SPM leonova emerald, User Manual

Page: 159 / 170

F
Rotor balancing
F:9
Four run method
Using four runs, three of them with the same trial
weight fixed first at 0°, then at 120° and 240° along
the rotor circumference, is the traditional balancing
method.
It is important to run the machine at the same speed
at all measurements.
Traditionally, the position and weight of the balancing
weight were calculated by drawing a graph of the
vibration vectors. This part of the work is now done
by Leonova: after the last run, the instrument displays
the balancing weight in grams (ounces) and its position
in degrees (measured from the point where the first
trial weight was placed).
Two run method
The two run method work with synchronized vibration
measurement. This requires a trigger pulse from a
tachometer. Each measurement starts in exactly the
same shaft position.
The tachometer position becomes part of the reference
system needed to calculate the angles between 0°
(the position of the trial weight), the position of the
‘heavy spot’ and the position of the artificial unbalance
created by the trial weight.
The tachometer must not be moved between measure-
ments.
Weak
direction