef3u -600 ef3l -600 ef4u 700 ef4l 700 efcu 0 efcl 0 oh1 10000 oh2u 12000 oh2l 12000 tf 5T gas h2 8e-5 commutation resistors: oh1 156 mohm oh2 46 mohm ef1 250 mohm ef2 ballast resistor: 40 mohm plc current limits: ef1 6000 ef2 2000 ef3 1000 ef4 1000 oh1 13000 oh2 16000 weak flash 10 kA Ip breakdown late, 10 ms duration 'a miracle occurred' |
| May 14 1993 09:55:38:820AM | 930514002 | John Rice | changed switch time of ef2 +20ms
ef3 voltage changed to reduce effect on ef2 oh1 current dropped 2 kA no flash |
| May 14 1993 10:32:15:160AM | 930514003 | John Rice | stack is where it is wanted
further tweaks in other coils, ef1 needs adjusting ef1 voltage dropped to 75 at -800 ms turning on feedback for ef2s 200 ms time constant no flash |
| May 14 1993 10:41:12:010AM | 930514004 | John Rice | fixed programming errors
ef2l was being controlled by ef2u programming, now fixed goetz shot 43 front 51 back graf 51 front 46 back no flash ef1 current still too high ef2 fed back nicely ef3 looks fairly good ef4s imballanced ef4l drifting too much vertical field |
| May 14 1993 10:54:25:290AM | 930514005 | John Rice | ef1 current dropped from 4000 to 3000 at commutation
wimpy flash 'groping in the dark' within 200 A of requests breakdown where Bz crosses 0 dBz/dr sucks tv channel 16 now tangential view |
| May 14 1993 11:07:13:920AM | 930514006 | John Rice | ef3 voltage pulled more negative to control Bz,
ef2s are going to get hammered got the flash, very wimpy, 10 ms duration |
| May 14 1993 11:29:14:730AM | 930514007 | John Rice | fixed ef3 programming
flash, 15 ms |
| May 14 1993 11:44:30:390AM | 930514008 | John Rice | preprogramming for ef2s is approximately what was attained last shot
preprogramming anticipating demand, moved back in time lost it, no flash |
| May 14 1993 11:50:01:980AM | 930514009 | John Rice | preprogramming for ef2 leading by 20 ms
tweak on ef3 no flash |
| May 14 1993 12:12:32:700PM | 930514010 | John Rice | ef3 current limit set to 10000
ef4 voltage changed from -3000 to -2500 flash, late at 30 ms, 15 ms duration, 10 kA, breakdown at 9 V some oh1 problems |
| May 14 1993 12:26:35:970PM | 930514011 | John Rice | with an exquisitely delicate calculation, have determined that the voltage on ef3
should be dropped at -2 ms from -300 to -230. the idea is to reduce slightly the current in ef3 at commutation. no flash |
| May 14 1993 12:53:52:120PM | 930514012 | John Rice | access violation during wavegen init, allegedly fixed
flash, 35 ms, 20 kA, 'looks more like a single current channel than anything we've had' 'mickey mouse head null' |
| May 14 1993 01:03:49:270PM | 930514013 | John Rice | another delicate tweak to ef3 at -2ms, now at -100 V
change to ef4, moved inversion pulse to -20 ms flash, broke down early, 35 ms long, 10V on CII, 20 kA |
| May 14 1993 01:23:42:600PM | 930514014 | John Rice | repeat, raised plc current limit of ef4
no flash, too much ef4 |
| May 14 1993 01:42:29:460PM | 930514015 | John Rice | changed preprog on ef4 to reduce current at commutation, and reduced the ef2
inversion voltage from -160 to -84 flash, 30 ms long, 'looks like Orion' feedback is fighting the voltage on ef4 |
| May 14 1993 01:56:20:840PM | 930514016 | John Rice | tweak to ef4, in same direction as previous, still too much Bz
flash, 40 ms long |
| May 14 1993 02:06:54:470PM | 930514017 | John Rice | anti-inverting oh2 by +100V,
ef4 prog coming down to -10V from +20V flash, 35 ms |
| May 14 1993 02:23:17:890PM | 930514018 | John Rice | changed ef4 prog current from 700 to 650A.
flash, 30 ms long, new current record, 30kA |
| May 14 1993 02:46:57:800PM | 930514019 | John Rice | reduced oh2 commutation resistor from 46 mohm to 30 mohm.
changed ef4 prog reduced from 650 to 600 A. flash, 20 ms long, 16 kA |
| May 14 1993 03:02:08:970PM | 930514020 | John Rice | ef1 currents dropped by 600A from 3000 to 2400 and ef4 raised to 700A.
