LPI Moscow, K. Zhukov, MEPhI-LPI Moscow, V. Kantserov TRT HV System status LPI Moscow, K. Zhukov, MEPhI-LPI Moscow, V. Kantserov 28 oct 2013 K. Zhukov, LPI Moscow

outline HV problems in 2012-13 What’s happened + repairing HV maintenance + firmware (HV SYS, Dubna) Plans for TRT HV in Nov-Dec 2013 28 oct 2013 K. Zhukov, LPI Moscow

HV problems in 2012-13 It caused shortcut in UPS line which was tripped. 460V pins shortage -> burned February 2012. Crate 003 & 004 (EC A) PS dropped. Bottom crate in Barrel rack dropped twice during 10 days -> the same damages on diode: dust on the PS board surface? December 2012. Bottom crate in barrel dropped two times during 10 days. In June V. Astakhov covered boards’ surfaces with HV lacquer. Crates were tested with load and assembled. But in September appeared the crate was burned at 460V pins. September 2013. Crate 007 in SR1 dropped. The crate was covered with lacquer in June but has broken. All misbehaved cells were successfully changed Few small problems with individual cells. 28 oct 2013 K. Zhukov, LPI Moscow

What’s happened (crate 007) 460 V pins: remains of shortcut. The part of conductor was burned. In June crate was checked and covered with HV lacquer by V. Astakhov. In September we tried to switch on it appeared it’s broken. It was shortcut between 460 V pins (as it was in crate 003). PFC was seriously damaged and sent to Dubna for recovery and investigation. Crate is in SR1 disassembled. It’s waiting for repair. 28 oct 2013 K. Zhukov, LPI Moscow

What’s happened (crate 010) After some investigations we assumed that it was some outside factor (e.g. dust) on surface which caused the shortcut in HV diode pins. It lead to high current in the branch of diode-bridge -> PS dropped We had to change two pairs of DIODE-MOSFET, 16&10 A fuses, PFC board. All surfaces were covered with URETHAN protective lacquer. 28 oct 2013 K. Zhukov, LPI Moscow

What’s happened (crates 003&004) What was damaged After repairing Valera Astakhov analyzed the PFC board damages and it seemed there was some defect in capacitors -> he found electrolyte remains on the boards – it lead to 460V pins shortage. We had to change two pairs of DIODE-MOSFET, 16&10 A fuses, PFC board and part of conductor. All surfaces were covered with URETHAN protective lacquer.

2013 maintenance activity In June 2013 maintenance for all HV crates was done by Valera Astakhov from HVSYS. All crates are checked and now (except one) ready to use in USA15 and SR1 areas. What was done: Review of all crates and its power supplies All crates’ power supply have been disassembled and covered with Electrofuge 200-ND (protective lacquer) All PFC boards were checked. Old version boards changed by upgraded ones PS3500 assembling and testing under 900W load was done (equivalent to ~1 mA/ch) Thermal inspection of components (during working on 900W load without cooling) was done All crates were assembled and its functionality was checked. All 8 crates have good state of its parts. Upgraded PFCs stay in all PS3500s. Few HV cells were replaced. One crate is repairing… waiting for PFCs from Dubna. 28 oct 2013 K. Zhukov, LPI Moscow

HV crates review, June ’13 All power supplies were disassembled and boards were covered with protection Electrofuge 200-ND to prevent dust shortages on pins. 28 oct 2013 K. Zhukov, LPI Moscow

HV crates test 900W load Thermal picture of power supply boards (left) and radiator of the crate without external cooling at output load 900W (without cooling). All temperatures on PS boards are in working ranges. No overheating observed. 28 oct 2013 K. Zhukov, LPI Moscow

HV SC508 Firmware upgrade In September 2013 Vitaly Shutov was at CERN and made the firmware upgrade for SC508 to work at higher baud rate. Jolanta made tests and it seemed it works well. See DCS talk for more details. 28 oct 2013 K. Zhukov, LPI Moscow

Plans for TRT HV in Nov-Dec 2013 Installing filters in rack cooling to prevent dust in air flow. It was decided to install some grids to prevent metallic debris falling on PS surfaces. Calibration checks for all HV channels (Kantserov V., Vasilyeva L.) from mid- of November. + capacity test(?) Cleaning racks in USA15, connecting cables to TRT. Investigation of over/under shoots events. That’s now a question how to simulate all things correctly… (e.g. is it enough RC-equivalent of cables, other things) 28 oct 2013 K. Zhukov, LPI Moscow

Thank you very much! 28 oct 2013 K. Zhukov, LPI Moscow