ACES SYSTEMS Cobra II, Руководство пользователя

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Gen II
User Manual
10-16 – Fan/Turbine Balance Chapter 10 Revision 2.10, Apr 2020
10.1.6.2. Use the [

] to select the “ Tach Chan ” (tachometer channel) you will use for this
job. Be sure the channel you select here is the channel you actually connect the
tachometer-input signal to when setting up the equipment. Press the [

] key to
move to the next field.
10.1.6.3. Use the [

] key to select the “ Tach Type: ” The analyzer will process the signal
of several tooth types, magnetic pickups, tachometer generators and optical
sensors. Optical sensors include the Phototach and Lasetach. The available
selections are “Optical”, “Mag P/U”, “Mod Tth”, and “Adj Tth”. If “Adj Tth” is
selected the additional “Delta(%):” field will appear after Tach Pos (FLA). See
paragraph 10.1.6.5 below for more on this setting. Press the [

] key to move to
the next field.
10.1.6.4. Use the [

] to select “ Tach Pos (FLA): ” (Tachometer position, from Forward
Looking Aft). This is the clock position where the tachometer triggers during the
fan rotation as viewed from forward of the engine looking aft into the intake. The
selections are in whole hours from 1 to 12. If you are unsure of the location of the
tach trigger event, use the [

] key to select “UNK”. Press the [

] key to move to
the next field.
10.1.6.5. Use the keypad to enter a value in the “Delta(%): ” field. This value will be the
amount that the shifted tooth detection is shifted. Valid entries are from 1.0%
through 16% in signal shift.
10.1.6.6. Use the [

] key to select the “ Tach Filter Type ”. The options are for a Single
pole filter, or a Double pole filter or None.
10.1.6.7. 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.
10.1.6.8. Use the [

] key to select the “ Full Scale Vibration ”. This should be the highest
amplitude of vibration you would reasonably expect to see during a typical
balance job. This value should be enough above the maximum allowable vibration
for the engine so that any amplitude in excess of that limit can be readily seen.
Use the [

] key to move to the next field.
10.1.6.9. Use the [

] key to select the “ Sensor Type ” you will use for this balance. If the
sensor you intend to use is not among those listed, see Chapter 22, Analyzer
Management, on setting up a new sensor. Use the [

] key to move to the next
field.