RP1 and RP3 roughing pump manual of Leybold D30A oily rotory pump
Fore pump of TP2 & TP3 Varian SH-100 Dry Scroll
TP2 and TP3 small turbo drag pump Varian 969-9361
TP2 and TP3 turbo controller Varian 969-9505
TP1 magnetically suspended turbo pump Osaka TG390MCAB, sn360 and controller TC010M and note : this pump running on 208VAC single phaseIt is not on the UPS !
Osaka Maglev Manual and Osaka Controller Communication Wiring
VC1 cryo pump CTI-Cryogenics Cryo Torr 8 sn 8g23925 SAFETY note: compressor single phase 208VAC and the head driver 3 phase 208VAC Compressor and driver have each separate power cord!
Installed at 40m wiki also
The V1 gate valve specs installed at 40m wiki page. VAT model number 10846-UE44-0007 Our main volume pumping goes through this 8" id gate valve V1 to Maglev turbo or Cryo pump to VC1
The ion pumps have 6" id gate valves:VAT 10844-UE44-AAY1, Pneumatic actuator with position indicator and double acting solenoid valve 115V 60Hz Purchased 1999 Dec 22
UHV gate valves 2.5" id. VAT 10836-UE44 Pneumatic actuator with position indicator and double acting solenoid valve 115V 60 hz, IFO to RGA VM1 & RGA to Maglev VM2
mini UHV gate valve 1.5" id. VAT 01032-UE01 2016 cataloge page 14, manual - no position indicator, VM4 next to manual adjustable fine leak valve to RGA
UHV angle valve 1.5" id, model VAT 28432-GE41, Viton plate seal, pneumatic actuator with position indicator & solenoid valve 115V & single acting closing spring MEDM screen: VM3,VC2, V3,V4,V5,V6,VA6,V7 & annuloses Each chamber annulos has 2 valves.
UHV angle valve 1.5" id, model VAT 57132-GE05 go page 208, Metal tip seal, manual actuating only with position indicator, MEDM screen: roughing RV1 and venting VV1 hand wheel needed to close to torque spec
UHV angle valve 1.5" id. model VAT 28432-GE01 Viton plate seal, manual operation only at IT gauges Hornet & Super Bee and ion pumps roughing ports. These are not labeled.
The Cryo pump interlock wiring was added too
Note: all moving valve plate seals are single.
Valve configuration: Vacuum normal
Note: Tp2 running at 75Krpm 0.25A 26C has a load high pitch sound today. It's fore line pressure 78 mTorr. Room temp 20C
IFO pressure 1.2e-5 Torr at 9:30am
Atm. 1, This was the vacuum condition this morning.
IFO P1 9.7 mTorr, V1 open, V4 was in closed position , ~37 C warm Maglev at normal 560Hz rotation speed with foreline pressure 3.9 Torr because V4 closed 2 days ago when TP2 failed .....see Atm.3
The error messege at TP2 controller was: fault overtemp.
I did the following to restored IFO pumping: stopped pumping of the annulose with TP3 and valves were configured so TP3 can be the forepump of the Maglev.
closed VM1 to protect the RGA, close PSL shutter .....see Gautam entry
aux fan on to cool down Maglev-TP1, room temp 20 C,
aux drypump turned on and opend to TP3 foreline to gain pumping speed,
closed PAN to isolate annulos pumping,
opened V7 to pump Maglev forline with TP3 running at 50Krpm, It took 10 minutes to reach P2 1mTorr from 3.9 Torr
aux drypump closed off at P2 1 mTorr, TP3 foreline pressure 362 mTorr.......see Atm.2
As we are running now:
IFO pressure 7e-6 Torr at Hornet cold cathode gauge at 15:50 We have no IFO CC1 logging now. Annuloses are in 3-5 mTorr range are not pumped.
TP3 as foreline pump of TP1 at 50 Krpm, 0.24 A, 24 C, it's drypump forline pressure 324 mTorr
V4 valve cable is disconnected.
I need help with wiring up the logging of the Hornet cold cathode gauge.
