Sequence of QC steps for main bus bar splices

Sequence of QC steps for main bus bar splices

Control of cables and stabiliser prior to connection by ICIT team

Temperature control during soldering, visual inspection of the finished splice by operators

QC visual and geometric inspection according to IEG-C-BR-001 rev C

QC US test

In case of doubts (e.g. previous NCRs on cable or bus bar stabiliser) Gamma ray

Splice resistance measurement should be developed to become a standard QC tool

C. Scheuerlein, 7.4.2009

Example QC of QBBI.B25R3

• Produced the 17.3.2009. Special U-piece (-1 mm length) used for M3-corridor. OK

• Visual and geometric inspection by QC team according to IEG-C-BR-001 rev C, the 18.3.2009. OK

• US-test 4 out of 4 US signals OK for all splices.• Splice thickness OK.• NCR 993939 was opened and gamma ray

examination was requested for QBBI.B25R3-M3-cryoline, because room temperature splice resistance of 12.4 μΩ is higher than average values.


Resistance results QBBI.B25R3-M3-cryoline

• The higher resistance is at the lyra side of QBBI.B25R3-M3-cryoline (7.60.1 μΩ and 5.90.2 μΩ for lyra and connection side, respectively (distance between voltage taps=8.5 cm)).

• Resistance result is influenced by position of voltage taps (e.g. 11.90.5 μΩ and 12.6 0.2 μΩ for measurements on top or on the side of splice, respectively (distance between voltage taps=17 cm)).


Photos QBBI.B25R3-M3-cryoline

top view bottom viewside view

QBBI.B25R3-M3-cryoline

QBBI.B25R3-M3-cryoline-lyra-side (R= 7.60.1 μΩ)


Gamma rays QBBI.B25R3-M3

QBBI-B25R3-M3Cor-cC

QBBI-B25R3-M3-Cor-connectionQBBI-B25R3-M3-Cor-lyra

QBBI-B25R3-M3-QRL-connection QBBI-B25R3-M3QRL-lyra (7.60.1 μΩ)


US test result QBBI.B25R3-M3-cryoline

• For all splices tested so far during the 2009 shutdown we found 4 out of 4 good US signals.


Temperature cycle QBBI.B25R3-M3-cryoline


0

50

100

150

200

250

300

15:28:48 15:36:00 15:43:12 15:50:24 15:57:36

Tem

pera

ture

(°)

QBBI.B25R3-M3-cryoline17.3.2009

QQBI.29R3-M1-corridor• NCR 993937, splice resistance above average values.• The cable and bus bar stabiliser of SSS 221 were damaged in

SMA18.• Visual and geometrical control result is acceptable.• Because of the stabiliser deformation prior to soldering, a perfect

splice could not be achieved. Therefore, we asked for resistance measurement and gamma ray images.

• Splice resistance is with 19.2 μΩ somewhat higher than average values.

QQBI.29R3-M1-corridor


QQBI.29R3-M1 gamma ray images

QQBI-29R3-M1-Cor-CoQQBI-29R3-M1-Cor-Ly

QQBI-29R3-M1-QRL-Co QQBI-29R3-M1-QRL-Ly


NCRs for QBBI.A32R3

• NCR 994206 for M3-cryoline gap with an approximate macroscopic transverse cross section of 20 mm2. Splice resistance measured by TE-MPE team =10.7 μΩ, which is not significantly higher than average.

• NCR 993950 for M1-cryoline because of comparatively high splice resistance (20.3 μΩ).

• Resistance of M2-corridor=19.6 μΩ (always with a distance of 17 cm between voltage taps).


Photos QBBI.A32R3• Visual and geometric inspection by QC team according

to IEG-C-BR-001 rev C. M1 and M2 OK

QBBI.A32R3_M1 QBBI.A32R3_M2

QBBI.A32R3_M1

QBBI.A32R3_M1


QBBI.A32R3 resistance results• QBBI.A32R3-M1-cryoline

– Total 19.70.3 μΩ (over 17 cm)– connection side-10.0 0.1 μΩ (8.5 cm)– lyra side-12.7 0.4 μΩ (8.5 cm)

• QBBI.A32R3-M2-cryoline– Total 21.30.1 μΩ (over 17 cm)– connection side-12.00.5 μΩ (8.5 cm)– lyra side-10.80.2 μΩ (8.5 cm)

• Influence of the voltage tap position on M1 and M2 splices (e.g. QBBI.A32R3-M2-corridor resistance =21.30.1 μΩ and 20.60.6 μΩ as measured with voltage taps at the side and on top of the splice, respectively).


Gamma rays QBBI.A32R3

QBBI-A32R3-M1QRL-cC 10.0 0.1 μΩ

QBBI-A32R3-M1QRL-cL 12.7 0.4 μΩ

QBBI-A32R3-M2QRL-cC QBBI-A32R3-M2QRL-cL

Splice resistance measurement as QC tool

• The room temperature splice resistance measurement is the only functional quality control that can be performed in-situ. Resistance measurements from TE-MPE team have demonstrated that comparative splice resistance values can be obtained.

• Visual inspection can only detect macroscopic gaps on the outside of the splice.

• Therefore, a comparative splice resistance measurement should be performed on all splices. A procedure should be defined so that we all measure in the same way.

• We need threshold values for acceptable and not acceptable resistance values for M1 and M3 splices, taking into account the limitations of the resistance measurement set-up (short distance between current source and voltage taps).


Example NCR 993403 concerning splice thickness

• NCR LHC-MSC-QBBI.A27R3-sur M1 coté corridor, coté gauche, epaisseur plus importante qu'habituellement de la connexion.

• A second cycle was performed without disconecting the splice. Thickness was reduced from 11.4 mm to 10.9 mm. Room temperature splice resistance 17.6 μΩaverage value. X-rays taken. NCR closed with warning.

QBBI.A27R3-M1-corridor-lyra QBBI.A27R3-M1-corridor-connection

X-ray images taken after 2nd cycle

QBBI.A27R3-M1-corridor-lyra


Quality control of line N and line M US welds

• Visual and geometrical inspection according to standard procedures IEG-C-US-001 RevC “Controle visuel des soudures US sur les bus bars auxiliaires des lignes M1 et M2” and IEG-C-US-002 “Controle visuel des soudures US de type N”.

• On-line analysis of production data (weld duration) by operators (not an acceptance criterion).

• Production data is saved on dfs.

• Photos of all US welds are saved on dfs.


Qualification of US welding and inductive soldering machines

• US4, US5 and US6 qualified for line N spool welds (round strand) with 0.80 mm compression (enfoncement).

• US1, US2, US3, US7 qualified for line M spool welds (rectangular strand) with 0.68 mm compression.

• BR2, BR3, BR5, BR7 qaulified for main bus bar soldering.

• Qualification results can be found under:\\cern.ch\dfs\Workspaces\s\Sector81Interconnect\Shutdown2009\Quality-Control\Electrical-Connections\Rc-results-tensile-tests


Sequence of QC steps for main bus bar splices

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