Alcator C-Mod Run 930505 Information

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Miniproposals
Miniproposal:
Date Filed:
Title:
First Author:
Session Leader:Steve Golovato (shots 1-9)

Operators
Session leader(s):Steve Golovato
Physics operator(s): Unknown
Engineering operator(s): Unknown

Engineering Operator Run Comment
TF tests; if successful, then plasma attempts

Session Leader Plans

Physics Operators Plans

Session Leader Summaries

Physics Operator Summaries

Session Leader Comments
May 5 1993 02:57:46:030PMSteve Golovato
13.8 problem isolated to EF3 supply, noise identified as arcing
only occurred with EF3 connected to the 13.8, but before the DC
side is turned on.

Listening at all power room doors indicates that the sound (clicking)
is loudest toward the cell, not toward the street where the EF3 supply
is located.

Will do a few more TF test shots and then stop to further investigate
problem.



May 5 1993 03:32:21:160PMSteve Golovato
Ran another EF3 test to "listen" with AM radio. No noise heard
by radio nor by human "listeners". Seems to have gone away.

So we're going back to running with all systems, at least until
the noise comes back.

May 5 1993 04:04:30:840PMSteve Golovato
Problem fixed. Soleniod driven by solid-state relay which was being switched
by electrical noise presumably generated by EF3 supply.


May 5 1993 09:22:00:250AM930505001Steve GolovatoTF test. 30 kA, ~1.3 T. Two TF cabinets operational.
Got 30 kA, pulse not long enough.

May 5 1993 09:43:46:510AM930505001Steve GolovatoSame shot as 1, longer pulse.
Panic button hit near end of pulse, machine operator wasn't informed of
longer pulse. Got 56 kA, 2 T.
10 minute halt to change commutation resistors and look at TF supplies.


May 5 1993 09:46:52:950AM930505002Steve GolovatoPrevious entry was for shot 930505002, not 930505001.

May 5 1993 10:58:11:300AM930505003Steve Golovato
All magnet supplies turned on (except EF2, EFC) using Wolfe's
voltage waveforms (PCS mode 1011). OH2 commutation resistor 0.032.
No feedback.
TF still at reduced level.
Gas fill on at 4 X 10-5.

Everything ran.
OH2 strange after commutation.
EF1 voltage low.


May 5 1993 11:13:13:300AM930505004Steve Golovato
TF to 100 kA.
Feedback on for EF1U&L current.
EF1 voltage waveform changed, started earlier to get up to desired current.
Hybrid changes did not get in for this shot. Load still occurring when state
went into init.

Shot screwed up, likely because hybrid not loaded correctly.
Only TF ran and it crowbarred.




May 5 1993 11:19:28:820AM930505004Steve Golovato
Wavegen did not get start trigger, no program to any coil.
Cold start of hybrid done just in case.



May 5 1993 11:39:14:540AM930505005Steve Golovato
Repeat of last shot, hopefully with everything working.

TF crowbarred.
Alternator tripped early, all currents start down at -0.3 sec.
Still not getting desired current in EF1.



May 5 1993 11:57:36:610AM930505006Steve Golovato
Got 3.5 T TF last shot.
EF1 PS overpowered by close coupling to OH, cannot get to desired current.
EF1U&L started earlier (-1.2 sec), run flat out early.
Pulsed gas 50 V for 40 ms (was 40 V last shot) at 0.5 sec

Shot aborted. Apparently 13.8 arcing.


May 5 1993 03:21:52:620PM930505006Steve GolovatoTF only, set for 100 kA.
Got 98 kA (3.4 T), supply crowbarred.
Using AM radio to "listen" for arcing, got no pickup (EF3 off).


May 5 1993 03:51:17:610PM930505007Steve GolovatoNo gas. Sound back, faster, sounds more like a relay than an arc and
more definitely on cell side of power room. No noise on radio.
Shot aborted. No data.

May 5 1993 04:13:28:660PM930505007Steve Golovato
All on, including gas. TF crowbarred.
Gas pre-fill 4 X10-5, pulse 30 V for 40 ms at 0.5 sec.
EF1 still low. This time because alternator tripped at -0.4 sec
because of TF crowbar.

May 5 1993 04:52:07:250PM930505008Steve GolovatoTF crowbarred. Wavegen didn't fire, but had matrix switching. No demands
on PF supplies. Not clear why.

May 5 1993 04:53:36:440PM930505008Steve Golovato
Gas to 40 V.
Delay to enter cell, check on LN2 pump,which shut down.


May 5 1993 05:08:40:290PM930505009Steve Golovato
TF set to 50 kA, regulated, then crowbared at the end.
Hybrid ran.

May 5 1993 05:18:11:830PM930505009Steve Golovato
EF1L crowbarred.



May 5 1993 09:01:50:710AM930505029Steve GolovatoBase pressure high ~10-7 torr.
Commutation resistors:
OH1 0.127 Ohm
OH2U&L 0.069
EF1U&L 0.205


May 5 1993 09:05:51:160AM930505029Steve Golovato #2 5-MAY-1993 08:44:55.04 NEWMAIL
OH1, OH2U&L, EF1U&L and EF4:
ON= -.60 sec
CLOSE= -.55
OPEN= 0. (OH1,OH2U&L,EF1U&L only)
CROWBAR=0.030 (OH1,OH2U&L,EF1U&L only)
INVERT= 0.250
EF3:
ON= anytime before -.050 sec
INVERT= +.250
EF2U&L each have ballast resistor = 35e-3 Ohm (not critical)
ON= anytime before 0.0 sec
CLOSE= 0.030
INVERT=0.250
PLC current limits at or above drawn waveforms, eg
OH1 22kA
OH2U&L 17kA
EF1U&L 12kA
EF2U&L 5kA
EF3 12kA (supply current)
EF4 4kA
The plasma is assumed to breakdown at 0.020 sec, and
rise at 1.e6 A/sec.


Physics Operator Comments

Engineering Operator Comments
ShotTimeTypeStatusComment
109:09:52:870AMTestOkTF pulse; 30 kA with no flat top, some question about high tap gates
209:23:34:970AMTestOk55 kA TF; no high tap gates
310:26:49:420AMTestBadAll power supplies except EF2U&L and EFC; Commutation Failure on OH2L
410:59:44:960AMTestBadTF Crowbar due to IOC setpoint error
511:21:04:480AMPlasmaBadTF crowbar at inversion; -.1 seconds; set to +.1 seconds for next shot
611:51:58:290AMTestBadTF crowbar at begining of flat top
703:40:41:230PMPlasmaBadTF crowbar at 70 kA; found 1 TF cabinet gate drives off
804:37:18:030PMPlasmaBadTF Crobar at 60 ka
904:59:51:450PMPlasmaBad50 kA TF OK, PF tripped on commutation failure