Instrument Rail Vibration Measurement

  • Data collected 02 May, 2010 using OVMS and Labview quicklook software

  • Treehouse fans on/off. (15-Hz when on)

  • Power was cut to all four treehouse fans for test. Follow-up testing will consider affects of individual treehouse fans.

  • DX secondary was not installed on the LBT. (It was in the clean-room.)

  • DZ tertiary accelerometers not installed (2 installed, but not connected. 3 not installed.)

  • HBS active with stow-pins installed

  • Accelerometer locations on rails:
    instrument_rail_accelerometer_placement.jpg

Notes on plots

  • Turning the treehouse fans on does not result in a single-frequency contribution to the overall vibration power
    • Measurements form the rails show that some "steps" (peaks in the PSD plot, steps in the cumulative sum plot) are made larger by the treehouse fan activation
    • Surprisingly, there is not a strong peak near 15-Hz, where the fans are operating. There is action between 30-Hz and 50-Hz-- likely excitation by the treehouse ventilation

  • The 55-Hz action is there, as usual. Note that it is virtually independent of the treehouse fan settings and HBS status

  • Not much action from 60-Hz to 500-Hz. (Therefore plots have been truncated to 100-Hz.)

  • Vibration normal to the instrument rails is made slightly larger ( O(10)-nm ) with activation of HBS system. Additional contribution seems to be at lower frequency (<10-Hz typical) with some amplification over existing peaks/steps.

  • Vibration at SX M2 is made smaller ( O(100)-nm ) with activation of HBS system

Displacement Spectral Density Comparisons (Instrument Rails)

  • compare.zip: Instrument rail PSD comparison plots
    • Note two sets of data were collected for each condition. Only the first set is illustrated on the this page. Both sets of plots are included in this zip file.

  • SX rear instrument rail:
    SX_rail_rear_00.jpg

  • SX center instrument rail:
    SX_rail_center_00.jpg

  • DX rear instrument rail:
    DX_rail_rear_00.jpg

  • DX center instrument rail:
    DX_rail_center_00.jpg

-- JorgeEsguerra - 08 Jun 2010

Displacement Spectral Density Comparisons (SX Secondary Mirror)

  • SX M2 Accelerometer 1:
    SX_M2_1_00.jpg

  • SX M2 Accelerometer 2:
    SX_M2_2_00.jpg

  • SX M2 Accelerometer 3:
    SX_M2_3_00.jpg

  • SX M2 Accelerometer 4:
    SX_M2_4_00.jpg

  • SX M2 Accelerometer 5:
    SX_M2_5_00.jpg

-- JorgeEsguerra - 08 Jun 2010

Displacement Spectral Density (SX Tertiary Mirror)

  • SX M3 Accelerometer 1:
    SX_M3_1_00.jpg

  • SX M3 Accelerometer 2:
    SX_M3_2_00.jpg

  • SX M3 Accelerometer 3:
    SX_M3_3_00.jpg

  • SX M3 Accelerometer 4:
    SX_M3_4_00.jpg

  • SX M3 Accelerometer 5:
    SX_M3_5_00.jpg

-- JorgeEsguerra - 08 Jun 2010

Displacement Spectral Density (Individual plots)

