| Miniproposals | ||||||||||
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| Operators | |
| Session leader(s): | Ian Hutchinson |
| Physics operator(s): | Ian Hutchinson |
| Engineering operator(s): | Unknown |
| Engineering Operator Run Comment |
| Plasma attempts |
| Session Leader Plans |
| Physics Operators Plans |
| Session Leader Summaries |
| Entered: Jul 7 2004 03:49:06:663PM |
| Author: To Be Determined |
From: LEADER::HUTCH Date: 8-MAY-1993 17:36:47 Description: Summary of 8 May 93 run Summary of 8 may 93 run. 19 shots. Of order 3 shots on which all systems worked correctly. Engineering Problems 1. TF always crowbars, as ever. 2. OH1 power supply has some strange 60Hz oscillation. 3. OH2 power-supplies act strangely after crowbar. (Crowbar switched off now) 4. OH2-L periodically fails to commutate. 5. Substantial up-down asymmetries are present in EF1/OH2 during their initial ramp up. 6. Cooling valve leaking. 7. Vacuum leaks need attention. Dangerous Problem Number 4 above gives a very big upswing of the OH2 current. This reached as high as 29kA. (Shot 19). This level exceeds the current administrative limit of 25 kA, although not the design limit of 50kA. However, it illustrates that it would be dangerous to raise the currents in OH much above their present rather low levels in the present configuration. If the OH1 were to fail to crowbar, the peak OH2 current could be as high as 37 kA even now. This needs serious thought. Alternator worked very reliably. Well done on that! |
| Physics Operator Summaries |
| Session Leader Comments | |||
| May 8 1993 09:31:23:320AM | 930508001 | Ian Hutchinson | Hybrid was screwed up. thought that this was due to the test shots taken at
the end of yesterday. This was not the cause of the problem, though. Actually OH2 and OH1 and EF1 look OK till time -0.92 sec when OH1 starts to ramp down. OH1 had some board problems. This was an old fix that apparently had not got done to one bank of boards. Hopefully now fixed. |
| May 8 1993 10:34:45:720AM | 930508001 | Ian Hutchinson | Very similar to shot 1. OH1 starts to ramp down at -.82 sec.
Hybrid outputs still seem to be putting out garbage. But this does not seem to be the problem. Base pressure. 2e-7. Decided to zero the hyid and reprogram. |
| May 8 1993 10:41:00:780AM | 930508001 | Ian Hutchinson | Things went much better here, this is very like the last shot from
yesterday. OH2L has a downward ramp starting at about -37ms. this causes an imbalance and hence horizontal field. The behaviour is not consistent with the hybrid demand, which correctly rises to try to compensate for the growing mismatch. OH2L is not responding correctly to hybrid demand at this time. Incidentally, a complete reprogramming of the Hybrid seems to have fixed the craziness that had shown up on the other channels. Gas was apparently in the machine for this shot (asking 4e-4). |
| May 8 1993 10:43:09:340AM | 930508003 | Ian Hutchinson | Things went much better here, this is very like the last shot from
yesterday. OH2L has a downward ramp starting at about -37ms. this causes an imbalance and hence horizontal field. The behaviour is not consistent with the hybrid demand, which correctly rises to try to compensate for the growing mismatch. OH2L is not responding correctly to hybrid demand at this time. Incidentally, a complete reprogramming of the Hybrid seems to have fixed the craziness that had shown up on the other channels. Gas was apparently in the machine for this shot (asking 4e-4). |
| May 8 1993 11:14:19:480AM | 930508004 | Ian Hutchinson | Still have the OH2L problem. Everything else was as expected. NO field
null because of the decrease in EF1. So raised the EF4 voltage for the next shot by about 20%. |
| May 8 1993 12:07:46:530PM | 930508006 | Ian Hutchinson | Lowered the oh2 voltage preprogram to zero at the end of the ramp.
