Compact Axial Displacement Monitoring Device for Rotating Machinery Protection
The Bently Nevada 991-05-70-01-01 991 Thrust Sensor is a reliable axial displacement monitoring transmitter designed for continuous thrust position measurement in rotating equipment. Developed for applications such as centrifugal compressors, pumps, motors, and industrial fans, the unit provides a proportional 4–20 mA output signal that can be directly integrated into machinery control, PLC, DCS, and monitoring systems.
Built around Bently Nevada’s proven 3300 NSv proximity probe technology, the 991-05-70-01-01 combines sensing, signal conditioning, and transmission functions into a compact industrial package. It accepts input from a 3300 NSv probe and converts shaft axial movement into an engineering-unit output signal, supporting reliable thrust bearing protection and predictive maintenance strategies.
The 05-70-01-01 configuration represents a 0.5 mm full-scale measurement range, 7.0 m system length, 35 mm DIN-rail mounting, and CSA Division 2 approval option, making it suitable for industrial installations requiring compact and dependable machinery monitoring.
Technical Specifications
| Parameter | Specification |
|---|
| Manufacturer | Bently Nevada |
| Model Number | 991-05-70-01-01 |
| Product Type | 991 Thrust Sensor / Thrust Transmitter |
| Measurement Type | Axial displacement (thrust position) |
| Full-Scale Range | 0.5 mm |
| System Length | 7.0 m (23 ft) |
| Input Sensor | Bently Nevada 3300 NSv Proximity Probe |
| Output Signal | 4–20 mA proportional signal |
| Power Supply | 12–35 VDC loop powered |
| Wiring Type | Two-wire transmitter |
| Mounting Method | 35 mm DIN-rail mounting |
| Sensor Technology | Integrated Proximitor® sensor |
| Diagnostic Terminals | PROX OUT and COM |
| Approval Option | CSA Division 2 |
| Operating Temperature | -40°C to +85°C |
| Storage Temperature | -52°C to +177°C |
| Transmitter Weight | Approx. 0.43 kg |
| Total System Weight | Approx. 0.82 kg typical |
| Dimensions | Approx. 82 × 35 × 75 mm |
Industrial Applications
The 991-05-70-01-01 Thrust Sensor is designed for equipment where accurate shaft axial position measurement is critical.
| Industry | Typical Equipment |
|---|
| Oil & Gas | Centrifugal compressors, process pumps |
| Petrochemical | Rotating process machinery |
| Power Generation | Turbine auxiliary equipment |
| Manufacturing | Motors, blowers, industrial fans |
| Water & Utilities | Large pumping systems |
| OEM Machinery | Compressor and pump packages |
Common applications include:
-
Continuous thrust position monitoring
-
Thrust bearing protection
-
Rotating equipment condition monitoring
-
Machinery alarm and shutdown systems
-
Predictive maintenance programs
-
Control system feedback applications
Product Advantages
Integrated Proximitor® Sensor Technology
The 991 Series incorporates integrated Proximitor® electronics, eliminating the requirement for a separate proximity signal conditioner. This reduces cabinet space requirements, simplifies wiring, and improves system installation efficiency.
Accurate Axial Position Measurement
The transmitter provides a stable proportional output representing shaft axial displacement, enabling operators to monitor thrust conditions and identify potential mechanical issues before equipment damage occurs.
Optimized 7 Meter Probe System
The 70 configuration supports a 7.0 m total system length, providing flexibility for machinery installations where sensor placement requires extended cable routing between the probe and transmitter.
Compact DIN-Rail Installation
The 01 mounting option allows direct installation on standard 35 mm DIN rails, making the transmitter ideal for OEM control cabinets and compact machinery monitoring panels.
Standard 4–20 mA Industrial Output
The analog output allows easy connection to common automation systems, including PLC, DCS, and SCADA platforms, without requiring additional signal conversion equipment.
Designed for Harsh Industrial Environments
With industrial-grade construction and hazardous-area approval capability, the transmitter is suitable for demanding applications where reliability and continuous operation are essential.
Technical FAQs
1. What is the Bently Nevada 991-05-70-01-01 used for?
It is used to measure shaft axial displacement and provide a proportional 4–20 mA signal for thrust monitoring and machinery protection.
2. What type of measurement does this sensor perform?
The unit measures axial displacement (thrust position) of rotating machinery shafts.
3. What proximity probe is compatible with this transmitter?
The transmitter is designed to work with the Bently Nevada 3300 NSv proximity probe system.
4. What does "05" represent in the model number?
The 05 option indicates the transmitter’s full-scale measurement range of approximately 0.5 mm.
5. What does "70" represent?
The 70 option identifies the 7.0 meter system length configuration.
6. What mounting method does this model use?
The 01 mounting option specifies 35 mm DIN-rail mounting.
7. What output signal does the transmitter provide?
It provides a standard 4–20 mA proportional analog output for machinery control systems.
8. Does the unit require an external Proximitor module?
No. The Proximitor sensor electronics are integrated into the transmitter assembly.
9. What diagnostic connections are available?
The transmitter provides PROX OUT and COM terminals for diagnostic access and troubleshooting.
10. Which machines commonly use the 991-05-70-01-01?
It is commonly applied to centrifugal compressors, small pumps, motors, fans, and other rotating machinery requiring thrust position monitoring.
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