DX (Right) Instrument Rail - Center Position

  • DX center, HBS off, THV off:
    Pxx_DX_center_hbs_off_thv_off_00.jpg

  • DX center, HBS off, THV on:
    Pxx_DX_center_hbs_off_thv_on_00.jpg

  • DX center, HBS on, THV off:
    Pxx_DX_center_hbs_on_thv_off_00.jpg

  • DX center, HBS on, THV on:
    Pxx_DX_center_hbs_on_thv_on_00.jpg

DX (Right) Instrument Rail - Rear Position

  • DX rear, HBS off, THV off:
    Pxx_DX_rear_hbs_off_thv_off_00.jpg

  • DX rear, HBS off, THV on:
    Pxx_DX_rear_hbs_off_thv_on_00.jpg

  • DX rear, HBS on, THV off:
    Pxx_DX_rear_hbs_on_thv_off_00.jpg

  • DX rear, HBS off, THV on:
    Pxx_DX_rear_hbs_on_thv_on_00.jpg

SX (Left) Instrument Rail - Center Position

  • SX center, HBS off, THV off:
    Pxx_SX_center_hbs_off_thv_off_00.jpg

  • SX center, HBS off, THV on:
    Pxx_SX_center_hbs_off_thv_on_00.jpg

  • SX center, HBS on, THV off:
    Pxx_SX_center_hbs_on_thv_off_00.jpg

  • SX center, HBS on, THV on:
    Pxx_SX_center_hbs_on_thv_on_00.jpg

SX (Left) Instrument Rail - Rear Position

  • SX rear, HBS off, THV off:
    Pxx_SX_rear_hbs_off_thv_off_00.jpg

  • SX rear, HBS off, THV on:
    Pxx_SX_rear_hbs_off_thv_on_00.jpg

  • SX rear, HBS on, THV off:
    Pxx_SX_rear_hbs_on_thv_off_00.jpg

  • SX rear, HBS on, THV on:
    Pxx_SX_rear_hbs_on_thv_on_00.jpg

-- JorgeEsguerra - 04 Jun 2010
I Attachment Action Size Date Who Comment
DX_rail_center_00.jpgjpg DX_rail_center_00.jpg manage 235 K 08 Jun 2010 - 17:22 UnknownUser DX center instrument rail
DX_rail_rear_00.jpgjpg DX_rail_rear_00.jpg manage 235 K 08 Jun 2010 - 17:21 UnknownUser DX rear instrument rail
M2_M3_data.zipzip M2_M3_data.zip manage 3 MB 08 Jun 2010 - 17:17 UnknownUser SX Secondary and SX Tertiary PSD comparison plots
Pxx_DX_center_hbs_off_thv_off_00.jpgjpg Pxx_DX_center_hbs_off_thv_off_00.jpg manage 115 K 07 Jun 2010 - 16:56 UnknownUser DX center, HBS off, THV off
Pxx_DX_center_hbs_off_thv_on_00.jpgjpg Pxx_DX_center_hbs_off_thv_on_00.jpg manage 117 K 07 Jun 2010 - 16:56 UnknownUser DX center, HBS off, THV on
Pxx_DX_center_hbs_on_thv_off_00.jpgjpg Pxx_DX_center_hbs_on_thv_off_00.jpg manage 116 K 07 Jun 2010 - 16:57 UnknownUser DX center, HBS on, THV off
Pxx_DX_center_hbs_on_thv_on_00.jpgjpg Pxx_DX_center_hbs_on_thv_on_00.jpg manage 115 K 07 Jun 2010 - 16:59 UnknownUser DX center, HBS on, THV on
Pxx_DX_rear_hbs_off_thv_off_00.jpgjpg Pxx_DX_rear_hbs_off_thv_off_00.jpg manage 115 K 07 Jun 2010 - 17:00 UnknownUser DX rear, HBS off, THV off
Pxx_DX_rear_hbs_off_thv_on_00.jpgjpg Pxx_DX_rear_hbs_off_thv_on_00.jpg manage 117 K 07 Jun 2010 - 17:00 UnknownUser DX rear, HBS off, THV on
Pxx_DX_rear_hbs_on_thv_off_00.jpgjpg Pxx_DX_rear_hbs_on_thv_off_00.jpg manage 115 K 07 Jun 2010 - 17:01 UnknownUser DX rear, HBS on, THV off
Pxx_DX_rear_hbs_on_thv_on_00.jpgjpg Pxx_DX_rear_hbs_on_thv_on_00.jpg manage 117 K 07 Jun 2010 - 17:02 UnknownUser DX rear, HBS off, THV on
