Example Low-Pass Filter Configuration - GE Bently Nevada 3300/25 Operation Manual

Section 19 - Appendix B–Filter Board Options PWA 79562-01 and PWA 105521-01
19.13

Example Low-Pass Filter Configuration

This example shows how to configure channel B with a low-pass filter that has a corner
f
frequency, , of 7500 CPM (125 Hz). (The resulting -3dB point is at 1.06 x
LP
(132.5 Hz). The Low-Pass Filter is before the Integrator/Gain Stage.
NOTE: Since this corner frequency is listed in
configure the filter from the table. This example is meant to illustrate the calculation
procedure used when the desired corner frequency is not given in the table.
Follow the steps outlined in the General Procedure,
steps.
1. Set the type of filter as a Low-Pass filter as shown in the table of
table in Section 19.5
On the Filter Board
Install:
Remove:
2. Set the Low-Pass Filter before the Integrator/Gain Stage as shown in the table for
channel B in Section
On the Main Board
Install:
Remove:
On the Filter Board
Install:
Remove:
Follow the steps outlined in General Procedure,
low-pass corner frequency,
3. Set the anti-aliasing filter. Select the anti-aliasing corner frequency
limit the input signal.
4. Select a value, K. In this case,
is 19.188.
shows that for a Low-Pass filter for channel B
W21 and W58
W20 and W59
19.6.
W3A,W3C, and W5B
W3B
W61
W41,W60,W85 and W86
f
.
LP
f = 5
AA
f
is between 120 Hz and 4.81 kHz, so the value of K
AA
Section 19.10, you would normally
Section 19.4
Section 19.4, to set the
× 125 = 625
f
or 7950 CPM
LP
for the following two
Section 19.5. The
f
to band-
AA
75