GE 3300, 3320, Bently Nevada 3300/20 Specifications
3300/20 Dual Thrust Position Monitor
BUFFERED TR ANSDUCER S
DANGER
A
GAP
ALERT
B
BYPASS
ALERT
DANGER
A B
OK
3300/20
D D
12
4 R
N
T
0 25
20
S
P
A
C
E
M
E
L
15
10
U N
T
E
C
O
8
5
I 0
R
N
25
20
T
A
10
15
U
E
N
T
O
C
M
E
E
C
0
5
S
L
P
I
vdc
16
N 20
M
S
L
I
/
5
10
15
M
O
R 20
25
24
20 N
10
5
L
/
S
I
M
15
M
R
O
25
DUAL THRUST
MONITOR
Description
The 3300/20 Dual Thrust Position Monitor provides early warning of thrust
bearing failure. It continuously measures and monitors two independent
channels of shaft axial position relative to the axial clearances within the
machine. Ideally, the axial probes are installed to observe the thrust collar
directly, so the measurement represents the position of the collar relative to the
thrust bearing clearance.
Caution
Because thrust measurements are made by observing the gap voltage of the
proximity probe used as an input, a transducer failure (gap out of range) can be
interpreted by the monitor as thrust position movement and result in a false
thrust alarm. For this reason, Bently Nevada LLC. does not recommend the use
of a single probe for thrust position applications. Instead, these applications
should use two proximity probes observing the same collar or shaft and
configure the monitor as AND voting whereby both transducers must
simultaneously reach or exceed their alarm setpoints for the monitor’s alarm
relays to actuate. This 2-out-of-2 voting scheme (also known as AND voting)
provides optimum protection against both false trips and missed trips. While the
3300/20 monitor can be programmed for either single voting (OR) or dual voting
(AND), dual voting is strongly recommended for all thrust position applications.
Caution
Probe adjustment and range is critical in this monitor for machinery protection.
Improper adjustment of the transducer may prevent the monitor from alarming
(no machinery protection). For proper adjustment, follow instructions in the
manual.
Specifications and Ordering Information
Part Number 141500-01
Rev. J (06/07)
Page 1 of 6
Specifications
• 0 to -10 Vdc: ±1.1% of
signal, ±15 mV offset.
Inputs
Signal:
Accepts one or two proximity
probe signal inputs.
Input
Impedance:
10 k Ω.
Sensitivity:
User-programmable for 200
mV/mil (8 V/mm) or 100 mV/mil (4
V/mm).
Power:
Nominal consumption of 1.5
watts.
Signal Conditioning
Accuracy:
Within ±0.33% of full-scale
typical, ±1% maximum. All
specified at temperature of +25°C
(+77°F).
Outputs
Recorder:
User-programmable for +4 to +20
mA, 0 to -10 Vdc, or +1 to +5 Vdc.
Voltage or current outputs are
proportional to programmed
monitor full-scale. Independent
recorder outputs are provided for
each channel. Monitor operation
is unaffected by short-circuits on
recorder outputs.
Recorder
Accuracy (in
addition to
signal
conditioning
accuracy) at
+25°C (+77°F):
• +4 to +20 mA: ±0.7% of
signal, ±0.09 mA offset.
• +1 to +5 Vdc: ±1.1% of
signal, ±10 mV offset.
Output
Impedance
(voltage
outputs):
100 Ω. Minimum load resistance
is 10 k Ω.
Voltage
Compliance
(current
outputs):
0 to +12 Vdc range across load.
Load resistance is 0 to 600 Ω
when using +4 to +20 mA option.
Buffered
Transducer
Outputs:
There is one coaxial connector
per channel on the front panel
and one terminal connection per
channel on the rear panel. All are
short-circuit protected.
Output
Impedance:
100 Ω.
Transducer
Supply Voltage:
User-programmable in power
supply for -24 Vdc or -18 Vdc.
Current limited on individual
monitor circuit board.
Note: Contact your nearest sales professional if 3000 series
transducers are to be used in the monitoring system which also
uses 3300 and/or 7200 series transducers.
Alarms
Alarm
Setpoints:
Both alarms (Alert and Danger)
are bi-directional (normal and
counter), digitally adjustable from
0 to 100% of full-scale and can be
set within LCD resolution (±1.6%)
to desired level. Once set, alarms
are repeatable within 0.39% of
full-scale.
Specifications and Ordering Information
Part Number 141500-01
Rev. J (06/07)
Page 2 of 6
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