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User name fansler
Log entry time 06:08:24 on November 17, 2007
Entry number 215004
keyword=LQ2 OVERTEMP FAULT
Left Q2 tripped on an overtemp fault. Fault would not reset remotely.
Vince entered the hall and reset the supply locally. The supply ramped
to 1200 amps and tripped on overtemp again. I entered the hall, checked
LCW flow it was normal. I installed external cooling (fans) and ramped
again, this time the magnet tripped at 1600 amps. I tried diferent fan
configuations but I was unable to overcome the heating problem with
external cooling at 1600 amps. The magnet power supply didnt seem to
have heating problems at lower currents so we may be able to run with
this fault at a lower momentums. The alternative is to call in a second
technician to safe the magnet to verify the thyrister bank is the faulty
component. The thyrister bank repair is approximately an eight hour
repair. While I was in the hall troubleshooting the left Q2, the right
dipole and right Q1 lost liquid level, and all the right arm lead flows
increased signifigantly. The Q1 recoverd and the leasd flows are back in
normal ranges. We are still waiting for the dipole to refill.
A copy of this log entry has been emailed to: fansler@jlab.org