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6 th April 2010 MP3 weekly summary – issues and follow-up 0v1 M. Zerlauth for the MP3-CCC shift crew
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M. Zerlauth for the MP3-CCC shift crew. 0v1. Summary of the events during past weeks. Few additional issues discovered and solved by interventions done during the week Dominating issue is still with unexplained RQD/F trips in S12 and S78. RCO.A56B2 /RCD.A56B2. - PowerPoint PPT Presentation
Transcript of 0v1
6th April 2010
MP3 weekly summary – issues and follow-up
0v1
M. Zerlauth for the MP3-CCC shift crew
Summary of the events during past weeks
Circuit(s) Problem Intervention in field Remarks RCO/RCD.A56B2 Tripped again 3 times
during the week (total of 8 now!)
Not yet done… In all 8 events RCO goes first, FGC buffer indicating an overvoltage trigger (1st level)
RQD/F in S12 and S78
Total of 4 (yet unexplained) trips
NO Analysis still ongoing
RQT12.R4B1 Problem with output stage of power supply
DONE Trip due to a failure of PC. TRG OUTPUT STAGE POWER SUPPLY
RB.A34 / MB.A24R3 Heater Power supply discharging
DONE Problem appeared on Saturday but repair postponed to Sunday
RQX/RTQX2.L5 Temperature sensor problem
YES, but not fixed? Sensor DXEX02_03L5_TT891A faulty, no repair but only ‘touching’ cables
RB.A78 Broken micro-switch after opening of EE
YES Opening of switches to accelerate current decay after loss of CRYO
RQX R8, L8 and L1 Tripped when going from stand-by to OFF
NO Known ‘feature’, could maybe be solved through procedure by EPC
RQTD/F Tune correction currently limited by lower QPS thresholds >= 50A
QPS firmware / YES
Superimposition with B2 correction; proposal to increase 50A -> 75A
• Few additional issues discovered and solved by interventions done during the week
• Dominating issue is still with unexplained RQD/F trips in S12 and S78
[email protected] Interlock Systems
RCO.A56B2 /RCD.A56B2• RCO.A56B2 (and consequently RCD.A56B2) tripped another 3 times during the
week, total of 8 trips now in the past 2 weeks• Power supply module of RCO.A56B2 to be exchanged (indicating a trigger
through over voltage (1st level) -> Thursday?
Summary of the RQD/F events so far
Event time Sector
Circuit current
PIC history Switch timestamps
Other QPS buffers
30/03 at 08h49m45s
S81 Ramp with beam @1900A
RQF AND RQD @ 08.49.45.949
RQF @ 947RQD @ 947
DQAGMD @ 08.49.46.404DQAGMD @ 08.49.46.499
30/03 at 08h51m17s
S12 Ramp with beam @2100A
RQF @ 08.51.17.735RQD @ 08.51.17.736
RQF @ 731RQD @ 731
01/04 at 05h05m03s
S12 Flat top with beam @ 5300A
RQF @ 05.05.03.176RQD @ 05.05.03.178 by GPM
RQF @ 173RQD @ 173
01/04 at 08h43m06s
S12 Injection, no beam @ 750A
RQF AND RQD @ 08.43.06.141
RQF @ 137RQD @ 137
02/04 at 18h49m13s
S12 Standby, no beam @ 350A
RQF AND RQD @ 18.49.11.362
RQF @ 357RQD @ 358
04/04 at 02h49m48s
S78 Flat top with beam @ 5300A
RQF @ 02.49.48.756RQD @ 02.49.48.757
RQF @ 754RQD @ 753
DQAGMD @ 02.49.49.290DQAGMD @ 02.49.49.290
• During past days 4 yet unexplained trips on RQD/F circuits of sectors 12 and 78 were observed as shown in the summary below (completed by the two trips on Tue 30th of March due to the SPS main power supply)
All 4 events have an (almost identical) event sequence, ie● PIC receives a Quench/FastPA signal from QPS (event sequence in PIC is
the typical signature of an event originating within QPS)● RQD/F trip simultaneously (but for 1 event where the GPM is ‘faster’
than the RQD quench signal)● RQD and RQF switches open simultaneously and typically 3-5 ms
BEFORE the PIC records the quench signal, ie confirming that the QPS quench loop is broken (common QPS quench loop for RQD/F circuits!)
● No indication of changes in Discharge Request Loop, thus trip must be internal to QPS (no other means of opening the switches from outside)
● No other QPS PM buffers (apart from global busbar for 2 events and nQPS buffers which are well after the initial trip and a result of switch OFF of circuits) – Trip of 2nd QPS board?
‘Typical’ event sequence
The RQD/F.A12 ‘hump’
● Available data and event sequence seem to indicate triggers to origin within the QPS system, reason after loads of analysis however still unclear
● In sector 12 (where we had 3 oo 4 trips), busbar detector is showing repetitive noise patterns, some peaks up to 1.1V/550ms
● Further investigation with help of QPS experts needed as to the real origin of the trips…
