Description
Product Description
The Bently Nevada 3500/72M (P/N 140734-08) is a four-channel position monitoring module designed for use within the 3500 Machinery Protection System. The module interfaces with proximity probe systems to perform continuous position and displacement measurement on rotating and reciprocating equipment.
This monitor processes raw probe signals into calibrated engineering values including shaft axial position, rod position, thermal expansion, and dynamic displacement measurements. Integrated alarm logic enables continuous comparison against configured operating limits for machinery protection and condition assessment.
The module is commonly applied in turbine, compressor, and thrust monitoring systems where accurate displacement monitoring and shutdown protection are required.
Core Functions
- Continuous shaft position monitoring
- Rod position measurement for reciprocating compressors
- Dynamic displacement analysis
- Axial thrust monitoring
- Thermal growth and casing expansion detection
- Alarm processing with programmable thresholds
- Buffered signal output for external diagnostics
- Keyphasor® phase reference support
Technical Specifications
| ParameterSpecification |
|
| Product Type |
Position Monitor Module |
| Model |
3500/72M |
| Part Number |
140734-08 |
| System Compatibility |
Bently Nevada 3500 Series |
| Monitoring Channels |
4 independent channels |
| Supported Sensors |
Proximity probes and Proximitor® systems |
| Compatible Probe Sizes |
5 mm, 8 mm, 11 mm |
| Input Signal Types |
DC gap voltage and dynamic displacement |
| Typical Gap Voltage Range |
-10 VDC to -22 VDC |
| Typical Displacement Range |
Up to 2 mm depending on probe type |
| Input Impedance |
High impedance |
| Measurement Accuracy |
±0.5% of full scale |
| Resolution |
Better than 0.1% of full scale |
| Update Time |
Less than 100 ms |
| Power Consumption |
Approximately 7 W |
| Rack Format |
Single-slot 3500 module |
| Country of Origin |
USA |
Measurement Capabilities
Each channel can be configured for one or more of the following monitoring functions:
| Measurement FunctionDescription |
|
| Shaft Position |
Continuous axial displacement monitoring |
| Rod Position |
Position tracking for reciprocating machinery |
| Dynamic Displacement |
AC vibration and movement analysis |
| Thermal Expansion |
Machine casing or rotor growth measurement |
| Phase Reference |
Keyphasor®-based timing reference |
| Thrust Monitoring |
Bearing wear and axial movement supervision |
Output Specifications
| Output TypeSpecification |
|
| Recorder Outputs |
4–20 mA proportional outputs |
| Maximum Load Resistance |
600 Ω |
| Recorder Resolution |
0.366 μA |
| Buffered Outputs |
One coaxial connector per channel |
| Buffered Signal |
Raw transducer output |
| Output Protection |
Short-circuit protected |
Alarm & Protection Functions
The 3500/72M 140734-08 supports configurable machine protection features including:
- Alert and Danger alarm levels per channel
- Latching or non-latching alarm operation
- Relay interaction through the 3500/32M relay module
- Front-panel diagnostic LEDs:
Environmental Specifications
| ItemValue |
|
| Operating Temperature |
-30°C to +65°C |
| Weight |
0.85 kg |
| Installation Method |
Rack-mounted |
| Environmental Application |
Industrial machinery protection systems |
Typical Applications
The Bently Nevada 3500/72M module is widely used in:
- Steam turbines
- Gas turbines
- Centrifugal compressors
- Reciprocating compressors
- Thrust bearing monitoring systems
- Axial shaft displacement applications
- Thermal casing expansion monitoring
FAQ
What transducers are compatible with the 3500/72M?
The module supports Bently Nevada proximity probe systems including probes, extension cables, and Proximitor® sensors in 5 mm, 8 mm, and 11 mm configurations.
Can the module monitor both static and dynamic measurements?
Yes. The monitor processes DC gap voltage for static position measurement and AC components for dynamic displacement analysis.
Is shutdown protection supported?
Yes. When integrated with a 3500/32M relay module, the system can initiate machinery shutdown logic based on configured alarm conditions.