Our new Agilent Technology TwisTorr 84FS AG rack controller ( English Manual pages 195-297 ) RS232/485, product number X3508-64001, sn IT1737C383
This controller, turbo and it's drypump needs to be set up into our existing vacuum system. The intake valve of this turbo (V4) has to have a hardwired interlock that closes V4 when rotation speed is less than 20% of preset RPM speed.
The unit has an analoge 10Vdc output that is proportional to rotation speed. This can be used with a comperator to direct the interlock or there may be set software option in the controller to close the valve if the turbo slows down more than 20%
The last Upgrade of the 40m Vacuum System 1/2/2000 discribes our vauum system LIGO-T000054-00-R
Here the LabView / Metrabus controls were replaced by VME processor and an Epic interface
We do not have schematics of the hardware wiring.
We need help with this.
PSL shutter closed at 6e-6 Torr-it
The foreline pressure of the drypump is 850 mTorr at 8,446 hrs of seal life
V1 will be closed for ~20 minutes for drypump replacement..........
9:30am dry pump replaced, PSL shutter opened at 7.7E-6 Torr-it
Valve configuration: vacuum normal as TP3 is the forepump of the Maglev & annuloses are not pumped.
TP3 drypump replaced at 655 mTorr, no load, tp3 0.3A
This seal lasted only for 33 days at 123,840 hrs
The replacement is performing well: TP3 foreline pressure is 55 mTorr, no load, tp3 0.15A at 15 min [ 13.1 mTorr at d5 ]
Valve configuration: Vacuum Normal, ITcc 8.5E-6 Torr
Dry pump of TP3 replaced after 9.5 months of operation.[ 45 mTorr d3 ]
The annulosses are pumped.
Valve configuration: vac normal, IFO pressure 4.5E-5 Torr [1.6E-5 Torr d3 ] on new ITcc gauge, RGA is not installed yet.
Note how fast the pressure is dropping when the vent is short.
IFO pressure 1.7E-4 Torr on new not logged cold cathode gauge. P1 <7E-4 Torr
Valve configuration: vac.normal with anunulossess closed off.
TP3 was turned off with a failing drypump. It will be replaced tomorrow.
All time stamps are blank on the MEDM screens.
The TP3 foreline pressure was 4.8 Torr, 50K rpm 0.54A and 31C........Maglev rotation normal 560 Hz....... IFO pressure 7.2e- 6 Torrit was not effected
V1 closed ......replaced drypump.........V1 opened
IFO 6.9e-6 Torrit at 19:55, TP3fl 18 mT, 50Krpm 0.15A 24C
VM1 is still closed
Annuloses are not pumped for 30 days, since TP2 failed. IFO pressure 7e-6 Torr it, Rga 2.6e-6 Torr
Valve configuration: Vacuum Normal as TP3 is the forepump of Maglev, annuloses are not puped at 1.1 Torr
TP3 50K rpm, 0.15A 24C, foreline pressure 16.1 mTorr
There was a power outage.
The IFO pressure is 12.8 mTorr-it and it is not pumped. V1 is still closed. TP1 is not running. The Rga is not powered.
The PSL output shutter is still closed. 2W Innolight turned on and manual beam block placed in its beampath.
3 AC units turned on at room temp 84F
IFO pumped down from 44 mTorr to 9.6e-6 Torr with Maglev backed with only TP3
Aux drypump was helping our std drypump during this 1 hour period. TP3 reached 32 C and slowed down 47K rpm
The peak foreline pressure at P2 was ~3 Torr
Hornet cold cathode gauge setting: research mode, air,
2830 HV 1e-4A at 9.6e-6 Torr,
[ 3110 HV 8e-5A at 7.4e-6 Torr one day later ]
Annuloses are at 2 Torr, not pumped
Valve configuration: vacuum normal, RGA is still off
PSL shutter is opened automatically. Manual block removed.
End IR lasers and doublers are turned on.
NOTE: Maglev " rotation X " on vacuum medm screen is not working! " C1:Vac-TP1_rot " channel was removed. Use " NORMAL X " for rotation monitoring.
