0
uptime
m
e
gazine · 01/09
Installation
X-Y displacement sensors are in-
stalled on the three guide bearings
as shown in Figure 3. In smaller
hydro units such as in this example,
access may be difficult for placing
the displacement sensors directly
at the bearing. This is the case for
the lower generator guide bearing
as shown in Figure 4 (right), where
the radial X-Y sensors are placed as
close as possible to the lower gen-
erator bearing housing. In this case
a velocity sensor is used for monitor-
ing the axial vibration in place of the
axial displacement sensor. The ve-
locity sensor is located on top of the
generator cover housing, as shown
in Figure 4 (left).
The four compact monitors are
typically installed in a cabinet in the
instrument room of the power sta-
tion, as shown in Figure 5. The tacho
signal is wired to the three monitors
at the bearings. This allows triggered
Figure 3. Typical
monitoring sys-
tem configura-
tion for the com-
pact monitor.
Displacement
sensors are
shown in red,
tacho in yellow
and the velocity
sensor in blue.
Figure 4. Examples showing sensor
installation on the hydro generating
units. On the upper left is the velocity
sensor on the generator top cover for
monitoring axial vibrations. The lower
left and upper photos show the X-Y
radial displacement sensors mounted
just over the turbine guide bearing.
On the lower right are the X-Y radial
displacement sensors mounted below
the lower generator guide bearing.
Figure 5. Typical
cabinet installa-
tion for the com-
pact monitors.