Propeler fan balancing/structure movement
Propeler fan balancing/structure movement
(OP)
I am not in the same league as most of the forum members, but I will ask
the question anyway.
A balance report on a propeler fan on a cooling tower plotted the initial
magnitude and phase of imbalance. This was followed by magnitude
and phase of trial weights, (5 trial weights). A line was connected to
the initial balance magnitude and phase, the first trial weight magnitude
and phase. and so on to the 5th magnitude and phase. The unbalance
was lowered significantly. However, there was a comment on this plot that
said that these lines indicated structure movement. I thought
that the magnitude and phase would always change with trial weights.
How does the plot indicate "structure movement"?
Thanks
the question anyway.
A balance report on a propeler fan on a cooling tower plotted the initial
magnitude and phase of imbalance. This was followed by magnitude
and phase of trial weights, (5 trial weights). A line was connected to
the initial balance magnitude and phase, the first trial weight magnitude
and phase. and so on to the 5th magnitude and phase. The unbalance
was lowered significantly. However, there was a comment on this plot that
said that these lines indicated structure movement. I thought
that the magnitude and phase would always change with trial weights.
How does the plot indicate "structure movement"?
Thanks





RE: Propeler fan balancing/structure movement
That is, if the imbalance is halved, the vibration of the structure at that frequency should halve, if there are no other sources of vibration.
In practice things are rarely that simple, of course.
Cheers
Greg Locock
RE: Propeler fan balancing/structure movement
locations you will have a plot similar to this:
0
1
2 5
3 4
There are four quadrants corresponding to the four possible phase
readings from 0 degrees to 360 degrees. If you connect the initial unbalance magnitude and the phase angle at 0 to point 1, point 2, and so on. How does this indicate structure movement?
RE: Propeler fan balancing/structure movement
Cheers
Greg Locock