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The current specification
• EDMS 90327 from 2004 (LHC-PM-ES-0001 rev. 2.0)
• Refers to equipment tests from manufacturing to installation in LHC– Operation conditions
define the lower voltage– Apply decreasing voltages
through manufacturing
• Only single circuits vs. ground are considered
The voltage to ground for each circuit
• Two different sources of voltage during operation– Energy extraction at
maximum current U=RI– Quench voltage from
simulations
• Either/or for all circuits but for dipoles
• Safety factor 1.2 applied– Except for dipole circuit
• Missing RCO2xV+500Imax x REE
1.2xV
From ElQA EDMS 788197 (2008)
Test Voltage Test Test Voltage Test Test Voltage Test
voltage ramp duration voltage ramp duration voltage ramp duration
rate rate rate
[V] [V/s] [s] [V] [V/s] [s] [V] [V/s] [s]
Main Dipoles (MB) 600 2 300 600 2 300 1900 2 300
Main Quadrupoles (MQ) 120 5 300 120 5 300 240 5 300
Spoolpieces
(MCS, MCD)
Arc correctors (MSCB,MO) 300 10 180 300 10 180 600 10 180
Trim Quads
(MQT, MQTL, MQS)
Matching MQM
(1.9K)
Matching MQM
(4.5K)
Matching MQY 60 10 180 60 10 180 120 10 180
LowBeta Quads 210 5 300 210 5 300 420 5 300
Separator magnets 300 10 180 300 10 180 600 10 180
TP4-B TP4-D TP4-E
CIRCUIT type
240
180
240
240
480
360
480
240
180
240
480240
10 300
10 180
10 180
10 180
10 300
10 180
10
10 300
10 180
10 180180
10 180 10 180
Insulation tests during TP4-e tests
• Different classification from EDMS 90327
• Different tests for air cooled leads1. each circuit tested at a
lower voltage one by one versus all other circuits and ground.
2. all circuits of one chimney are tested together at higher voltage level vs ground.
RQ vs Spools
• M1/M2 lines and M lines run along together
• General protection will run down all of them at the same time
Line N circuits
• Bus-bar run together along the same cryogenic line
• Metallic braids already gave insulation problems
• MQT, MQTL, MQS, MSCB with energy extraction
• MO, MQM with no EE
Monday Morning Meeting : 3rd of May 2010
A. Perin AT-ACR, 8
Spool busbar routing inside DFBAs
Busbars in lines M1 & M2
Busbars merged with line N
All 600 A busbars in the same duct
CorrectorsSpool
Bundles of n x 4 busbars
New voltage to ground values
• Which electrical circuits have bus-bars running in the same cryo-line?
• Only circuits whose voltage is coming from EE should be taken into account.
• Nested circuits• Maximum operation
voltage x1.2
• Maximum operational voltage against any neighboring circuit
• Tested circuit vs. all others + ground
Voltage level proposal
• HV tests with new voltages need to be implemented prior to cool-down in 2011/2012
• RCO/RCB Lemo connector insulation weakness– Will be inspected in the next technical stop– Repair during the Xmas break?
• Tests of the two bus-bars of RQ?– Implemented during the assembly in the long
shutdown in 2012– Is it possible to interrupt the circuit?
Practical considerations
• Magnet instrumentation check– Local measurement at warm and cold– Continuity and resistance of diagnostic
Vtaps– Resistance and insulation of QH– QH against coil & ground
• ElQA test procedure needs to be updated– Can be done at the same time as HV
qualification for the magnet
MIC tests introduced during 2009
Quench heaters vs. ground
• Not specified in the note
• Minimum 2x450+500 = 1400 for most circuits
• Voltage on the coil during quench added to this value
• Not taken into account in US magnets during manufacturing
• Needs to be reviewed
• Tests in SM18 at cold • Reception tests in b181(at warm) for US
magnets• Minimum voltage retained• QH/coil vs. ground values?
MIC proposed HV values
• ElQA test procedure 788197 to be rewritten and reissued
• Higher values to be applied almost in all correctors RQ(M) and RQ circuits
• MIC test to be added• Hardware modifications in DFB
chimneys to remove limitations to be implemented– During Xmas stop– During long shutdown
Conclusions
• Machine will be emptied • Three days cooling tower cleaning
will stop active cooling on DFBs• All DFBs SAM and SC links will warm
up above 120K• According to A. Perin that will mean
a full thermal cycle• What parts of ElQA need to be
redone?
Xmas break ElQA tests