Bently Nevada 991-25-70-01-01 Thrust Transmitter
Bently Nevada 991-25-70-01-01 Thrust Transmitter
Manufacturer: Bently Nevada
Product No.: 991-25-70-01-01
Condition:1000 in stock
Product Type: Thrust Position Transmitter
Product Origin: 8509912570014
Payment: T/T, Western Union
Weight: 820g
Shipping port: Xiamen
Warranty: 12 months
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Bently Nevada 991-25-70-01-01 Thrust Position Transmitter
The Bently Nevada 991-25-70-01-01 is a precision thrust position transmitter engineered to convert proximity probe signals into industry-standard 4-20 mA current loop outputs. This critical monitoring device enables continuous surveillance of axial rotor position in turbomachinery, providing early warning of thrust bearing degradation and preventing catastrophic equipment failures.
Technical Specifications
- Model Number: 991-25-70-01-01
- Series: 991 Thrust Transmitter
- Full Scale Range: 0.6 mm (25 mils) axial displacement
- Output Signal: 4-20 mA DC current loop (2-wire)
- System Length Options: 5 meters or 7 meters (probe + extension cable)
- Power Supply: Loop-powered from 4-20 mA receiver (12-30 VDC typical)
- Accuracy: ±1% of full scale over operating temperature range
- Response Time: <100 ms to 90% of final value
- Operating Temperature: -30°C to +65°C (-22°F to +149°F)
- Output Load: Maximum 750 Ω at 24 VDC supply
- Housing: Explosion-proof aluminum enclosure, NEMA 4X/IP66 rated
Operational Principle
The 991-25-70-01-01 thrust transmitter operates as an intelligent signal conditioner within proximity-based thrust monitoring systems:
- Dual Probe Configuration: Accepts inputs from two opposing 3300 XL 8mm proximity probes monitoring thrust collar position
- Differential Measurement: Calculates net axial displacement by subtracting probe gap voltages, eliminating thermal growth errors
- Linear Conversion: Transforms differential gap voltage into proportional 4-20 mA output (4 mA = maximum negative travel, 20 mA = maximum positive travel)
- Zero Adjustment: Field-adjustable zero point allows calibration to specific thrust bearing clearances
- Span Calibration: Factory-set for 0.6 mm full scale with ±10% field adjustment capability
Application Scenarios
The 991-25-70-01-01 thrust transmitter is essential for protecting high-value rotating equipment:
- Steam Turbines: Power generation units where thrust bearing failure can cause rotor-to-stator contact and million-dollar damage within seconds
- Gas Turbines: Aero-derivative and industrial gas turbines requiring continuous thrust position monitoring for safe operation
- Centrifugal Compressors: Process gas and air compressors where axial instability indicates impeller fouling or aerodynamic imbalance
- Turboexpanders: Cryogenic and hydrocarbon expanders operating at extreme temperatures with tight axial clearances
- Large Motors & Generators: High-speed rotating machinery where magnetic center shifts indicate bearing wear or foundation settling
- Hydro Turbines: Water turbines experiencing hydraulic thrust variations during load changes and startup/shutdown cycles
Integration with Control Systems
The 4-20 mA output enables seamless integration across diverse monitoring platforms:
- DCS Integration: Direct connection to distributed control system analog input cards for continuous trending and alarming
- PLC Compatibility: Standard current loop interface works with all major PLC brands (Allen-Bradley, Siemens, Schneider, etc.)