*We removed this (i.e. rotation) field from the MEDM screen to avoid confusion.
pd80b rga scan at 175 day. IFO pressure 7.3e-6 Torr-it
Condition: vacuum normal, annuloses not pumped. Rga turned on yesterday.
The rga was not on since last poweroutage Jan 2, 2018 It is warming up and outgassing Atm2
Hornet cold cathode gauge analoge output [ DSub9 pin 3 and 7 ] are wired to go ETMX Acromag. It was reading 4.9V at 7.8e-6 Torr [ 3,110 V 8.35e-5A ] at the end of a 24ft BNC cable. Now it has to be hook up to an Acromag channel.
This will replace the not functioning C1: Vac-CC1_pressure
gautam: the motivation behind hooking this gauge up to our DAQ system is that non-vacuum-system-experts have a quick diagnostic to make sure everything is in order. This gauge is physically placed adjacent to V1, and so if something goes wrong with our vacuum pumps, we would see the effect here immediately. we did note that occassionally, the reading fluctuated by ~1V on the DMM used to check the voltage output at the end of the BNC cable, so we still need to run some long-term stability analysis once this channel is hooked up to the Acromag. For future reference, in order to make this gauge work, we need to check that
The forline pressure of TP3 was 399 mTorr
It was replaced this morning at TP3 controller 134,638hrs with the "failed TP2 station" drypump. The foreline pressure now at TP3 is 100 mTorr at 6 hrs of operation.[ at day 3 63 mT ]
IFO pressure at CC Hornet 7.9e - 6 Torr
Valve configuration: vacuum normal as TP3 is the forepump of the Maglev & the annuloses are not pumped
I wired the six available BNC connectors on the front panel of the new XEND slow DAQ to physical Acromag channels. There were two unused ADC channels and eight DAC channels, of which I connected four. The following entries were added to /cvs/cds/caltech/target/c1auxex2/ETMXAUX2.db /caltech/target/c1auxex2/ETMXaux2.db
C1:Vac-CC1_HORNET_PRESSURE_VOLT is converted to the additional soft channel C1:Vac-CC1_HORNET_PRESSURE in units of torr using the conversion stated in the manual. A quick check showed that the resulting number and the displayed pressure on the vacuum gauge itself agree to ~1e-8 torr. Gautam added the new EPICS calc channel to the C0EDCU and restarted FB, now the data is being recorded.
Three of the output channels do not have a purpose yet, so their epics records were created but remain inactive for the time being.
We have the IFO pressure logged again! Thanks Johannes and Gautam
This InstruTech cold cathode ionization vacuum gauge " Hornet " was installed 2016 Sep 14
Here is the CC1 gauge history of 10 years from 2015 Dec 1
The next thing to do is put this channel C1:Vac-CC1_HORNET_PRESSURE on the 40m Vacuum System Monitor [ COVAC_MONITOR.adl ]
gautam 1pm: Vac MEDM screen monitor has been edited to change the readback channel for the CC1 pressure field - see Attachment #2. Seems to work okay.
In Steve's absence, I've tried to keep an eye on the health of the vacuum system. From Attachment #1, the pressure of the main volume seems stable, no red flags there. I also don't here any anomalously loud sounds near the vacuum pumps. I've changed the N2 cylinders that keep V1 open twice, on Wednesday and Sunday of last week. So in summary, the vacuum system looks fine based on all the metrics I know of.
Pumpdown 80 at 511 days and pd80b at 218 days
Valve configuration: special vacuum normal, annuloses are not pumped at 3 Torr, IFO pressure 7.4e-6 Torr at vac envelope temp 22 +- 1C degrees
CC1 old MKS cold cathode gauge randomly turns on- off. This makes software interlock close VM1 to protect RGA So the closed off RGA region pressure goes up and the result is distorted RGA scan.
CC1 MKS gauge is disconnected and VM1 opened. This reminds me that we should connect our interlocks to CC1 Hornet Pressure gauge.
