Gregorian weight

mar10

 Weighing the dome using load cells and jacks.
Weight the dome using motor torques:
    jun13: after the hydraulic brake was installed
    25jun02:Weighing the dome using motor torques.
Summary

Intro

    The gregorian dome has been weighed using the following techniques:


Weighing the dome. dec98,feb03,oct05

    Below is jose Maldonado's 28mar03 dome weight memo:

The dome weight could be weighed by two different methods. These are
with jacks on each of the four corners  or with a load cell lifted
from the azimuth feed arm top. On the week of Feb  27,2003, the
dome was weighed; first, with the jack and then with the load cell, I
should mention that when the jack's method is used the trolleys are
excluded. In order to determine the trolley's weight, several elements
were weighed during the yoke replacement project and the rest of the
weight was calculated. The total weight  obtained for the trolleys
before the yokes modifications was 17,144 lbs. and after the yokes
modification 19,980 lbs.

    As of 2/27/03 (jose's memo had 12/02/98 but i think that was a typo) the dome weight
was 215,390.4 with jacks and 215,660 with load cells. The attached
addendum A-1 has a break down of Dome weight per corner and a summary of
weight obtained with different methods and different dates. The dome
was at 1.05 degrees all day long during the measurements.

    On 12/2/98 the dome weight with the jacks became 156,075 lbs. On 2/27/03 five (5) years later the weight from 12/2/98 to 2/27/03 is 59,315 lbs and the dome weight is 215,660 lbs.

Jose maldonado's oct05 dome weight memo (.pdf)


Weighing the dome with jacks and load cells
date
type
Measure
Notes
corner1
corner2
corner3
corner5
20051024
Corner
Weights
Jacks
without trolley weight
18458
uphill left
10521
uphill right
76932
downhill right
72691
downhill left

with trolley weight (4995/corner)
23453
15516
81927
77686



Uphill
Downhill

Uphill/
downhill
totals

38969.0
159613.

total

198582

2/27/03
Corner
Weights
Jacks
without trolley weight
18,768
19,872
79,488
77,280
with trolley weight (4995.6/corner) 23764
24868
84484
82276
load cell
includes trolley weight
34980
13060
85860
81760



Uphill
Downhill
Uphill/
downhill
totals
Jacks
48631
166759
load cell
48040
167620
Total
Jacks
215390
load cell
215660
  
12/02/98
Corner
Weights
Jacks
without trolley weight
16305
6581
62418
53628
with trolley weight (4286/corner)
20590
10867
55704
57914


Uphill
Downhill
Uphill/
downhill
totals

31457
124618
Total
156075









Notes:



Weighing the dome using the motor torques:

jun13: weight the dome using uphill motor torques (after the hydraulic brake)

    The hydraulic brake was installed in jun02 on the dome. Fits were done for torques moving uphill. One of the fit parameters was the dome weight.(dome weight)

25jun02: Weighing the dome using motor torques (before the hydraulic brake)

    On 25jun02 the dome was driven uphill and downhill at different velocities. The motor torques need to do this were recorded and then used to compute the dome weight. This was done before the hydraulic brake system was installed on the dome.
processing: x101/Y02/020621/doitgr.pro

Summary:


Date
Measurement
Dome Weight (including trolleys)
 (kips)
02dec98
Jacking the dome
156075
25jun02
Gregorian motor torques
208,000
27feb03
jacking the dome
215390
27feb03
load cells lifting the dome
215660


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