Previous shot had too much oh2 and it did not sag. Also too much oh1 as well. Got about 13.5 on Oh2. This seems quite good except for the imbalance which gives a forizontal field. This appears to be due to continuing OH2L supply problems. |
| May 8 1993 12:39:01:440PM | 930508007 | Ian Hutchinson | Raised gain from 1. to 1.5 on oh2 current feedback. Altered current
program a tad. Result: OH2L PS had the usual problem at -40ms and then did not commutate and was driven up to about 25 kA by the other commutations. Prior to the problems, we got close to what we asked for in the hybrid. So basically the hybrid programming is OK like this. |
| May 8 1993 12:45:24:890PM | 930508008 | Ian Hutchinson | Breakers stayed in. Ran only oh1,2.
OH looks ok prior to commutation. Crowbar is funny on OH2. Looks as if the oh2 problem might be cause by the others |
| May 8 1993 01:10:19:740PM | 930508009 | Ian Hutchinson | Breakers tripped. However, the currents in OH2 prior to commutation
look ok. The crowbar time is still screwy. Discussion suggests that the internal gain (times constant?) on the OH2 supplies from yesterday is too large (short?). This altered to match the timeconstant of the hybrid ~100ms in stead of ~20. |
| May 8 1993 03:39:23:800PM | 930508016 | Ian Hutchinson | Turned on oh1 feedback using the oh1 v-programming and s-current pasted
from 13? This appeared to work quite well (shot 15 had just the v but not the feedback). Power-supply 60Hz problem is being worked on and does not seem to be related to hybrid. Present configuation therefore has OH1,2 EF1 under current feedback control (Although only oh1 was on this shot). A slight worry is that currents are being driven in the Oh2s. (only oh2l last shot). This is thought to be due to the autocrowbar firing because of a high voltage appearing across the power supply during oh1 commutation. |
| May 8 1993 04:42:09:330PM | 930508017 | Ian Hutchinson | Everything back on. Horizontal field due to ef and oh mismatch.
There is a temperature mismatch that is possibly due to a cooling problem. |
| May 8 1993 05:13:59:640PM | 930508018 | Ian Hutchinson | Cut in the oh2 voltages into the programming.
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| May 8 1993 05:14:42:780PM | 930508019 | Ian Hutchinson | Almost exact repeat. Same problems arose.
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| Physics Operator Comments |
| Engineering Operator Comments | ||||
| Shot | Time | Type | Status | Comment |
| 1 | 09:02:44:130AM | Plasma | Bad | OH1 had 1 phase group missing; gate boards had not been upgraded to late |
| 2 | 09:43:28:090AM | Plasma | Bad | OH1 spurious fault >1 scr out; interlock jumped in master cab |
| 3 | 10:18:40:590AM | Plasma | Bad | OH1 went into inversion at -.037seconds; no fault indicated; no gate pul |
| 4 | 10:59:21:670AM | Plasma | Ok | All supplies worked up to blip; EF1 may be crowbared by too high commuta |
| 5 | 11:20:35:150AM | Plasma | Ok | All supplies good to blip; no flash; EF1 both show comm faults |
| 6 | 11:45:31:680AM | Plasma | Ok | good PF but no flash |
| 7 | 12:08:10:170PM | Plasma | Bad | OH1 and OH2U invert early; OH2U and EF1 bypass commutation failure |
| 8 | 12:35:20:510PM | Test | Ok | OH1 and both OH2's; everything OK |
| 9 | 12:45:32:750PM | Test | Bad | adding EF3 to OH1 and OH2 produced faults; pr4oblem may be OH2 voltage r |
| 10 | 01:23:29:670PM | Test | Bad | OH2L commutation fault |
| 11 | 01:40:57:110PM | Test | Ok | bad fuse in oh2l |
| 12 | 02:08:31:320PM | Test | Ok | cap bank test ok |
| 13 | 02:18:12:520PM | Test | Ok | OH1 AND OH2 commutation test ok |
| 14 | 02:48:09:720PM | Test | Ok | OH1 test still has 1 phase group missing |
| 15 | 03:05:54:370PM | Test | Ok | OH1 6-pulse test OK |
| 16 | 03:19:25:930PM | Test | Ok | OH1 6-pulse test shows strong 60-hz component |
| 17 | 04:09:33:950PM | Plasma | Ok | no flash |
| 18 | 04:46:58:810PM | Plasma | Bad | OH2U comuutation switch faillure |
| 19 | 05:03:58:140PM | Plasma | Bad | OH2U commutation switch failed |