Valve configuration: special vacuum normal, annuloses are not pumped at 3 Torr, IFO pressure 7.4e-6 Torr at vac envelope temp 22 +- 1C degrres
We added the following channels to C0EDCU.ini and restarted the daqd processes. Channels seem to have been added successfully, we will check trend writing later today. Motivation is to have a long term record of annulus pressure (even though we are not currently pumping on the annulus).
plot next day
We are getting ready to vent.
Steve gave me a venting tutorial. I'll record this in probably a bit more detail than is strictly necessary, so I can keep track of some of the minor details for future reference.
Here is Steve's checklist:
Gautam already did the pre-vent checks, and Steve took a screenshot of the IFO alignment, IMC alignment, master op lev screen, suspension condition, and shutter status to get a reference point. We later added the TT_CONTROL screen. Steve turned off all op levs.
We then went inside to do the mechanical checks
After completing these checks, we grabbed a nitrogen cylinder and hooked it up to the VV1 filter. Steve gave me a rundown of how the vacuum system works. For my own memory, the oil pumps which provide the first level of roughing backstream below 500mtorr, so we typically turn on the turbo pumps (TP) below that level... just in case there is a calibrated leak to keep the pressure above 350mtorr at the oil pumps. TP2 has broken, so during this vent we'll install a manual valve so we can narrow the aperture that TP1 sees at V1 so we can hand off to the turbo at 500mtorr without overwhelming it. When the turbos have the pressure low enough, we open the mag lev pump. Close V1 if things screw up to protect the IFO. This 6" id manual gatevalve will allow us throttle the load on the small turbo while the maglev is taking over the pumping The missmatch in pumping speed is 390/70 l/s [ maglev/varian D70 ] We need to close down the conductive intake of the TP1 with manual gate valve so the 6x smaller turbo does not get overloaded...
We checked CC1, which read 7.2utorr.
Open the medm c0/ce/VacControl_BAK.adl to control the valves.
Steve tells me we are starting from vacuum normal state, but that some things are broken so it doesn't exactly match the state as described. In particular, VA6 is 'moving' because it has been disconnected and permanently closed to avoid pumping on the annulus. During this v ent, we will also keep pumping on the RGA since it is a short vent; steve logged the RGA yesterday.
We began the vent by following the vacuum normal to chamber open procedure.
Everything looks good, so I'm monitoring the vent and swapping out cylinders.
At 12:08pm, the pressure was at 257 torr and I swapped out in a new cylinder.
Steve: Do not overpressurize the vacuum envelope! Stop around 720 Torr and let lab air do the rest. Our bellows are thin walled for seismic isolation.
Steve and Aaron,
6 hrs vent is reaching equlibrium to room air. It took 3 and a half instrument grade air cilynders [ AI UZ300 as labelled ] at 10 psi pressure. Average vent speed ~ 2 Torr/min
Valve configuration: IFO at atm and RGA is pumped through VM2 by TP1 maglev.
- Attachment1: Removed the thermal cap. Checked the temperature of the oven. It was totally cold.
- Attachment2: Confirmed the RGA section was isolated. The pumps for the RGA was left running.
- Attachment3: Closed the main valve. The pumps for the main volume was left running.
- Attachment4: Started removing the rid. This did not change the gause readings as they were isolated from the venting main volume.
- Attachment5: Opened the rid. Took the components out on a UHV foil bag. The rid was replaced but loosely held by a few screws with the old gasket, just to protect the frange and the volume from rough dusts.
We are in the process of adding a manual gate valve between TP1 (Osaka Maglev) and the other gate valves (I suppose V1 and VM2).
The work is still on going and we will continue to work on this tomorrow. Because this section is isolated from the main volume, this work does not hold off the possible rough pumping tomorrow morning.
The motivation of this work is as follows:
- Since TP2 failed, the main vacuum volume has been pumped down by TP1 and TP3. However TP3 is not capable to handle the large pressure difference at the early stage of the turbo pumping. This cause TP3 to have excessive heating or even thermal shutdown.
