01/09 ·
uptime
m
e
gazine
vector measurements to be made for
all the guide bearings for early fault
detection and diagnosis by using a
single tacho sensor.
Relay signals are wired to the emer-
gency shutdown system for tripping
the machine if the vibrations indicate
an impending catastrophic failure. A
trip multiplier function in the compact
monitor prevents the normal high vi-
brations due to start-up/synchroniza-
tion from triping the machine.
Measurements
and Signal Conditioning
As shown in Figure 3, each compact
monitor is set up for a specific moni-
toring task. Figure 6 shows the signal
flow diagram for the compact moni-
tors used to monitor the generator
and the turbine guide bearings.
The compact monitor has measure-
ments that are used for safety moni-
toring and machine condition moni-
toring, as summarized in Table 1.
Sensor
(meas.point)
Measurements
Faultsthatcan
bedetectedanddiagnosed
Safety
Monitoring
Condition
Monitoring
Relativeradial
vibration
(allbearings)
n
Overall
(ISO:1Hz/10Hz
- 1kHz)
n
DC (shaft po-
sition)
n
xmagnitude
n
xphase
Bearing damage, lack of lubrica-
tion, overload, wear, misalignment,
unbalance
Tacho
-
n
Speed,phase Phase and triggering used in other
measurements
Absoluteaxial
vibration
(statorcasing)
n
Overall
(ISO:1Hz/10Hz
- 1kHz)
-
Axial stator movement, thrust
bearing problems
Table 1 Meas-
urements pro-
vided by the
four compact
monitors at a
typical end-user
hydro power
station.
Figure 6. Signal flow diagram
for the compact monitor for
monitoring the generator and
turbine guide bearings.