Overview of the Bently Nevada 991-06-50-02-00 Thrust Transmitter
When axial shaft position monitoring demands precision and reliability, the 991-06-50-02-00 from Bently Nevada delivers. This probe vibration transmitter converts proximity probe signals into a standard 4-20 mA current loop, making it a practical choice for turbine and compressor protection systems.
Designed for DIN rail mounting, the 991-06-50-02-00 integrates easily into existing control panels. Its compact form factor and straightforward wiring reduce installation time, while the non-interacting zero and span adjustments simplify calibration.
Key Features and Technical Specifications
- Full-scale range: 0.6-0-0.6 mm, suitable for 25-0-25 mils current loop linear ranges.
- System length option: 5.0 meters (16.4 feet) cable.
- Mounting option: Bulkhead screws for secure probe installation.
- Output signal: 4-20 mA DC in a 2-wire configuration.
- Power requirement: +12 to +35 Vdc input at the transmitter terminal.
- Linear range: 0.25 to 1.65 mm for Prox Out.
- Loop accuracy: Within ±1.5% over the specified full-scale range (typical).
- Maximum loop resistance: 1,000 ohms including cable at 35 Vdc.
- Current limiting: 23 mA typical.
- Operating temperature: -35°C to +85°C (-31°F to +185°F).
- Storage temperature: -51°C to +100°C (-60°F to +212°F).
- Weight: 0.43 kg (0.9 lbm).
One distinctive feature is the Not OK/Signal Defeat function. When a Not OK condition occurs, the output drops to less than 3.6 mA within 100 microseconds, ensuring that downstream monitoring systems detect a fault immediately. This rapid response is critical for protecting rotating machinery from undetected axial displacement.
Applications and Use Cases
The 991-06-50-02-00 is engineered for axial thrust measurement in turbomachinery. It accepts a single non-contacting 3300 NSv proximity probe and extension cable, making it a direct fit for many existing Bently Nevada monitoring setups.
Typical applications include steam turbines, gas turbines, and large compressors where axial shaft position must be continuously monitored. The 4-20 mA output allows easy integration with PLCs, DCSs, and standalone trip units.
Installation and Setup
Mount the transmitter on a standard DIN rail in a suitable enclosure. Connect the proximity probe and extension cable to the transmitter input. Then wire the 4-20 mA loop to the receiving device, observing the 2-wire configuration.
Power the transmitter with +12 to +35 Vdc at the terminal. Ensure the loop resistance does not exceed 1,000 ohms at 35 Vdc to maintain specified accuracy. Use the external zero and span adjustments to calibrate the output to the desired full-scale range.
For the bulkhead mounting option, secure the probe using the provided screws. Verify that the system length of 5.0 meters matches your installation requirements.
Maintenance and Reliability
Regularly inspect the transmitter and probe connections for signs of wear or corrosion. Verify the output signal during routine checks to ensure it remains within the specified accuracy of ±1.5%.
Because the transmitter operates over a wide temperature range, it suits harsh environments. However, periodic verification of the Not OK/Signal Defeat function is recommended to confirm that fault detection remains operational.
Compatibility and Integration
The 991-06-50-02-00 is designed to work with Bently Nevada 3300 NSv proximity probes and extension cables. Its 4-20 mA output is universally compatible with most industrial control systems, including PLCs and DCSs.
For existing Bently Nevada monitoring systems, this transmitter can serve as a direct replacement or upgrade, providing a standardized current loop output for axial position monitoring.
Troubleshooting and Common Issues
If the output signal is not present, check the power supply voltage at the transmitter terminal. Ensure it is within +12 to +35 Vdc.
If the output is saturated or erratic, inspect the probe gap and cable connections. The linear range is 0.25 to 1.65 mm, so the probe must be positioned within this range for accurate measurement.
If the Not OK function activates unexpectedly, verify the probe and extension cable integrity. A damaged cable or probe can cause a Not OK condition.
Product Support and Availability
AutoDCSTech stocks the Bently Nevada 991-06-50-02-00 thrust transmitter. Contact our team for current availability and lead times. We are ready to assist with your industrial automation needs.