- The remedy is to put a gate valve between TPs and the main vacuum to limit the amount of gas flowing into the TPs. This indeed slows down the pumping speed of turbo, but this is not the dominant part of the pumping time.
- Comfirmed TP1 is isolated.
- Unscrewed the flange of TP1.
- Remove TP1. This required to lift up TP1 with some shim as the nuts interferes with the TP1 body. (Attachment1, 2, 3)
- Now remove 10inch flange adapter. (Attachment4)
-Attach 10"-8" adapter and 8" rotational sleeve. (Attachment5)
Precondition: 4 days at atm. Atm5
HEPA tent used during the vent at ETMY It reduced partical count 10 fold of 0.5 and 0.3 micron particals. Atm6
New items in vacuum: Clean manual gate valve [Cetec made] from John Worden with 6" id....as it came from Hanford... [ Throttle able gate valve- TGV ] Atm3
( note: we have 3 more identical in the lab. The original intention was to use them for purging gates )
Optiform Au plated reflector , Induceramics heating elements, similar as existing Cooner cables and related lenses, hardwear. see 14078
OMC related item : none......... 14,110
The pumpdown is at 510 mTorr with RP1 & RP3 still pumping. Koji will shut it down the roughing later tonight. Tomorrow morning I will start the pumping by switching over to TP1 maglev.
Thanks for Koji and Gautam' help of the installation of the manual gate valve. Atm4 This will allow us to control the load on our Varian foreline D70 turbo TP3
The P1 pressure is 380mTorr. I allowed Gautam to use the full PSL power (~1W).
The manual gate valve scan was clean. Atm1 TP1 was pumping on it overnight.
Pumpdown continued to hand over the pumping to TP1 maglev turbo
V1 was opened at P1 400 mTorr with manual gate at 3/4 turn open position as Magev at 560 Hz rotation.
Two aux fans on to hold tubo temps TP1 & TP3 . Atm3
This is the first time we pumping down from atm with ONE small "beer can" turbo and throttled gate valve to control load on small turbo forepump
The 70 l/s turbo is operating at 50k RPM, 0.7 A and 31 C, pumping speed ~ 44 mTorr/h at 200-400 mTorr range with aux drypump in the foreline of TP3
Watching foreline pressures and current one can keep opening gate valve little by little the so the load is optimized. It is working but not fast.
Let's keep small turbo at 0.8 Amp and 32 C max at this pumpdown.
IFO P1 6e-4 Torr, manual gate valve is fully open
The annuloses will be pumped down tomorrow.
Valve configuration: vacuum normal, RGA and annuloses are not pumped
This is the first time we pumping down from atm with one small "beer can" turbo and throttled gate to control load on small turbo forepump
The 70 l/s turbo is operating at 50k RPM, 0.7 A and 31 C, pumping speed ~ 44 mTorr/h at 200-400 mTorr range.
Per Steve's instructions, we did the following:
Cold cathode gauge just turned on.
Roughing down the annuloses required closing V1 for 13 minutes
IFO is 2.2e-5 Torr
The manufacturer of a vacuum pump supplies a chart for each pump showing pumping speed (volume in unit time) vs pressure. The example, for a fictitious pump, shows the pumping speed is substantially constant over a large pressure range.
By multiplying pumping speed by pressure at which that pumping speed occurs, we get a measure called pump throughput. We can tabulate those results, as shown in the table below, or plot them as a graph of pressure vs pump throughput. As is clear from the chart, pump throughput (which might also be called mass flow) decreases proportionally with PRESSURE, at least over the pressure range where pumping speed is constant.
The roughing pump speed actually will reach 0 l/s at it's ultimate pressure performance.
