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Entry  Tue Jul 17 12:55:45 2018, Koji, Summary, General, Started pumping 6x
    Reply  Tue Jul 17 18:16:38 2018, Steve, Summary, VAC, pumpdown 81 at 6 hrs 6x
       Reply  Tue Jul 17 22:25:41 2018, Koji, Summary, VAC, pumpdown 81 at 6 hrs 
          Reply  Wed Jul 18 12:49:08 2018, Steve, Summary, VAC, pumpdown 81 at 6 +4.5hrs manlGateScan.pnghanding_over_Mag.pngTGVw2auxfans_.jpg
             Reply  Wed Jul 18 17:36:50 2018, Steve, Summary, VAC, pumpdown 81 at 6 +9 hrs completed pd81completed.pngpd81@30hrs.png
                Reply  Thu Jul 19 01:56:25 2018, gautam, Summary, VAC, AUX pump shutdown 
                   Reply  Thu Jul 19 11:01:03 2018, Steve, Summary, VAC, pd81 @ 2e-5 Torr pd81@2days.png
                      Reply  Thu Jul 19 13:35:30 2018, Steve, Summary, VAC, annuloses pumped  AnsPumped.png
                         Reply  Mon Jul 23 09:58:52 2018, Steve, Summary, VAC, RGA scan at day 6 pd81-560Hz-d6.png
                            Reply  Mon Aug 6 09:34:02 2018, Steve, Update, VAC, RGA scan at day 20 pd81d20.png
                               Reply  Thu Aug 16 07:50:28 2018, Steve, Update, VAC, pumpdown 81 at day 30 pd81d30.png
                                  Reply  Thu Aug 16 14:48:14 2018, Steve, Update, VAC, why do we need a root pump? 6x
                                     Reply  Fri Nov 16 10:26:12 2018, Steve, Update, VAC, single viton O-rings Single-O-ring.png
                                  Reply  Fri Aug 24 10:51:23 2018, Steve, Update, VAC, pumpdown 81 at day 38 d38.png
                                     Reply  Thu Oct 4 08:25:50 2018, Steve, Update, VAC, rga scan pd81 at day 78 pd81d78.png
                                        Reply  Fri Oct 12 08:27:05 2018, Steve, Update, VAC, drypump forepump.png
                                           Reply  Fri Oct 12 17:37:03 2018, Steve, Update, VAC, pressure gauge choices  
                                           Reply  Mon Oct 15 13:59:42 2018, Steve, Update, VAC, drypump replaced drypump_swap.png
                                        Reply  Tue Nov 13 16:15:01 2018, Steve, Update, VAC, rga scan pd81 at day 119 pd81-d119.pngpd81-560Hz-d119.png
Message ID: 14256     Entry time: Mon Oct 15 13:59:42 2018     In reply to: 14244
Author: Steve 
Type: Update 
Category: VAC 
Subject: drypump replaced 

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 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.


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