2. , RACK POWER SUPPLY AND CONTROL as proposed by ST-EL. J. Pedersen, ST-EL Presentation,J.C.O.B., 05.06.2002 1

3. , SUMMARY  Introduction  Power equipment u ALICE and LHC-B. u ATLAS and CMS.  Control possibilities  Cost  Conclusion 2

4. , INTRODUCTION  The aim: u ST-EL provides a state of the art power supply with adequate monitoring. u The experiments can control the power distribution to their racks. u The experiments can define trip conditions for the racks through an “External interlock” u The experiments can view the status of the power distribution of the racks 3

5. , POWER DISTRIBUTION EQUIPMENT  ALICE and LHC-B. u Recuperate existing HAZEMEYER switchboards. u Relatively voluminous, cabling through false floor.  ATLAS and CMS. u Use new “CANALIS” style distribution equipment. u An isolated bus-bar system. Very dense construction, thus well suited for installation in areas of limited space. u Routed in steel housing, thus very low field emissions. 4

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8. , POWER AVAILABILITY  Basic assumption: The racks will be fed from the normal supply, i.e. neither diesel nor UPS back up.  If a short-break supply ( diesel back-up ) or a no-break supply ( UPS with or without diesel back-up is required, this will come with a price tag attached to it.  The experiments should analyse their needs for back-up carefully. 7

9. , RACK POWER EQUIPMENT  Try to avoid single phase switch mode power supplies with simple capacitive input stages. u This type of equipment means heavy 3rd harmonic pollution of the power network. It requires de-rating of the power equipment and may require filtering: Increased cost  If possible, use three phase or single phase equipment with sinusoidal input current and a power factor close to 1. 8

10. , CONTROL POSSIBILITIES  The control interface equipment between ST-EL and the experiments will be based on a PLC solution.  The experiment will be able to command the individual feeders ON/OFF. ST-EL will not retain a command possibility.  The experiment will be able to monitor the status of each feeder  The experiment will be able to use an external interlock ( A 48 V, potential free contact, normally closed, open on fault ) 9

11. , COST  Cost is incurred by:  Re-vamping of the HAZEMEYER equipment  Purchase of CANALIS-type equipment  Installation and cabling*) work  HOW MUCH WILL IT COST?  I DO NOT KNOW !  ANYWAY, YOU WILL HAVE TO PAY FOR IT  *) ALICE and LHC B mainly 10

12. , POTENTIAL PROBLEMS  Will the equipment work properly in high magnetic fields?  Field emission by the power distribution; This is seen as a possible problem by certain people in ATLAS. ST-EL believes that a bus-bar system as described here, can alleviate these fears. 11

13. , CONCLUSION  ST-EL can supply a powering system for the experimental electronics racks that seem to fulfil the requirements of the experiments.  ST-EL will have to: u Establish an overview of existing HAZEMEYER equipment and cost the re-vamping of it. u Launch a call for tenders for “CANALIS” like equipment u Estimate installation costs  To allow ST-EL to do this in a sensefull way the experiments will have to define their needs, including needs for safe power! 12