Product Introduction
When a vibration monitoring system fails or provides unreliable readings, the Bently Nevada 990-04-50-03-00 990 Vibration Transmitter delivers precise displacement measurements. This module accepts one non-contacting 3300 NSv proximity probe and extension cable, converting probe signals into a 4-20 mA output. Its full-scale option of 0-4 mils pp (0-100 μm pp) makes it ideal for critical machinery protection.
Technical Specifications Breakdown
The Bently Nevada 990-04-50-03-00 offers key specs that ensure reliable vibration monitoring:
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Power Supply: +12 to +35 Vdc input at the transmitter terminal.
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Output Signal: 4-20 mAdc over specified full-scale range, 2-wire configuration.
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Loop Accuracy: Within ±1.5% over full-scale range (measured from TEST signal to 250 Ω load).
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Frequency Response: 5 Hz to 6,000 Hz +0, -3 dB.
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Maximum Loop Resistance: 1,000 Ω including cable at 35 Vdc.
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Current Limiting: 23 mA typical.
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Weight: 0.43 kg (0.9 lbm).
Application Scenarios
In power generation, petrochemical, and heavy machinery environments, the Bently Nevada 990-04-50-03-00 excels at monitoring shaft relative vibration. For example, on a steam turbine, the 990-04-50-03-00 provides continuous 4-20 mA output to a DCS or PLC. Its fast NOT OK response (signal drops below 3.6 mA within 100 µs) immediately alerts operators to probe faults, preventing catastrophic damage.
Troubleshooting & Common Issues
A common problem in vibration monitoring is false readings due to improper probe gap. The Bently Nevada 990-04-50-03-00 requires a probe gap between 0.5 and 1.75 mm (20-55 mils). If the gap is out of range, the transmitter may not achieve full scale. Another issue is loop resistance exceeding 1,000 Ω, which can degrade accuracy. Use the maximum loop resistance spec to verify cable length. The built-in NOT OK/signal defeat feature ensures the output goes to less than 3.6 mA within 100 µs of a fault, and restores 2-3 seconds after removal.
Maintenance & Reliability
With non-interacting external zero and span adjustments, the Bently Nevada 990-04-50-03-00 simplifies calibration. No periodic recalibration is required under normal conditions, but verify probe gap during installation. The transmitter can be mounted using DIN clips and screws (mounting option 03). Its compact 0.43 kg design fits easily into existing cabinets. The NOT OK signal defeat feature ensures system integrity during probe or cable faults.
Selection Guide & Purchasing Advice
Before purchasing, verify that your system uses a 3300 NSv proximity probe and that the cable length does not exceed 3 meters (10 feet) for the Proximitor Sensor Output (BNC connector). Ensure supply voltage between 12 and 35 Vdc. For non-hazardous, Zone 2, or Div 2 locations, the Bently Nevada 990-04-50-03-00 is suitable. As a trusted supplier, PLC Source PRO (available at ubest101) stocks this module with fast shipping. Check system length option (5.0 meters in this configuration) and mounting option (DIN clips/screws) to match your setup.