Smart Avionics PB-4, User Interface Manual

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to capture all the points needed. When using dual accelerometers, only 3 runs
are required as points for both planes are captured at the same time.
9.3.1. Single accelerometer procedure
The two plane balancing procedure when using a single accelerometer is as
follows:
• Mount the accelerometer so that it is sensing vibration in measurement
plane 1.
• With no trial mass attached in either correction plane, capture a couple of
points
• Attach a trial mass so that it is in correction plane 1 and capture a couple
of points, mark the position of the mass and remove it.
• Now attach the same mass so that it is in correction plane 2 and capture
a couple more points. Mark the position of the mass and remove it. You
now have data for the 3 points on the left hand side of the dialog.
• Move the accelerometer so that it is now sensing vibration in measurement
plane 2.
• As above, capture 3 further sets of readings for the no-mass, mass in
correction plane 1 and mass in correction plane 2 configurations to provide
the data for the 3 points on the right hand side of the dialog. It is important
that when you attach the trial mass you use the same positions as you did
previously. It is also important that all of the points have the same RPM.
• Enter all 6 points into the two plane balancing dialog and you will get two
solutions, one for the mass in each correction plane.
9.3.2. Dual accelerometer procedure
The procedure when using dual accelerometers is as follows:
• Mount the two accelerometers such that one is sensing the vibration in
measurement plane 1 and the other is sensing the vibration in measurement
plane 2. Select Rotor Mode and set the axis selectors to the two
accelerometer channels you are using (i.e. X and X2). Set the profile to
None . The points list and polar chart will now display the points from both
accelerometers.
• With no trial mass attached in either plane, capture a couple of points. The
PB-4 will capture points from each accelerometer at the same time.
• Attach a trial mass so that it is in correction plane 1 and capture a couple
of points. Mark the position of the mass and remove it.
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Single accelerometer procedure