ACES SYSTEMS Cobra II, Руководство пользователя

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Gen II
User Manual
13-11 – Transient Vibration Survey Chapter 13 Revision 4.10, Apr 20
pulse frequency (Hz) of the tach source at 100%. The component speed (RPM) at 100%
is then divided by the tach pulse frequency to obtain the factor. In the example above, the
“N2” speed at 100% is 10,000 RPM and the tach pulse frequency is 4000 Hz. This will
give us a factor of “2.5”. If the tach pulse frequency is unknown, set the FACTOR to “1”
and read the value for the applicable tach channel at a known stable engine speed. The
indicated tach pulse frequency can then be divided into the known engine speed at that
point. For this purpose, it is recommended to use the analyzer’s “Monitor Overall”
function (see Chapter 19) as it is quicker and easier to configure.
13.1.1.4.5. When viewing Plots, you should know the minimum and maximum speeds of interest.
When you arrive at that speed range, use the keypad to enter the “
Plot Min ”, or minimum
speed of interest in this column.
13.1.1.4.6. For the “ Plot Max ” you should, likewise, determine the speed range of interest and enter
the maximum speed of that range in this column using the keypad.
13.1.1.4.7. The “ Plot Div ” determines the intervals or divisions of speed indication on the plots
across the full speed range. For instance, if you intend to view the plot in a range of 1000
to 2000 RPM and wish it to be in divisions of 500 RPM, enter “2” in this column using
the keypad. That is, the upper range (2000) minus the lower range (1000) divided by
increments of 500 RPM = 2 divisions. The valid range for the field is 0 to 10. An entry of
1 will show NO incremental divisions of the X scale.
13.1.1.4.8. Use the [

] key to select the “ Tach Filter Type ”. The options are for a Single pole
filter, a Double pole filter or None.
13.1.1.4.9. Use the keypad to enter the “ Tach Filter Frequency ”. Enter a numeric value equal to
the lowest frequency of interest. The filter will then be effective for that frequency and
all frequencies above that value.
13.1.1.4.10. Press [OK] to return to the Transient Survey Setup screen.
13.1.1.5. – Parms
The “Parms”, or Parameters, (which corresponds to the [F3] key) selection appears at the bottom
center of the “Transient Survey Setup” banner screen shown in paragraph 13.1.1.2. Press the [F3]
key if you wish to define data collection parameters for the survey. If you choose this option, the
following “Transient Parameters Setup” banner screen is displayed.