ACES SYSTEMS Cobra II, Руководство пользователя

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Gen II
User Manual
13-6 – Transient Vibration Survey Chapter 13 Revision 4.10, Apr 20
acceleration or deceleration of the engine (or component being checked) you may wish to
set the rate at longer intervals, 200 or 500 for instance.
13.1.1.1.9. Use the [

] key to move to the “ Define related tachs? ” field. This field will allow you
to define correlations between vibration channels and tach signals. The default field
value is “No” which correlates all vibration channels with all tach inputs. By selecting
“Yes”, using the [

] key, additional Tach selection fields will appear to the right of the
“Max” fields in the upper set of “Channel” definition rows. See paragraph 13.1.1.1.14
below for information about filling in additional fields that will appear as a result of your
selection.
13.1.1.1.10. Use the [

] key to move to the “ Units ” column of the “Channel A:” row. Select an
engineering unit from the available list by using [

] key. A selection of “None” in the
field indicates there will be no input to the Channel (A, B, C, or D) adjacent to the field
where the word “None” appears. Your selection determines the engineering units in
which the vibration spectra will be displayed. Each channel is independent of the other
three so that the type of unit can vary between channels. For example, you may select
IPS in channel A for velocity, g’s in channel B for acceleration, Mils in channel C for
displacement, and db in Channel D for acoustics. Any selection, other than “None” will
automatically provide additional selection fields in the “Mod”, “Max” and “Sensor”
columns.
13.1.1.1.11. Use the [

] key to move to the “ Mod ” field. The “Mod” field determines the modifier
that will be applied to the engineering units of the spectra. Consult your equipment
maintenance manual for specific requirements of a vibration survey or for analysis
guidelines. Use the [

] key to select the modifier, such as Peak, Peak-to-Peak (Pk-Pk or
DA, Double Amplification), RMS (Root Mean Square) or Average. Consult the
appropriate equipment maintenance manual for specific requirements of an overall
vibration survey or for analysis guidelines.
13.1.1.1.12. Move to the “ Max ” field using the [

] key. “Max” means the Maximum Amplitude
value, relative to the engineering units selected in paragraph 13.1.1.1.9 above, you expect
to see in this job. Use the [

] key to select a maximum value above, but not less than the
value you expect to see.
13.1.1.1.13. The “ BBnd ” (Broadband) check box can be enabled when the engine you are surveying
has a requirement to measure vibration over a different frequency range than the range
defined in paragraphs 13.1.1.1.2 through 13.1.1.1.4 above. This type of survey typically
applies to the Pratt & Whitney PT6, PW100 or PW200 series of engines, but other
engines may also be configured this way. Use the [

] key to select (display a dot in the
box) or deselect (remove a dot from the box) this feature. Enabling this feature will
provide additional configuration screens described in 13.1.1.6 below. There are several
unique properties related to the use of this feature. First, the vibration units for this
measurement will be displayed in the same units that are used for configuring the