990-04-50-03-00 Overview
When unplanned machinery downtime threatens production targets, the 990-04-50-03-00 from Bently Nevada provides a dependable vibration monitoring solution. This 990 Vibration Transmitter accepts one non-contacting 3300 NSv Proximity Probe and extension cable, converting shaft vibration into a standard 4-20 mA signal. Designed for continuous operation in industrial environments, it delivers accurate, real-time data to your control system.
With a full-scale range of 0-4 mils pp (0-100 μm pp), this transmitter is well-suited for monitoring rotating equipment such as pumps, motors, and fans. Its compact design and DIN clip mounting simplify installation in existing panels. The 990-04-50-03-00 is manufactured in the U.S.A. by Bently Nevada, a trusted name in machinery protection.
Key Features and Technical Specifications
The 990-04-50-03-00 offers several features that enhance reliability and ease of use. Its 4-20 mA output is compatible with most PLCs, DCSs, and SCADA systems, allowing seamless integration. The transmitter operates from a +12 to +35 Vdc power supply, providing flexibility in various power architectures.
- Input: Accepts 1 non-contacting 3300 NSv Proximity Probe and extension cable.
- Power: Requires +12 to +35 Vdc input at the transmitter terminal.
- Output: 4 to 20 mAdc over specified full-scale range in 2-wire configuration.
- Accuracy: Within ±1.5% over specified full-scale range (from TEST signal input to voltage across 250 Ω loop resistance).
- Maximum Loop Resistance: 1,000 Ω including cable at 35 Vdc.
- Current Limiting: 23 mA typical.
- Frequency Response: 5 Hz to 6,000 Hz +0, 3 dB.
- Minimum Target Size: 9.5 mm (0.375 in) diameter.
- Probe Gap: Must be gapped between 0.5 and 1.75 mm (20 and 55 mils) from target.
- NOT OK/Signal Defeat: Output goes to less than 3.6 mA within 100 µs after a Not OK condition; restored within 2-3 seconds after removal.
The current limiting feature protects the loop from overcurrent conditions, while the NOT OK/signal defeat function ensures that a fault is immediately communicated to the control system, preventing erroneous readings. These features contribute to the overall reliability of the monitoring system.
Applications and Use Cases
The 990-04-50-03-00 is ideal for vibration monitoring on rotating machinery in industries such as oil and gas, power generation, and manufacturing. It is commonly used on pumps, compressors, turbines, and electric motors. By providing a continuous 4-20 mA signal proportional to shaft vibration, it enables predictive maintenance strategies that reduce unplanned downtime.
For example, in a petrochemical plant, the transmitter can be installed on a critical pump to monitor bearing wear. Early detection of increased vibration allows maintenance teams to schedule repairs during planned outages, avoiding costly emergency shutdowns. The transmitter's accuracy of ±1.5% ensures that even small changes in vibration are detected, providing confidence in the data.
Installation and Setup
Proper installation is essential for accurate vibration measurement. The 990-04-50-03-00 is mounted using DIN clips and screws (Mounting Option 03). The proximity probe must be gapped between 0.5 and 1.75 mm (20 and 55 mils) from the target to ensure full-scale range. The leadwire length from the Proximitor Sensor Output (BNC connector) to the transmitter should not exceed 3 meters (10 feet).
Wiring is straightforward: connect the probe and extension cable to the transmitter input, and connect the 4-20 mA loop to the control system. The transmitter requires +12 to +35 Vdc at the terminal, and the maximum loop resistance is 1,000 Ω at 35 Vdc. Ensure the power supply is within this range to guarantee proper operation. For hazardous area locations (NonHazardous, Zone 2 or Div 2), a 28 V power supply is specified.
Maintenance and Reliability
From a maintenance engineer's perspective, the 990-04-50-03-00 is designed for minimal upkeep. The transmitter has no moving parts, reducing wear and tear. Periodic inspection of the probe gap and cable connections is recommended to ensure consistent performance. The NOT OK/signal defeat feature automatically alerts the control system if the transmitter detects a fault, allowing prompt corrective action.
Because the transmitter is powered by the loop, there is no need for separate power wiring, simplifying installation and reducing potential failure points. The current limiting feature protects the loop from damage, and the accuracy specification ensures reliable data over time. Regular calibration checks, as per manufacturer guidelines, will maintain measurement integrity.
Compatibility and Integration
The 4-20 mA output makes the 990-04-50-03-00 compatible with a wide range of control systems, including PLCs, DCSs, and SCADA systems. It can be integrated into existing monitoring networks without additional signal conditioning. The transmitter accepts a 3300 NSv Proximity Probe, which is part of the Bently Nevada 3300 series, ensuring seamless compatibility with other Bently Nevada monitoring equipment.
For systems requiring hazardous area certification, the transmitter is available with agency approval options (Option 00 – Not required in this configuration). For Zone 2 or Div 2 locations, a 28 V power supply is specified. Always verify the specific approval requirements for your installation.
Troubleshooting and Common Issues
If the output signal is not within the expected range, check the probe gap and ensure it is within 0.5 to 1.75 mm. Verify that the power supply voltage is between +12 and +35 Vdc at the transmitter terminal. If the output goes below 3.6 mA, the transmitter may be in a NOT OK condition; check for probe damage or cable faults.
Loop resistance should not exceed 1,000 Ω at 35 Vdc; higher resistance may cause the transmitter to operate outside its specified range. If the frequency response seems incorrect, verify that the target size meets the minimum 9.5 mm diameter requirement. For persistent issues, consult the Bently Nevada manual or contact AutoDCSTech for technical support.
Product Support and Availability
The Bently Nevada 990-04-50-03-00 is available through AutoDCSTech. Contact our team to confirm stock and lead times. We are ready to assist with your vibration monitoring needs.
