3500/25 149369-01 Bently Nevada Keyphasor Module

Bently Nevada 3500/25 149369-01 Enhanced Keyphasor Module

Product Introduction

The 3500/25 149369-01 from Bently Nevada delivers precise speed and phase reference measurements. This Enhanced Keyphasor Module accepts up to two transducer inputs. You can connect proximity probes or magnetic pickups. Additionally, this module provides buffered Keyphasor signals at both front and rear panels. Therefore, it serves as a critical timing reference for vibration monitoring systems.

Input Signal and Power Requirements

This module consumes only 3.2 watts under typical operation. Each 3500/25 accepts two transducer signals. The input signal range depends on your I/O module type. For non-isolated I/O modules, the range sits at +0.8 V to -21.0 V. For isolated I/O modules, the range measures +5V to -11V. Signals exceeding these ranges are internally limited. Passive magnetic pickups require shaft rotative speed above 200 rpm (3.3 Hz). The minimum input impedance reaches 21.8 kΩ.

Speed and Frequency Measurement Ranges

The 3500/25 149369-01 covers an exceptionally wide input range. You can measure from 1 to 1,200,000 cpm (0.017 to 20 kHz). This supports multiple events per revolution up to 20 kHz. The output range spans 1 to 99,999 cpm (0.017 to 1667 Hz). Such flexibility makes this module suitable for both low-speed and high-speed machinery.

Speed and Frequency Accuracy Specifications

Accuracy varies by frequency range. All values are specified at +25°C (+77°F).

Non-Processed Signals

• 0.017 to 100 Hz: ±1 cpm

• 101 to 500 Hz: ±8 cpm

• 501 to 20 kHz: ±1% of cpm

Processed Signals

• 0.017 to 60 Hz: ±1 cpm

• 61 to 150 Hz: ±8 cpm

• 151 to 20 kHz: ±1% of cpm

Auto Threshold and Manual Threshold Modes

The 3500/25 offers two triggering modes. First, Auto Threshold mode requires a minimum signal amplitude of 2 volts peak to peak. The minimum frequency in this mode is 120 rpm (2 Hz). Second, Manual Threshold mode works for any input above 0.017 Hz (1 rpm for 1 event per revolution). You can select the threshold from 0 to -20 volts dc. The minimum signal amplitude for triggering is 500 millivolts peak to peak. Additionally, hysteresis is user-selectable from 0.2 to 2.5 Volts.

Buffered Keyphasor Outputs

This module provides multiple output points. Two buffered Keyphasor outputs are available at the front of the rack via coaxial connectors. Two additional buffered Keyphasor outputs are available at the back via Euro Style connectors. The maximum buffered output impedance measures 504 Ω. Furthermore, the Keyphasor transducer power supply delivers -24 Vdc at 40 mA maximum per channel.

Front Panel LEDs and Status Indication

The front panel keeps you informed of module status. The OK LED illuminates when a fault has been detected in the Keyphasor Module. The TX/RX LED flashes when the module communicates with the Rack Interface Module (RIM). This clear indication simplifies troubleshooting.

Environmental Limits and Durability

The 3500/25 149369-01 handles harsh industrial environments. Operating temperature ranges from -30°C to +65°C (-22°F to +150°F) when used with standard Keyphasor I/O modules. However, when used with the Internal Barrier I/O module, the range becomes 0°C to +65°C (32°F to +150°F). Storage temperature extends from -40°C to +85°C (-40°F to +185°F). Humidity tolerance reaches 95%, non-condensing.

Packaging and Delivery

Packaging List

• 3500/25 149369-01 Enhanced Keyphasor Main Module (1 unit)

• Keyphasor I/O Module (sold separately, depending on termination type)

• Installation quick reference sheet

Note: No certificates or warranty documents are included in the package.

Shipping Methods
FedEx, UPS, DHL

Frequently Asked Questions

1. Can the 3500/25 149369-01 work with magnetic pickups at very low speeds?
Yes, but passive magnetic pickups require a minimum shaft speed of 200 rpm (3.3 Hz) to generate sufficient signal amplitude.

2. What happens if the input signal exceeds the voltage range?
The 3500/25 module internally limits signals exceeding the specified range. This protection prevents damage to the input circuitry.

3. How do I choose between Auto Threshold and Manual Threshold modes?
Use Auto Threshold for standard applications with clean signals above 2V peak-to-peak. Use Manual Threshold for low-amplitude signals or when you need precise trigger level control down to 500 mV peak-to-peak.

4. What is the maximum event frequency this module can track?
The 3500/25 supports up to 20 kHz input frequency. This equals 1,200,000 cpm for one event per revolution or proportionally higher for multiple events.

5. Can I access the buffered Keyphasor outputs from both the front and rear simultaneously?
Yes. Both front coaxial and rear Euro Style connectors provide active buffered outputs at the same time. This allows connection to multiple analyzers without signal degradation.