Pxx_SX_center_hbs_off_thv_off_00.jpgjpg Pxx_SX_center_hbs_off_thv_off_00.jpg manage 115 K 07 Jun 2010 - 17:12 UnknownUser SX center, HBS off, THV off
Pxx_SX_center_hbs_off_thv_on_00.jpgjpg Pxx_SX_center_hbs_off_thv_on_00.jpg manage 116 K 07 Jun 2010 - 17:12 UnknownUser SX center, HBS off, THV on
Pxx_SX_center_hbs_on_thv_off_00.jpgjpg Pxx_SX_center_hbs_on_thv_off_00.jpg manage 114 K 07 Jun 2010 - 17:13 UnknownUser SX center, HBS on, THV off
Pxx_SX_center_hbs_on_thv_on_00.jpgjpg Pxx_SX_center_hbs_on_thv_on_00.jpg manage 116 K 07 Jun 2010 - 17:13 UnknownUser SX center, HBS on, THV on
Pxx_SX_rear_hbs_off_thv_off_00.jpgjpg Pxx_SX_rear_hbs_off_thv_off_00.jpg manage 114 K 07 Jun 2010 - 17:14 UnknownUser SX rear, HBS off, THV off
Pxx_SX_rear_hbs_off_thv_on_00.jpgjpg Pxx_SX_rear_hbs_off_thv_on_00.jpg manage 119 K 07 Jun 2010 - 17:15 UnknownUser SX rear, HBS off, THV on
Pxx_SX_rear_hbs_on_thv_off_00.jpgjpg Pxx_SX_rear_hbs_on_thv_off_00.jpg manage 114 K 07 Jun 2010 - 17:15 UnknownUser SX rear, HBS on, THV off
Pxx_SX_rear_hbs_on_thv_on_00.jpgjpg Pxx_SX_rear_hbs_on_thv_on_00.jpg manage 115 K 07 Jun 2010 - 17:16 UnknownUser SX rear, HBS on, THV on
SX_M2_1_00.jpgjpg SX_M2_1_00.jpg manage 226 K 08 Jun 2010 - 16:13 UnknownUser SX M2 Accelerometer 1
SX_M2_2_00.jpgjpg SX_M2_2_00.jpg manage 218 K 08 Jun 2010 - 16:13 UnknownUser SX M2 Accelerometer 2
SX_M2_3_00.jpgjpg SX_M2_3_00.jpg manage 235 K 08 Jun 2010 - 16:13 UnknownUser SX M2 Accelerometer 3
SX_M2_4_00.jpgjpg SX_M2_4_00.jpg manage 228 K 08 Jun 2010 - 16:14 UnknownUser SX M2 Accelerometer 4
SX_M2_5_00.jpgjpg SX_M2_5_00.jpg manage 228 K 08 Jun 2010 - 16:14 UnknownUser SX M2 Accelerometer 5
SX_M3_1_00.jpgjpg SX_M3_1_00.jpg manage 226 K 08 Jun 2010 - 16:16 UnknownUser SX M3 Accelerometer 1
SX_M3_2_00.jpgjpg SX_M3_2_00.jpg manage 236 K 08 Jun 2010 - 16:16 UnknownUser SX M3 Accelerometer 2
SX_M3_3_00.jpgjpg SX_M3_3_00.jpg manage 246 K 08 Jun 2010 - 16:17 UnknownUser SX M3 Accelerometer 3
SX_M3_4_00.jpgjpg SX_M3_4_00.jpg manage 219 K 08 Jun 2010 - 16:17 UnknownUser SX M3 Accelerometer 4
SX_M3_5_00.jpgjpg SX_M3_5_00.jpg manage 216 K 08 Jun 2010 - 16:18 UnknownUser SX M3 Accelerometer 5
SX_rail_center_00.jpgjpg SX_rail_center_00.jpg manage 225 K 08 Jun 2010 - 17:20 UnknownUser SX center instrument rail
SX_rail_rear_00.jpgjpg SX_rail_rear_00.jpg manage 219 K 08 Jun 2010 - 17:20 UnknownUser SX rear instrument rail
compare.zipzip compare.zip manage 3 MB 09 Jun 2010 - 00:03 UnknownUser Instrument rail PSD comparison plots
individual_tests.zipzip individual_tests.zip manage 3 MB 07 Jun 2010 - 17:21 UnknownUser Individual plots for 4 positions on instrument rails
instrument_rail_accelerometer_placement.jpgjpg instrument_rail_accelerometer_placement.jpg manage 136 K 08 Jun 2010 - 17:26 UnknownUser Accelerometer locations on rails
Topic revision: r4 - 09 Jun 2010, JorgeEsguerra
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