Bently Nevada 3300/50, Operation Manual

Page: 90 / 122

•
Tachometer Maintenance
83871-01
25 Test Alerts (Rotor Accel Tach.) (Cont.)
6. Adjust the function generator frequency until the
Tachometer displays an RPM reading above the RPM
Alert over speed setpoint or below the RPM Alert
under speed setpoint.
7. Verify that the RPM Alert LED turns on (Flashing if
the first out option is selected), and that the RPM Alert
relay has changed state.(The Relay will not change
state if the Alert 1 Relay has been Bypassed. See
section 19.)
8. Press the RESET switch on the System Monitor and
verify that the RPM Alert LED remains on steady.
9. Adjust the function generator frequency until the
Tachometer displays an RPM/MIN reading above the
RPM/MIN Alert setpoint.
NOTE: Rotor Acceleration (RPM/MIN) is the rate of
change o f Rotor Speed (RPM). Therefore, t h e
RPM/MIN display increases as the function generator
frequency is increased. The RPM/MIN display returns
to Zero if the function generator frequency remains
constant.
10. Verify that the RPM/MIN Alert LED turns o n
(Flashing if the first out option is selected).
11. Verify that the RPM/MIN Alert relay has changed
state.(The Relay will not change state if the Alert 2
Relay has been Bypassed. See section 19.)
12. Adjust the function generator until the Tachometer
displays an RPM reading below the RPM Alert over
speed setpoint or above the RPM Alert under speed
setpoint. Leave the generator at this frequency long
enough for the RPM/MIN display to settle back to
zero.
13. Press the Reset switch on the System Monitor and
Verify that the RPM and RPM/MIN LEDs go out.
• 14. Connect all field wiring.
z e
TACHOMETER
3600
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R P M / M I N
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W O M B TleMMOPSEES
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