Meeting, 25 September 2012

(meeting at Building 30-4-45 with Dominique Bodart, Konstantinos Papastergiou)

We discussed the magnets of TT2 line.

The issue of BHZ377 inductance discrepancy

After the inspection made by DB the magnets have been found all according to the NORMA DB. There are some different labels such as HB3r or HB3l which refer to variations of the same magnet type but the exact details are not known. In fact the discrepancy between measured values by KP (and other EPC colleagues in the past) and Norma inductance values cannot be explained by just looking at the magnet nameplate. The best information you have (and can trust) is your own measurements.

KP we will issue a document containing our measurements and we will use these for the converter design then. Could we do the following:

• update NORMA with a comment about our measurements (reference to document EDMS #1242402)

• during the shutdown LS1 you could perform a measurement in place to confirm our measured values

DB sure we can do this.

ACTION: update NORMA database (to handled by DB)

Consolidation Plans

KP what is included in your consolidation project?

DB we will replace some magnets starting with the Quadrupoles.

KP do you expect a change in inductance and resistance values?

DB no you should not notice a difference as the exact same magnet type will be used (tolerances around 1%).

Field measurements in magnets

KP There is an issue with cycling some of the magnets which take too long to reset their field. For instance the BHZ377 takes nearly 1.6second to degaus and introduces delays to operation. There two potential solutions:

• to increase the voltage using a higher voltage converter. In this case a statement is needed from the magnets that this is OK.
• to completely scrap the degaussing cycle in case we can measure the magnetic field through the air gap and use this as feedback to the converter.

The second solution is also a long term solution as it addresses energy saving issues (a degaussing cycle consumes considerable amounts of reactive power).

DB this is a very interesting aspect. There are some solutions like the one used in the PS with a reference magnet that has a magnet field probe in the airgap. In this case though there is physically not space for a probe so other solutions may be needed (such as using a printed circuit board that could be placed right on the magnet poles. If KP could send an email with the exact requirements DB could discuss with colleagues.

ACTION: KP shall send an email with typical converter cycles, description of the problem and request.

end of the meeting.

Set ALLOWTOPICVIEW = TT2ConsolidationGroup

-- KonstantinosPapastergiou - 25-Sep-2012