- SCADA Systems: Remote monitoring via RTU/PLC gateways for unmanned facilities and offshore platforms
- Machinery Protection Systems: Hardwired shutdown logic for emergency turbine trip on excessive thrust position deviation
- Vibration Monitoring Racks: Parallel connection to Bently Nevada 3500 or System 1 for comprehensive machinery diagnostics
Installation & Commissioning
Proper installation ensures accurate thrust position measurement:
- Probe Mounting: Install opposing 3300 XL 8mm probes 180° apart on thrust collar with 1.0-1.5 mm nominal gap
- Cable Routing: Use shielded extension cables; maintain 300mm separation from AC power lines to minimize electrical noise
- Wiring: Connect 4-20 mA output using twisted-pair instrumentation cable; observe polarity (+ terminal to receiver +)
- Zero Calibration: With rotor at normal operating position, adjust zero potentiometer for 12 mA output (mid-scale)
- Functional Test: Manually bump rotor axially (if possible) or simulate probe gap changes to verify output linearity
- Alarm Setpoints: Configure DCS/PLC alarms at ±0.3 mm (10 mA or 14 mA) and trip at ±0.5 mm (8 mA or 16 mA)
Diagnostic Capabilities
The 991 transmitter provides built-in fault detection:
- Probe Failure Detection: Output drives to 3.8 mA (low) or 20.5 mA (high) upon loss of probe signal, triggering immediate operator attention
- Cable Fault Indication: Open or shorted extension cables produce out-of-range outputs distinguishable from normal thrust excursions
- Power Supply Monitoring: Transmitter ceases operation below 10 VDC, preventing erroneous readings during power brownouts
- Temperature Compensation: Internal circuitry corrects for ambient temperature effects on probe sensitivity
Maintenance & Reliability
The 991-25-70-01-01 is designed for long-term reliability in harsh industrial environments:
- Calibration Interval: Annual verification recommended; typical drift <0.5% per year
- Environmental Protection: Conformal-coated electronics resist moisture, salt spray, and chemical vapors
- MTBF: >100,000 hours under normal operating conditions
- Spare Parts Strategy: Critical spare for machinery protection systems; recommend 1 spare per 10 installed units
- Obsolescence: Legacy product with ongoing factory support; compatible with modern 3300 XL proximity systems
Troubleshooting Guide
| Symptom | Probable Cause | Corrective Action |
|---|---|---|
| Output stuck at 4 mA | Probe gap too large or cable open | Check probe installation and cable continuity |
| Output stuck at 20 mA | Probe gap too small or cable shorted | Verify thrust collar clearance and cable insulation |
| Erratic output fluctuations | Electrical noise or loose connections | Inspect cable shielding and terminal tightness |
| Output drifts over time | Temperature effects or component aging | Recalibrate zero and span adjustments |
Related Products
| Product | Description | Link |
|---|---|---|
| 991-50-XX-01-00 | Bently Nevada Thrust Position Transmitter, 1.27mm (50 mil) range | View Product |
| 990-05-50-01-01 | Bently Nevada 990 Vibration Transmitter, 4-20mA output | View Product |
| 3300/20-12-01-13 | Bently Nevada Dual Thrust Position Monitor with relay outputs | View Product |
© 2025 INDUSTRIAL CONTROL HUB. All rights reserved.
Original Source: https://www.indctrlhub.com
Contact: sales@indctrlhub.com | +0086 18359243191
Product Description
Bently Nevada 991-25-70-01-01 Thrust Position Transmitter
The Bently Nevada 991-25-70-01-01 is a precision thrust position transmitter engineered to convert proximity probe signals into industry-standard 4-20 mA current loop outputs. This critical monitoring device enables continuous surveillance of axial rotor position in turbomachinery, providing early warning of thrust bearing degradation and preventing catastrophic equipment failures.
Technical Specifications
- Model Number: 991-25-70-01-01
- Series: 991 Thrust Transmitter
- Full Scale Range: 0.6 mm (25 mils) axial displacement
- Output Signal: 4-20 mA DC current loop (2-wire)
- System Length Options: 5 meters or 7 meters (probe + extension cable)
- Power Supply: Loop-powered from 4-20 mA receiver (12-30 VDC typical)
- Accuracy: ±1% of full scale over operating temperature range
- Response Time: <100 ms to 90% of final value
- Operating Temperature: -30°C to +65°C (-22°F to +149°F)
- Output Load: Maximum 750 Ω at 24 VDC supply
- Housing: Explosion-proof aluminum enclosure, NEMA 4X/IP66 rated
Operational Principle
The 991-25-70-01-01 thrust transmitter operates as an intelligent signal conditioner within proximity-based thrust monitoring systems:
- Dual Probe Configuration: Accepts inputs from two opposing 3300 XL 8mm proximity probes monitoring thrust collar position
- Differential Measurement: Calculates net axial displacement by subtracting probe gap voltages, eliminating thermal growth errors
- Linear Conversion: Transforms differential gap voltage into proportional 4-20 mA output (4 mA = maximum negative travel, 20 mA = maximum positive travel)
- Zero Adjustment: Field-adjustable zero point allows calibration to specific thrust bearing clearances
- Span Calibration: Factory-set for 0.6 mm full scale with ±10% field adjustment capability
Application Scenarios
The 991-25-70-01-01 thrust transmitter is essential for protecting high-value rotating equipment:
- Steam Turbines: Power generation units where thrust bearing failure can cause rotor-to-stator contact and million-dollar damage within seconds
- Gas Turbines: Aero-derivative and industrial gas turbines requiring continuous thrust position monitoring for safe operation
- Centrifugal Compressors: Process gas and air compressors where axial instability indicates impeller fouling or aerodynamic imbalance
- Turboexpanders: Cryogenic and hydrocarbon expanders operating at extreme temperatures with tight axial clearances
- Large Motors & Generators: High-speed rotating machinery where magnetic center shifts indicate bearing wear or foundation settling
- Hydro Turbines: Water turbines experiencing hydraulic thrust variations during load changes and startup/shutdown cycles
Integration with Control Systems
The 4-20 mA output enables seamless integration across diverse monitoring platforms:
- DCS Integration: Direct connection to distributed control system analog input cards for continuous trending and alarming
- PLC Compatibility: Standard current loop interface works with all major PLC brands (Allen-Bradley, Siemens, Schneider, etc.)
