79492-01 | Bently Nevada Temperature Monitor

Product Overview

The Bently Nevada 79492-01 is a Six-Channel Temperature Monitor module for the 3500/35 machinery protection system. This module provides real-time temperature monitoring using RTD (Resistance Temperature Detector) inputs, supporting PT100, PT500, and Ni120 sensor types. With six independent channels, high-precision measurement, and seamless integration with the 3500 system, the 79492-01 is the premier choice for critical rotating machinery temperature protection in power generation, oil & gas, and petrochemical industries.

Key Specifications

• Manufacturer: Bently Nevada (Baker Hughes)
• Product Family: 3500 Series Machinery Protection System
• Type: Six-Channel Temperature Monitor
• Module Designation: 3500/35
• Part Number: 79492-01
• Input Type: RTD (3-wire / 4-wire)
• Supported RTD Types: PT100, PT500, Ni120
• Channels: 6 independent channels
• Temperature Range: -200°C to +400°C (-328°F to +752°F)
• Accuracy: ±0.1°C (±0.2°F)
• Resolution: 0.1°C (0.2°F)
• Output Signal: 0–10 VDC
• Power Supply: 24 VDC
• Dimensions: 130 × 97 × 41 mm (5.1 × 3.8 × 1.6 in)
• Weight: 0.77 kg (1.7 lb)
• Compatibility: BENTLY 3500 System
• Safety Compliance: CE, RoHS

Features & Benefits

• Six-Channel Density: Six independent temperature channels in a single compact module reduce rack space and installation complexity compared to single-channel alternatives.
• High Precision: ±0.1°C accuracy minimizes false alarms and ensures reliable protection against thermal damage.
• Wide Sensor Support: Compatible with PT100, PT500, and Ni120 RTDs, providing flexibility for different temperature measurement requirements.
• Wide Temperature Range: -200°C to +400°C covers cryogenic applications through high-temperature industrial processes.
• 3500 System Integration: Direct integration with the 3500 Machinery Protection System enables centralized alarm management, trending, and System 1 software connectivity.
• Modular Design: Hot-swappable module design allows replacement without system shutdown (when configured for redundancy).

Typical Applications

• Bearing temperature monitoring on steam turbines and gas turbines
• Generator stator and rotor temperature surveillance
• Compressor bearing and process temperature measurement
• Motor winding and bearing temperature protection
• Pump seal and bearing temperature monitoring
• Process fluid and exhaust gas temperature tracking

Installation Guide

1. Rack Installation: Install the 79492-01 module into an available slot in the Bently Nevada 3500 monitoring system rack. The module occupies one full-height slot. Ensure the module is fully seated and the retaining screws are tightened.
2. RTD Wiring: Connect RTD sensors to the module's input terminals using 3-wire or 4-wire configuration. Follow the wiring diagram in the official Bently Nevada 3500/35 installation manual. For 3-wire RTDs, ensure all three leads are properly connected for lead resistance compensation.
3. Shield Grounding: Ground RTD cable shields at the monitoring system end only. Do not ground at both ends to prevent ground loop errors.
4. Configuration: Use the 3500 Rack Configuration Software to set:
   • RTD type per channel (PT100, PT500, Ni120)
   • Temperature range and engineering units (°C or °F)
   • Alarm setpoints (Alert and Danger)
   • Relay logic and voting configuration
   • Channel bypass and OK checking parameters
5. Calibration Verification: Apply known temperature references (e.g., ice bath at 0°C, boiling water at 100°C) to verify channel accuracy. Adjust calibration offsets if readings deviate from reference values.
6. Alarm Testing: Test alarm and relay outputs by simulating over-temperature conditions. Verify proper alarm annunciation, relay actuation, and System 1 software notification.
7. Record Keeping: Document all configuration settings, calibration data, and test results for regulatory compliance and maintenance records.

FAQ

Q: What is the difference between 79492-01 and 81228-01?
A: The 79492-01 and 81228-01 are often referenced together as they are components of the same 3500/35 temperature monitor system. The 79492-01 is the primary module part number. The 81228-01 may be an associated I/O module, terminal block, or revision variant.

Q: Can I use thermocouples with the 79492-01?
A: The 79492-01 is designed for RTD inputs (PT100, PT500, Ni120). For thermocouple inputs, use the 3500/61 temperature monitor module which supports both RTD and thermocouple sensors.

Q: What is the maximum cable length for RTD sensors?
A: RTD cable length depends on wire gauge and acceptable measurement error. As a general guideline, keep 3-wire RTD cable runs under 100 meters for best accuracy. For longer runs, use 4-wire configuration or signal conditioners.

Q: Is the 79492-01 hot-swappable?
A: The 3500 system supports hot-swappable module replacement when the rack is configured with redundant power supplies and the module is not part of a critical protection loop. Always follow Bently Nevada's hot-swap procedures to avoid system disruption.

Q: What monitoring software is compatible?
A: The 79492-01 integrates with Bently Nevada System 1 software for trending, diagnostics, and asset management. It also works with the 3500 Rack Configuration Software for module setup and the 3500 Operator Display Software for local monitoring.

Selection Tips

• Verify your monitoring system is a Bently Nevada 3500 Series rack before ordering. The 79492-01 is not compatible with 3300 series racks.
• Confirm your temperature sensors are RTD type (PT100, PT500, or Ni120). If using thermocouples, order the 3500/61 module instead.
• Determine the number of temperature points to monitor. Each 79492-01 provides 6 channels. For more than 6 points, order multiple modules.
• Verify rack space availability in your 3500 chassis. Each module occupies one full-height slot.
• When replacing a failed module, always match the exact part number (79492-01) to ensure identical functionality and connector compatibility.
• For SIL-rated safety applications, verify the module meets your required Safety Integrity Level (SIL) and consult Bently Nevada for proper system configuration.