SPM leonova emerald, User Manual

Page: 60 / 170

B:26
General measurement functions
B
The purpose of a spectrum is to reveal line patterns as-
sociated with machine or bearing faults. Characteristic
for many fault patterns is the presence of ‘multiples’
or ‘harmonics’, which means that the line (or group of
lines) is repeated two, three or more times further up
in the spectrum. The spacing is 1Z, 2Z, 3Z, ... nZ, where
1Z = the frequency of the first harmonic.
With the cursor (1) positioned on a spectrum line that
has a significant amplitude, press F2 (‘Cursor’) > F3
(‘Harmonics’) (2).
A series of numbered, green arrows (3) now show up
in the spectrum. Number 1 is in the cursor position.
Numbers 2, 3, etc. are the harmonics. They are evenly
spaced along the frequency axis at Z intervals. Mov-
ing the cursor one step and back will again display its
position and thus Z.
To remove the arrows from the spectrum, press F3
(‘Harmonics’) (2) again.
In the second screen shot (right), the cursor is po-
sitioned on a different spectrum line in the pattern
and the harmonics shown. This spectrum line has one
harmonic within the displayed frequency range. Z in
this case is doubled.
Please note that cursor number 1 in the lower figure
also matches the symptom ‘Bearing, BPFI’. This shows
that the symptom is configured to look for multiples
of the basic pattern. More about symptoms overleaf.
Z
Z
3
1
Z
Z
Z
Z
Z
Z
Z
2