Subject: recent shutdown

From: Mark Klaene

Submitted: Mon, 19 May 2003 09:39:37 -0600

Message number: 671 (previous: 670, next: 672 up: Index)

This past week the observatory used 5 days and nights primarily to 
work on the shutter drive assemblies. This work was a carry over from 
last summer when the drive boxes were replaced. At that time 1 of the 
new boxes developed a leak and it turned out while these were exact 
duplicates of the originals, they were improperly specified for our 
application back in the 1980s. Consequently the only solution was to 
have new units designed for our application installed. The following 
is a short summary of the engineering activities of the week.

The enclosure shutter drive repairs were completed for both the left 
and right shutter.  The refurbished and modified drives that were 
installed are not leaking like the one installed last summer.  We 
found that drive to be nearly empty of lubricant as feared.  The 
double seals on the downward facing shaft flanges should prevent the 
failure mode we experienced with the original drives and the 1 new 
drive. Other improvement are properly placed refill plugs, modified 
inner seal, and low temp oil.  Doors open and close smoothly.  Motor 
currents look nominal. No work on the wheels, bearings, or rails  was 
accomplished but some work is still planned for the June engineering 
time.

Dome exterior paint touched-up since we had the lift handy from the 
shutter work

Grim evacuated and cooled.

Dis red camera noise was improved significantly by the grounding of 
the power supply returns.



-- 

Mark Klaene
Observatory Engineer, Deputy Site Manager		voice: 505 437 6822
Apache Point Observatory				fax:   505 434 5555
PO box 59
2001 Apache Point Rd
Sunspot NM 88349

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