Changed to series mode.

Got a call at about 10:00 this morning, the whole system had tripped off. 
No power bumps or other disturbances. When I arrived the only fault 
indications were "ColdBox Trip" light on the compressor panel and on the 
QRL panel the red "ColdBox" LED was ON. On the SULZER panel the 
yellow "Cryostat Quench" light was ON. On the First Trip logger #1 and #15 
LED's were ON. But no indication about what the actual fault was. Cooling 
water OK, compressed air OK, compressor ventilation OK. Outside ambient 
temperature was cooler than we had last week. BIG1 was off but when I 
turned it back on the vacuum looked good but was slowly rising as the 
solenoid warmed. I put the jumper on the vacuum controller. Prepared system 
for re-start.

Started compressor. Started flow thru coldbox. Raised discharge pressure.
Started turbine flow. Didn't get any freezing but it seemed that T1 speed 
wandered slowly +/-0.1k rev/sec when it got up to about 3.6k revs/sec, but 
this only lasted for a second or two. Not sure if I was just seeing things.
Got turbines up to speed and started // warm return flow. Solenoid had been 
running at 500 Amps and when it quenched and sat warming it had warmed to 
about 40 K. Switched it to //cold return too soon and solenoid started to 
warm slightly. Back to // warm return mode. Had to throttle flow thru 
solenoid with warm return valves to get effective cooling. If had return 
valves wide open TI121 would warm up too much. Discovered that if I 
throttle the flow out of the solenoid slightly then TI121 would fall and 
solenoid would start to cool. Less flow gave more cooling. Don't quite 
understand that one. Switched to // cold return mode when solenoid temps 
falling below 20K.

About 15:00 stable // cold return cooling. Going home for a while.

19:30 solenoid temps bottomed out at about 11K. Switch to series mode. 
Something strange about the first trip detect. I reset it once and when I 
checked it an hour or two later it showed a trip on #1 and #15 LED's even 
though nothing had happened. Something must be causing false indications.

20:15 series cooling, solenoid temps at about 6K, LHe level rising slowly 
at about 10%. Removed jumper on vacuum controller.

23:39 Powerleads cold, LHe level over 40% and rising. Energizing solenoid 
to 500 Amps, ramp rate 60. Checking compressor building then going home.

Solenoid had tripped on powerlead overtemp at about 09:00 this morning. 
Doug recovered the system to // cooling. I switched system to series 
cooling at about 21:30. LHe level at about 10%. Buffer tank pressure is low 
at about 13 psig. Letting LHe level build. Once LHe level rises to about 
35% then I suggest starting flow to the powerleads by opening HIC142 fully 
open. LHe level should continue to build but at a much slower rate. Once 
power lead temps have bottomed out to cr_pl_neg < 9K and cr_pl_pos < 11 K 
(check these values with archived data first) and are stable then can 
energize solenoid.

started flow to the power leads at 11:30. Cold and stable at 1:00am. 
Energized solenoid at 1:30.

Solenoid quenched Nov 21 due to alarge power bump. Everything tripped off 
including vacuum and water pumps. Cold box vacuum was at 3.6e-1, so pumped 
it out overnight.
Started compressor at 7:20. Started turbines at 7:40.

Started flow to solenoid in parallel warm return.

Compressor tripped off again due to a power bump. Meson hall water off, so 
vacuum pumps off again.
Pumps back on , vacuum pumps on, starting compressor.

Came in this morning to find the helium return line to the buffer tank 
frosted up. MV51 has been stuck open the whole time. That exlains the 
cooldown rate and other problem. Cycled MV51 a few times and it now seems 
closed. Switched back to parallel cold return this moring at 8:00. Rates 
are much better. The E-log was also down this morning.

Curtis switched to series mode last night at 7:00.
Startedflow to power leads at 7:00 this morning.

Got page very early this morning. Couldn't come in til 08:30. System was 
in idle running mode and someone had reset the QRL panel so my guess is 
that the solenoid tripped on powerlead overtemp. HIC142 was not fully open 
and I suspect this is why powerleads heated up. Now in // cold return mode.
Solenoid temps down to 25K and slowly going down. Have HIC142 slightly open 
to keep powerleads cool. Strongly recommend that when running HIC142 should 
be fully open to try to reduce the probability of powerlead warmup.

I recieved a call from ops at 22:00 tonight that the solenoid had alarmed. 
I came in and found a cold box fault, with the compressor tripped off. I 
was unable to restart the compressor. I cleared the cryostat quench and 
compressor trips. The system looked as though it was ready to start. I 
pushed the compressor "ON" button, but as soon as the main contactor 
closed, the compressor tripped again. After a few trys and a bit of 
searching, I tried resetting the compressor over-pressure switch. That 
allowed me to restart the compressor. Once the high pressure comes up I'll 
start flow to the turbines.

See attached file for a screen grab of temps.

This is a strip tool  plot of the cooldown

See screen grab

The compressor was restarted and the solenoid is cooling (sort of) in 
parallel cold return.

From about 08:00 to 15:00

See Doug's previous entry for quench recovery details.
First the system had been set to // cold return mode because the solenoid 
temps seemed low enough. Temps started to rise instead of cooling so system 
was eventually set back to // warm return mode. With the system in // warm 
return mode the solenoid was still warming instead of cooling. Solenoid 
temps were rising to almost 50K and T1 shield heater was about 90%. T1 
inlet temp was below 75K and falling even with shield heat set so high. 
CV155 kept closed and // warm return flows were full flow. T1 brake valve 
seemed way too open at about 0.8 (compared to previous runs).

15:00 to 19:00

Tried opening CV155, didn't seem to help much. Temps still trending 
upwards. Decided to reduce flow to solenoid to see if the cold box would 
cool down. Started reducing the // warm return outlet valves. TI121 began 
to drop slowly. On graph plotting solenoid temps they started to trend 
downwards. Weird. A reduced flow seemed to produce more cooling ? Don't 
understand this but will continue. Flow temps returning from solenoid were 
about the same temp as TI121, about 35 K. Switching to // cold return mode 
to try to reduce TI121. Keeping CV155 as open as possible, just keeping 
CV204 from closing completely. After switching to // cold return TI121 
starts to slowly fall, T1 inlet temp rises over time so start to drop 
shield heater setting. Solenoid temps now trending downwards. Cracked open 
CV142 to get some flow going through powerleads. Raised compressor 
discharge press to about 11.2 barA. Shield heater down over time to about 
10%. Reduced CV155 down to the point where temps almost stop falling then 
open cv155 just enogh to keep temps falling.

19:30 Solenoid temps down to about 28K. Letting system continue cooling 
overnight.

Guessing the cause of the turbine overspeed quench was caused by 
contamination entering the spinning turbine, causing rapid speed changes or 
possibly the continued saga of the water damaged Jaquet turbine speed 
tachometer giving random false trips.

see bitmap for temps/pressures after presurrizing coldbox. Preparing to 
start flow to turbines, then will start flow to solenoid in parallel warm 
return.