Our roughing pump pumping speed will slowly drop as chamber pressure drops. Below 10 Torr this decrease is accelerated and bottoms out. This where the Root pump can help. See NASA evaluation of dry rough pumps...What is a root pump
We have been operating succsessfully with a narrow margin. The danger is that the Maglev forline peaks at 4 Torr. This puts load on the small turbo TP2, TP3 & large TP1
The temperature of these TP2 & 3 70 l/s drag turbos go up to 38 C and their rotation speed slow to 45K rpm from 50K rpm because of the large volume 33,000 liters
Either high temp or low rotation speed of drag turbo or long time of overloading can shut down the small turbo pumps......meaning: stop pumping, wait till they cool down
The manual gate valve installed helped to lower peak temp to 32C It just took too long.
We have been running with 2 external fans [one on TP1 & one on TP3] for cooling and one aux drypump to help lowering the foreline pressure of TP2 & 3
The vacuum control upgrade should include adding root pump into the zero pumping speed range.
Atm1, Pump speed chart: TP1 turbo -red, root pump -blue and mechanical pump green. Note green color here representing an oily rotory pump. Our small drypumps [SH-100] typically run above 100 mTorr
They are the forepump of TP2 & 3 Our pumpdown procedure: Oily Leybold rotory pumps ( with safety orifice 350 mT to atm ) rough to 500 mTorr
Here we switch over to TP2 & 3 running at 50k RPM with drypumps SH-100 plus Aux Triscroll
TP1- Maglev rotating full speed when V1 is opened at full volume at 500 mTorr
History: the original design of the early 1990s had no dry scroll pumps. Oil free dry scrools replaced the oily forepumps of TP2 & TP3 in ~2002 at the cost of degrading the forline pressure somewhat.
We had 2 temperature related Maglev failers in 2005 Aug 8 and 2006 April 5 Osaka advised us to use AUX fan to cool TP1 This helped.
Atm2, Wanted Root pump - Leybold EcoDry 65 plus
Atm3, Typical 8 hrs pumpdown from 2007 with TP2 & 3
Atm4, Last pumpdown zoomed in from 400 mT to 1mT with throttled gate valve took 9 hrs The foreline pressure of TP1 peaked at 290 mT, TP3 temperature peaked at 32C
This technic is workable, but 9 hrs is too long.
Atm5, The lowest pressure achived in the 40m Vacuum Envelope 5e-7 Torr with pumps Maglev ~300 l/s, Cryo 1500 l/s and 3 ion pumps of 500 l/s [ in April 2002 at pumpdown 53 day 7 ] with annuloses at ~ 10 mTorr
Atm6, Osaka TG390MCAB Throughput with screen ~300 L/s at 12 cfm backing pump
TP-1 Osaka maglev controller [ model TCO10M, ser V3F04J07 ] needs maintenance. Alarm led on indicating that we need Lv2 service.
The turbo and the controller are in good working order.
Our maintenance level 2 service price is $...... It consists of a complete disassembly of the controller for internal cleaning of all ICB’s, replacement of all main board capacitors, replacement of all internal cooling units, ROM battery replacement, re-assembly, and mandatory final testing to make sure it meets our factory specifications. Turnaround time is approximately 3 weeks.
RMA 5686 has been assigned to Caltech’s returning TC010M controller. Attached please find our RMA forms. Complete and return them to us via email, along with your PO, prior to shipping the cont
Osaka Vacuum USA, Inc.
510-770-0100 x 109
our TP-1 TG390MCAB is 9 years old. What is the life expectancy of this turbo?
The Osaka maglev turbopumps are designed with a 100,000 hours(or ~ 10 operating years) life span but as you know most of our end-users are
running their Osaka maglev turbopumps in excess of 10+, 15+ years continuously. The 100,000 hours design value is based upon the AL material being rotated at
the given speed. But the design fudge factor have somehow elongated the practical life span.
We should have the cost of new maglev & controller in next year budget. I put the quote into the wiki.
Steve pointed out that some of the vacuum MEDM screen fields were reporting "NO COMM". Koji confirmed that this is a c1vac1 problem, likely the same as reported here and can be fixed using the same procedure.
However, Steve is worried that the interlock won't kick in in case of a vacuum emergency, so we are leaving the PSL shutter closed over the weekend. The problem will be revisited on Monday.