- SCADA Systems: Remote monitoring via RTU/PLC gateways for unmanned facilities and offshore platforms
- Machinery Protection Systems: Hardwired shutdown logic for emergency turbine trip on excessive thrust position deviation
- Vibration Monitoring Racks: Parallel connection to Bently Nevada 3500 or System 1 for comprehensive machinery diagnostics
Installation & Commissioning
Proper installation ensures accurate thrust position measurement:
- Probe Mounting: Install opposing 3300 XL 8mm probes 180° apart on thrust collar with 1.0-1.5 mm nominal gap
- Cable Routing: Use shielded extension cables; maintain 300mm separation from AC power lines to minimize electrical noise
- Wiring: Connect 4-20 mA output using twisted-pair instrumentation cable; observe polarity (+ terminal to receiver +)
- Zero Calibration: With rotor at normal operating position, adjust zero potentiometer for 12 mA output (mid-scale)
- Functional Test: Manually bump rotor axially (if possible) or simulate probe gap changes to verify output linearity
- Alarm Setpoints: Configure DCS/PLC alarms at ±0.3 mm (10 mA or 14 mA) and trip at ±0.5 mm (8 mA or 16 mA)
Diagnostic Capabilities
The 991 transmitter provides built-in fault detection:
- Probe Failure Detection: Output drives to 3.8 mA (low) or 20.5 mA (high) upon loss of probe signal, triggering immediate operator attention
- Cable Fault Indication: Open or shorted extension cables produce out-of-range outputs distinguishable from normal thrust excursions
- Power Supply Monitoring: Transmitter ceases operation below 10 VDC, preventing erroneous readings during power brownouts
- Temperature Compensation: Internal circuitry corrects for ambient temperature effects on probe sensitivity
Maintenance & Reliability
The 991-25-70-01-01 is designed for long-term reliability in harsh industrial environments:
- Calibration Interval: Annual verification recommended; typical drift <0.5% per year
- Environmental Protection: Conformal-coated electronics resist moisture, salt spray, and chemical vapors
- MTBF: >100,000 hours under normal operating conditions
- Spare Parts Strategy: Critical spare for machinery protection systems; recommend 1 spare per 10 installed units
- Obsolescence: Legacy product with ongoing factory support; compatible with modern 3300 XL proximity systems
Troubleshooting Guide
| Symptom | Probable Cause | Corrective Action |
|---|---|---|
| Output stuck at 4 mA | Probe gap too large or cable open | Check probe installation and cable continuity |
| Output stuck at 20 mA | Probe gap too small or cable shorted | Verify thrust collar clearance and cable insulation |
| Erratic output fluctuations | Electrical noise or loose connections | Inspect cable shielding and terminal tightness |
| Output drifts over time | Temperature effects or component aging | Recalibrate zero and span adjustments |
Related Products
| Product | Description | Link |
|---|---|---|
| 991-50-XX-01-00 | Bently Nevada Thrust Position Transmitter, 1.27mm (50 mil) range | View Product |
| 990-05-50-01-01 | Bently Nevada 990 Vibration Transmitter, 4-20mA output | View Product |
| 3300/20-12-01-13 | Bently Nevada Dual Thrust Position Monitor with relay outputs | View Product |
© 2025 INDUSTRIAL CONTROL HUB. All rights reserved.
Original Source: https://www.indctrlhub.com
Contact: sales@indctrlhub.com | +0086 18359243191