X20 system modules • Other functions • X20CM4810
2106
X20 system User's Manual 3.10
K(t) value
The K(t) is described in the VDI 3832 guideline and is calculated from the RMS value and the peak value of a
broadband time signal of the oscillation acceleration.
This ratio correlates to the reference values. The reference values should be measured by the operator shortly
after the running-in time. These values can be classified as "System OK" and are therefore the initial values.
The K(t) value decreases with progressive wear. This allows it to be classified into three groups:
•
Undamaged
•
Early damage
•
Pronounced damage
The advantage of the K(t) value is that does not change much, even when damage is severe.
K(t) =
ɑ
ɑ
RMS
p
(0)
(0)
·
(t):
ɑ
ɑ
RMS
p
(t):
The following applies:
Formula symbols
Description
Characteristic value in the module
ɑ
rms
(0)
RMS value of the reference value
RmsHighFrequencyRef01-04
RmsRawRef
ɑ
p
(0)
Maximum value of the reference value
PeakHighFrequencyRef
PeakRawRef
ɑ
rms
(t)
Current RMS value
RmsHighFrequency
RmsRaw
ɑ
p
(t)
Current maximum value
PeakHighFrequency
ReakRaw
Example
Possible progression of the (K/t) characteristic value
K(
t)
[1
]
Time [t]
Possible running-in time
1
Figure 677: K(t) value progression
Vdi3832KtHighFrequency
K(t) value according to the VDI 3832 guideline formed from the high-frequency portions of the input signal
("PeakHighFrequency" and "RmsHighFrequency") of the oscillation acceleration in the frequency range between
"HighFrequencyConfig01" (500 Hz – 2 kHz) and 10 kHz.
Example:
Gear damage
Vdi3832KtRaw
K(t) value according to the VDI 3832 guideline formed from the raw signal of the oscillation acceleration up to the
configured maximum frequency ("MaxFrequencyRaw01") of the respective channel.
Example:
Suboptimal lubrication of electric motors
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