flash, 20 ms, 27 kA, Bz still positive 'Monty Python dead parrot' |
| May 14 1993 03:21:22:590PM | 930514021 | John Rice | changed voltage programming at the appropriate time to the appropriate value,
in order to tweak the currently unfavorable field index. flash, 20 ms, 20 kA, gradient 0 at 20 ms. |
| May 14 1993 03:33:34:240PM | 930514022 | John Rice | 60A more Bz
same corrections for oh2s (-60V), ef4s raised by 50A to 740A. flash, 25 ms, 20 kA forgot to prog oh2u |
| May 14 1993 03:43:43:160PM | 930514023 | John Rice | oh2u now prog like oh2l
Bz will be more negative flash, 40 ms, 15 kA 'who could ask for a better Bz than that?' |
| May 14 1993 04:01:39:290PM | 930514024 | John Rice | 200A less current in ef1s
flash, 35 ms, 22kA |
| May 14 1993 04:26:09:800PM | 930514025 | John Rice | turning on oh1 hard
wimpy flash, 30 ms, 15kA |
| May 14 1993 04:37:55:130PM | 930514026 | John Rice | did what was wanted but too much of it, half this time. 'you definitely have your hand
on the right knob.' oh1 lowered 350V. flash, 35 ms, 15 kA, drifting downward |
| May 14 1993 04:57:23:770PM | 930514027 | John Rice | lowered ef4 by 50A
flash, 35ms , 20 kA |
| May 14 1993 05:12:50:610PM | 930514028 | John Rice | make Bz ramp down more slowly by increasing EF3 by 300V (making it less negative).
Also increased voltage on OH1 by 300V at 12msec. flash, 15msec, 17.5kA |
| Physics Operator Comments |
| Engineering Operator Comments | ||||
| Shot | Time | Type | Status | Comment |
| 1 | 09:27:45:630AM | Plasma | Ok | shot 1 bd, ef2 ok |
| 2 | 09:53:26:670AM | Plasma | Ok | #2 no bd |
| 3 | 10:14:03:100AM | Plasma | Ok | no bd, ef2 prog. XX |
| 4 | 10:33:55:540AM | Plasma | Ok | |
| 5 | 10:45:24:350AM | Plasma | Ok | bd |
| 6 | 11:00:58:690AM | Plasma | Ok | bd ok |
| 7 | 11:16:14:240AM | Plasma | Ok | breakers out bd |
| 8 | 11:32:57:190AM | Plasma | Bad | com fail oh2l, ef1 bd |
| 9 | 11:46:02:000AM | Plasma | Bad | oh2l comm. fail nbd |
| 10 | 12:00:32:830PM | Plasma | Bad | OH2L com fail |
| 11 | 12:19:49:530PM | Plasma | Bad | no pf |
| 12 | 12:38:49:590PM | Plasma | Ok | Break down PF Breaker Pulled out look like an oh2 L com Fault. |
| 13 | 12:56:21:130PM | Plasma | Ok | Good Shot |
| 14 | 01:14:19:170PM | Plasma | Ok | OH2L looks like it is single phasing but PF breaker did not come out. |
| 15 | 01:34:06:900PM | Plasma | Ok | Breakdown, Power Supplies OK. |
| 16 | 01:48:02:860PM | Plasma | Ok | Plasma Breakdown No Power Supply Faults. |
| 17 | 02:01:04:540PM | Plasma | Ok | Plasma Breakdown PF System OK |
| 18 | 02:13:50:000PM | Plasma | Ok | Plasma Breakdown Pf System OK. |
| 19 | 02:37:20:960PM | Plasma | Ok | plasma Breakdown PF system OK. |
| 20 | 02:52:40:870PM | Plasma | Ok | Plasma Breakdown PF system OK. |
| 21 | 03:14:14:650PM | Plasma | Ok | Plasma Breakdown Power supplies OK. |
| 22 | 03:28:29:960PM | Plasma | Ok | Good |
| 23 | 03:35:32:070PM | Plasma | Ok | Plasma Breakdown Power Supplies OK. |
| 24 | 03:55:22:010PM | Plasma | Ok | Plasma Breakdown Power Supplies OK. |
| 25 | 04:20:42:750PM | Plasma | Ok | Plasma Breakdown Power Supplies OK |
| 26 | 04:33:13:130PM | Plasma | Ok | Plasma Breakdown Power Supplies OK. |
| 27 | 04:53:00:390PM | Plasma | Ok | plasma Breakdown Power supplies OK |
| 28 | 05:06:14:970PM | Test | Bad | |