New principle for vibratory system
– designed to reduce the effects of force relations
The disadvantages of the former solutions are the considerable effects of force relations. As a
result the plane separator circuit mostly had to form the difference between high measured
values in the transducer planes in order to calculate the unbalances present in the correction
planes. If sensitivity substantially of one transducer changed by a certain percentage under
different influences, the calculated difference, that is the reading of unbalance present in the
correction planes, would change disproportionately.
The problem of the effects of force relations will now be illustrated in Fig. 1 and the
following derived algorithms. To make the problem quite clear we assume that an unbalance
U
R
is present in the right-hand correction plane only, this unbalance being calculated by the
plane separator circuit on the basis of data measured in the planes R and L.
c
L
b
a
R
-L
R
R
U
U
R
U
R
L
U
Fig. 1 Illustration of the effect of force relations at an increasing distance (a+b)
Following the condition
0=
∑
Moments
the measured value L is
()
c
baUaU
L
RL
+
+⋅
=
or
()
c
baU
L
R
+⋅
=
, if . 0=
L
U
Analogously the measured value R is
() ( )
c
cbaUcaU
R
RL
+⋅++⋅
−=
or
()
c
cbaU
R
R
++⋅
−=
, if 0=
L
U
Following the condition
0=
∑
ForcesTransverse
the plane separator circuit calculates that
()
RLU
R
+−= .
As the measured value
L is oppositely directed to R, U
R
is practically the difference between
the absolute measured values
L and R .
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