THOMAS JEFFERSON NATIONAL ACCELERATOR FACILITY
ACCELERATOR OPERATIONS CREW CHIEF SIGN IN FORM
Date : 01-05-23
Time : 07:12:10
Day : Thursday
Shift : Day
Crew Chief : Humphry
Program Deputy: Spata
Team : X
Arm : RadCon
Designated SSO: Christian
Operators : Christian
This stamp certifies that the above Crew Chief has read/reviewed/received the following:
EGG took a look at it on swing shift and gave the okay to adjust alarm limits, ~21:00.
GMES has been going up and down ever since. Slightly adjusted the LOLO to keep it from alarming.
Fig 3&4: Looks like it could be related to phase fluctuations.
Mark and I ran repaired ARC3 power supply on a resistive load (2.33 Ohms) today up to 450A. Looking at the diagnostic waveform on NSH side @ 300A and 450A we see that the current sharing among all four NSH4 sections aren't equal rather NSH3 is running around 10% higher than rest of them. Please note NSH3 converter section is where we replaced the bad choke last year.
Tomorrow we will look into the PWM board because if the reference triangular voltage is higher then it will drive the IGBT harder and run higher current depending on the percentage off.