Bently Nevada 3500/46M 176449-06 Proximitor Seismic Monitor

3500/46M 176449-06 Bently Nevada Proximitor Seismic Monitor

Product Introduction

The Bently Nevada 3500/46M 176449-06 is a versatile four-channel monitor engineered specifically for hydroelectric machinery protection. This module accepts inputs from proximity probes, seismic transducers, dynamic pressure sensors, and air gap sensors. It conditions these signals to deliver accurate vibration, position, and static/dynamic pressure measurements. The 3500/46M then compares these conditioned signals against user-configurable alarm setpoints. For Hydro Radial Vibration channels, it combines shaft gap movement with NX amplitude to detect shear-pin failures effectively. Configuration is accomplished through the 3500 Rack Configuration Software, offering tremendous flexibility for various monitoring applications.

Supported Monitoring Functions

The Bently Nevada 3500/46M 176449-06 supports an extensive range of monitoring modes. Users can configure it to perform Hydro Radial Vibration, Hydro Air Gap, Hydro Velocity, Hydro Acceleration, and Hydro Thrust measurements. Additionally, it offers Multimode versions of these functions, plus Multimode Hydro Dynamic Pressure and Hydro Stator End Winding (SEW) monitoring. This broad capability makes the 3500/46M suitable for complete hydro-generator protection schemes.

Input Specifications

This monitor accepts signals from one to four sensors simultaneously. Input impedance varies by sensor type: 10 kΩ for Prox/Accel inputs, and 3.5 MΩ for Velomitor sensors. The multimode positive input I/O presents a 50 kΩ impedance. Sensitivity settings are function-dependent and field-selectable. For Hydro Radial Vibration, options include 0.79 mV/μm, 3.94 mV/μm, or 7.87 mV/μm. Air Gap monitoring supports 0.20 mV/μm, 0.22 mV/μm, 0.49 mV/μm, or 0.55 mV/μm. Velocity mode uses 20 mV/mm/s, while Thrust offers 3.94 mV/μm, 7.87 mV/μm, or 11.22 mV/μm. Acceleration ranges from 1.02 mV/m/s² to 10.19 mV/m/s² for SEW applications.

Outputs and Indicators

The front panel of the 3500/46M 176449-06 includes three critical status LEDs. The OK LED confirms proper module operation. The TX/RX LED indicates active communication with other modules in the 3500 rack. Meanwhile, the Bypass LED illuminates when the monitor is in Bypass Mode. Each channel features a buffered transducer output via coaxial connectors on the front panel. These connectors are short-circuit protected and present a 550 Ω output impedance. The recorder outputs deliver +4 to +20 mA, proportional to full-scale measurements, with a resolution of 0.3662 µA per bit and an update rate of 100 ms or less.

Transducer Power Supply

The 3500/46M 176449-06 provides regulated power for connected transducers. For Prox/Velom I/O and Multimode Prox/Velom I/O, it supplies -23 Vdc nominal at up to 43 mA. The Multimode Positive Input I/O delivers +23 Vdc nominal at 23 mA maximum. This integrated power capability simplifies system wiring and reduces external power supply requirements.

Frequency Response and Accuracy

Signal conditioning performance varies by monitoring function. For Hydro Radial Vibration, the direct filter response spans 0.104 Hz to 500 Hz, covering rotor speeds from 25 to 1,500 cpm. The 1X and NX vector filters employ constant Q design with minimum stopband rejection of -50 dB. Accuracy for direct and gap measurements is within ±0.33% of full-scale typically, with ±1% maximum.

Hydro Velocity offers two frequency modes. Low Mode covers 0.1875 to 343.75 Hz, while High Mode extends to 0.75 to 1375 Hz. The 1X and 2X vector filters provide -51 dB minimum stopband rejection. Direct measurement accuracy reaches ±1% of full-scale typically, ±2% maximum.

For Hydro Thrust, the direct filter has a -3dB point at 1.2 Hz, with gap filtering at 0.41 Hz. Accuracy is excellent at ±0.33% of full-scale typical, ±1% maximum.

The Hydro SEW function monitors 2x line frequency (100 Hz or 120 Hz) using a constant Q filter with -60 dB stopband rejection. Direct and bias voltage accuracy is ±1% of full-scale maximum.

Physical Specifications

The main board of the 3500/46M 176449-06 measures 241.3 mm x 24.4 mm x 241.8 mm (9.50 in x 0.96 in x 9.52 in) and weighs 0.91 kg (2.0 lb). The associated I/O modules are smaller, measuring 241.3 mm x 24.4 mm x 99.1 mm (9.50 in x 0.96 in x 3.90 in) and weighing just 0.20 kg (0.44 lb). This modular design allows flexible placement within the 3500 rack system.

Environmental Limits

The 3500/46M 176449-06 operates reliably across a wide temperature range. Operating temperatures span from -30 °C to +65 °C (-22 °F to +150 °F). Storage temperatures extend from -40 °C to +85 °C (-40 °F to +185 °F). It supports humidity levels up to 95%, non-condensing. No minimum rack load is required.

Installation Guidelines

Installing the Bently Nevada 3500/46M 176449-06 requires careful attention to slot allocation. First, power down the rack system completely. Next, select the appropriate slot for both the main monitor board and its associated I/O module. Insert the main board first, ensuring it seats firmly against the backplane connector. Then, install the I/O module in its designated position. After securing both modules with retaining screws, restore power. Finally, use the 3500 Rack Configuration Software to configure the desired monitoring functions and alarm setpoints. Verify normal operation by checking that the OK LED illuminates steadily.

Packaging List

• Bently Nevada 3500/46M 176449-06 Main Monitor Board (1 unit)

• Associated I/O Module (1 unit)

• Retaining screws (2 sets)

• Configuration guide

Frequently Asked Questions (FAQ)

1. What types of sensors can connect to the 3500/46M 176449-06?
This monitor accepts proximity probes, seismic transducers (Velomitor), dynamic pressure sensors, and air gap sensors. It supports up to four inputs simultaneously.

2. Can the 3500/46M detect shear-pin failures?
Yes, the Hydro Radial Vibration function combines shaft gap movement with NX amplitude to provide specific alarming for shear-pin failure detection.

3. What is the difference between standard and Multimode functions?
Multimode functions allow each channel to be configured independently for different measurement types. Standard modes apply the same measurement type across all channels.

4. How do I configure the 3500/46M 176449-06?
Configuration is performed using the 3500 Rack Configuration Software, which runs on a connected PC. This software allows you to select monitoring functions, set alarm thresholds, and adjust sensitivity parameters.

5. What does the Bypass LED indicate?
The Bypass LED illuminates when the monitor is in Bypass Mode. In this state, the module is logically removed from the rack's protection system, allowing maintenance without triggering false alarms.

6. What shipping carriers do you use?
We ship all orders via Fedex, UPS, or DHL with full tracking and insurance for every shipment.