Bently Nevada 126648-02 3500/25 | Keyphasor I/O Module

The Bently Nevada 126648-02 3500/25 isolated Keyphasor I/O module provides precise speed and phase measurement for 3500 monitoring systems. This module interfaces with proximity probes and magnetic pickups for shaft speed detection. The unit delivers galvanically isolated inputs for reliable signal acquisition in turbomachinery applications.

Technical Specifications

Parameter	Specification
Product Type	Keyphasor I/O module
Model	3500/25 (isolated)
Compatibility	Bently Nevada 3500 system
Number of Channels	4 inputs (isolated)
Input Types	Proximity probes, magnetic pickups
Input Voltage Range	-10V to -28V DC (prox probes)
Input Frequency Range	0.1 Hz to 20 kHz
Trigger Level	-1.0V to -25.6V (adjustable)
Hysteresis	0.1V to 2.5V (programmable)
Isolation Voltage	500V DC (channel-to-channel)
Signal Conditioning	Active filtering, threshold detection
Dimensions (W x H x D)	241 x 152 x 25 mm
Weight	0.8 kg
Internal Components	4 x isolation amplifiers, 1 x processor, 4 x filters, 4 x comparators
Connector Type	25-pin D-sub (female)
Terminal Type	Screw-clamp (optional adapter)
Power Supply	24V DC (from backplane)
Power Consumption	5W (typical)
Operating Temperature	-20°C to +65°C
Storage Temperature	-40°C to +85°C
Protection Class	IP20
Mounting	3500 rack (plug-in)
Approvals	CE, UL, CSA, ATEX

High-Precision Speed and Phase Measurement

The Bently Nevada 126648-02 3500/25 provides accurate speed and phase measurements for rotating machinery. This module interfaces with proximity probes and magnetic pickups for reliable data acquisition. The unit measures shaft speed from 0.1 Hz to 20 kHz. Users can monitor turbine, compressor, and generator rotational speeds precisely.

Galvanically Isolated Input Channels

Four isolated inputs provide 500V DC isolation between channels and the system. This isolation prevents ground loops and protects against electrical transients. Each input includes independent signal conditioning and threshold detection. Users can connect multiple probes without interference between channels.

Programmable Trigger and Hysteresis Settings

Users can adjust trigger levels from -1.0V to -25.6V for optimal signal detection. Programmable hysteresis from 0.1V to 2.5V eliminates noise-induced false triggering. These adjustments accommodate various probe types and installation conditions. Users can configure each channel independently for specific applications.

Advanced Signal Conditioning for Noisy Environments

Active filtering removes high-frequency noise and harmonics from probe signals. The module processes raw probe signals into clean digital pulses. Threshold detection converts analog signals into precise digital events. Users benefit from reliable speed measurements even in electrically noisy environments.

Seamless 3500 Rack Integration

The module plugs directly into the 3500 rack backplane for simple installation. A 25-pin D-sub connector provides field wiring interface for the probes. Users can replace or add modules without system shutdown. The compact half-height design fits standard 3500 rack configurations efficiently.

Wide Frequency Range for Diverse Machinery

The module covers 0.1 Hz to 20 kHz for low-speed to high-speed machinery. This range suits steam turbines, gas turbines, compressors, and generators. Users can monitor startup, run-up, and steady-state speed conditions. The module maintains accuracy across the entire frequency spectrum.