CEMB USA N500 - Manual (Page 30)

5 - 6 Vibrometer mode
Monitoring in speed
In many situations it could prove useful to associate the vibration value with that of the
speed of rotation of a shaft; in this way it could be possible to investigate, for example,
how the overall or the synchronous component varies during machine starting or stop
phase, with identification of any critical zones or zones with risk of resonance, which are
best to avoid.
In order to be able to use this function, it is essential to have the tachometric signal;
therefore it is necessary
- to apply a reflecting label on the rotor as reference mark (0°). Starting from this
position, proceed to measure the angles in direction opposite to that of the shaft
rotation.
–
connect the photocell and position it correctly (50 – 400 mm), so that the led
located behind it lights up once for each rev. when the reference mark is
illuminated by the light beam. If the operation is not regular, either retract or
approach the photocell, or else incline it with the respect to the workpiece surface.
Speed monitoring can be performed according to two different modes, namely:
- monitoring of overall vibration (overall)
- monitoring of modulus and phase of the vibration synchronous with the speed
of rotation (1xRPM)
An icon on the top part of the page indicates which mode is currently selected; this mode
can be changed by pressing .
Two graphs are always displayed simultaneously in a synchronous monitoring. Such graphs
can be:
–
modulus and phase of the vibration of channel 1
–
modulus and phase of the vibration of channel 2
–
modulus of the vibration for both channels
To switch between the various modes, press
After pressing a vibration measurement is made and a speed reading taken,
these are then plotted by a point on the graph; such measurements are repeated
automatically, with a new point added each time to the graph.
For the sake of convenience, the current rotor speed, expressed in RPM, is displayed at the
top right, alongside the symbol