Description
Bently Nevada 3300/45 Dual Differential Expansion Monitor
Configured for differential expansion measurement in Turbine Supervisory Instrumentation (TSI) networks, the Bently Nevada 3300/45-XX-01-03-00 (base model 3300/45) provides direct acquisition and scaling of rotor axial position relative to the machine casing through eddy-current proximity probes.
Suffix Breakdown & Model Matrix
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Code
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Definition
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3300/45
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Dual Differential Expansion Monitor
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-XX
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Full-scale range option (application-specific calibration)
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-01
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Transducer input compatible with 3300 XL 8 mm, 11 mm, or 50 mm proximity systems
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-03
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FM/CSA Class I, Division 2 hazardous location approval
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-00
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No internal safety barriers installed
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Hardware Specifications
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Parameter
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Specification
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Model Brand
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Bently Nevada
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Origin
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USA
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Weight
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1.0 to 2.0 kg
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Dimensions
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Standard 3300 series rack mount
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Operating Temp
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0 degC to +65 degC
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Power Consumption
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1.5 W nominal
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Input Impedance
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10 kOhm nominal
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Signal Scale Factor
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20 mV/mil or 10 mV/mil jumper selectable
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System Accuracy
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±0.33% typical, ±1% max at +25 degC
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Recorder Outputs
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4-20 mA, 0 to -10 Vdc, or +1 to +5 Vdc
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Buffered Output Impedance
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100 Ohm
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Alarm Setpoints
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Four per channel, 0-100% FS, ±1.6% resolution
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Display
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63-segment vertical LCD bargraph per channel
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LED Indicators
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OK (green), ALERT (yellow), DANGER (red), BYPASS (red)
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Relative Humidity
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Up to 95%, non-condensing
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Eddy-Current Probe Scaling and Gap Voltage Validation
The 3300/45 employs fixed scaling factors aligned with eddy-current probe sensitivity, supporting 20 mV/mil or 10 mV/mil configurations. Gap voltage validation targets -10 VDC for probe installation verification, ensuring linear measurement range and avoiding probe/casing contact. Cross-talk suppression between channels is implemented via independent signal conditioning circuits to maintain rotor dynamics accuracy under high electromagnetic interference conditions.
Frequently Asked Questions
Q: Does the 3300/45 support hot-swap replacement in an operational rack?
A: No. Remove power from the rack before replacing the monitor to prevent damage to the backplane interface and ensure proper transducer re-calibration.
Q: Can Channel B be disabled if only one measurement point is required?
A: Yes. Channel B can be bypassed via configuration jumpers without affecting Channel A operation.
Q: What is the expected switching delay for alarm relays?
A: Relay actuation occurs within 100 milliseconds of exceeding the setpoint threshold, subject to debounce filtering settings.
Field Installation Guidelines
Mount the monitor in a standard 3300 series rack using the supplied guide rails. Ensure transducer cables are routed separately from power wiring to minimize electromagnetic interference. Ground shield terminations at the monitor end only, maintaining continuity to the system earth bus. Verify gap voltage at installation using a digital voltmeter referenced to the monitor’s common terminal. Perform full functional testing after installation by simulating probe movement across the calibrated range.