Following the procedure in this elog, we effected a reset of the vacuum slow machines. Usually, I just turn the key on these crates to do a power cycle, but Steve pointed out that for the vacuum machines, we should only push the "reset" button.
While TP1 was spun down, we took the opportunity to replace the TP1 controller with a spare unit the company has sent us for use while our unit is sent to them for maintenance. The procedure was in principle simple (I only list the additional ones, for the various valve closures, see the slow machine reset procedure elog):
However, we were foiled by a Philips screw on the DB37 connector labelled "MAG BRG", which had all its head worn out. We had to make a cut in this screw using a saw blade, and use a "-" screwdriver to get this troublesome screw out. Steve suspects this is a metric gauge screw, and will request the company to send us a new one, we will replace it when re-installing the maintaiend controller.
Attachments #1 and #2 show the Vacuum MEDM screen before and after the reboot respectively - evidently, the fields that were reading "NO COMM" now read numbers. Attachment #3 shows the main volume pressure during this work.
The problem will be revisited on Monday.
Precondition: c1vac1 & c1vac2 all LED warning lights green [ atm3 ], the only error message is in the gauge readings NO COMM, dataviewer will plot zero [ atm1 ], valves are operational
When our vacuum gauges read " NO COMM " than our INTERLOCKS do NOT communicate either.
So V1 gate valve and PSL output shutter can not be triggered to close if the the IFO pressure goes up.
[ only CC1_HORNET_PRESSURE reading is working in this condition because it goes to a different compuer ]
Gautam and Steve,
Our TP3 drypump seal is at 360 mT [0.25A load on small turbo] after one year. We tried to swap in old spare drypump with new tip seal. It was blowing it's fuse, so we could not do it.
Noisy aux drypump turned on and opened to TP3 foreline [ two drypumps are in the foreline now ] The pressure is 48 mT and 0.17A load on small turbo.
We want to measure the pressure gradient in the 40m IFO
Our old MKS cold cathodes are out of order. The existing working gauge at the pumpspool is InstruTech CCM501
The plan is to purchase 3 new gauges for ETMY, BS and MC2 location.
Basic cold cathode or Bayard-Alpert Pirani
Steve & Bob,
Bob removed the head cover from the housing to inspect the condition of the the tip seal. The tip seal was fine but the viton cover seal had a bad hump. This misaligned the tip seal and it did not allow it to rotate.
It was repositioned an carefully tithened. It worked. It's starting current transiant measured 28 A and operational mode 3.5 A
This load is normal with an old pump. See the brand new DIP7 drypump as spare was 25 A at start and 3.1 A in operational mode. It is amazing how much punishment a slow blow ceramic 10A fuse can take [ 0215010.HXP ]
In the future one should measure the current pick up [ transient <100ms ] after the the seal change with Fluke 330 Series Current Clamp
It was swapped in and the foreline pressure dropped to 24 mTorr after 4 hours. It is very good. TP3 rotational drive current 0.15 A at 50K rpm 24C
Gautam & Steve,
Our controller is back with Osaka maintenace completed. We swapped it in this morning.
Steve reported to me that the CC1 Hornet gauge was not reporting the IFO pressure after some cable tracing at EX. I found that the power to the unit had been accidentally disconnected. I re-connected the power and manually turned on the HV on the CC gauge (perhaps this can be automated in the new vacuum paradigm). IFO pressure of 8e-6 torr is being reported now.
Jon and I stuck a extender card into the eurocrate at 1X8 earlier today (~5pm PT), to see if the box was getting +24V DC from the Sorensen or not. Upon sticking the card in, the FAIL LEDs on all the VME cards came on. We immediately removed the extender card. Without any intervention from us, after ~1 minute, the FAIL LEDs went off again. Judging by the main volume pressure (Attachment #1) and the Vacuum MEDM screen (Attachment #2), this did not create any issues and the c1vac1 computer is still responsive.
But Steve can perhaps run a check in the AM to confirm that this activity didn't break anything.
Is there a reason why extender cards shouldn't be stuck into eurocrates?
The vacuum and MC are OK