Product Overview

The Bently Nevada 125792-01 is a high-precision Enhanced Keyphasor Module engineered for the 3500 Series machinery protection system. This half-height, dual-channel component is fundamental for acquiring phase reference signals and rotative speed measurements from a wide variety of transducers. By processing pulses from proximity probes or magnetic pickups, the 125792-01 provides the critical timing information required to calculate vector parameters, such as 1X vibration amplitude and phase lag. It acts as the system's temporal anchor, ensuring that all vibration data across the rack is accurately synchronized with the shaft's rotational position, which is essential for advanced machinery diagnostics and multi-plane balancing.

Engineering Parameters and Hardware Metrics

• Signal Processing Supports two independent Keyphasor channels

• Input Source Compatibility Proximitor sensors, Magnetic Pickups, or Optical transducers

• Frequency Signal Accuracy High-fidelity performance at ±0.05%

• Speed Resolution Precise 0.1 RPM increments

• Sampling Frequency 1000 Hz high-speed data acquisition

• Electrical Demand 3.2 Watts (Typical)

• Analog Transmission 4-20mA proportional output signals

• Environmental Tolerance -40°C to +85°C Operating Temperature

• Atmospheric Resistance 0 to 100% Relative Humidity (non-condensing)

• Unit Mass 0.34 kg (0.76 lbs)

• Physical Dimensions 119.9 mm x 24.4 mm x 256.5 mm

• Manufacturing Origin USA

Site Deployment and Industrial Utility

The 125792-01 is a staple in power generation and heavy industrial facilities where synchronous vibration analysis of large turbines and compressors is required. In these environments, knowing the exact position of the shaft at any given microsecond is the difference between a successful startup and a catastrophic trip. The module provides "once-per-turn" timing pulses that are utilized by other 3500 monitoring modules to filter vibration signals and determine specific machine health characteristics like unbalance or misalignment. Its ruggedized design allows for deployment in extreme temperatures, making it a reliable choice for remote turbine enclosures or offshore platforms. Whether used for simple speed monitoring or as part of a complex condition monitoring network, the Enhanced Keyphasor Module ensures the integrity of the safety loop by providing millisecond-perfect timing data.

FAQ

Q: What is the primary function of the 125792-01 in a 3500 rack?

A: It provides a phase reference signal (the Keyphasor) that allows the system to relate vibration signals to a specific point on the rotating shaft, which is necessary for calculating phase and filtered 1X vibration.

Q: Can this module accept inputs from magnetic pickups and proximity probes simultaneously?

A: Yes, the 125792-01 is designed to receive and process signals from various transducer types including proximity probes and magnetic pickups to determine shaft speed and orientation.

Q: Is this module considered a full-size or half-size module?

A: This is a half-height module, which means it occupies one-half of a standard slot in the 3500 chassis, typically allowing for two such modules to be stacked in a single rack slot.

Q: Does the 125792-01 provide a 4-20mA output for speed?

A: Yes, the module can be configured to provide a 4-20mA analog signal representing the measured rotative speed for integration with a DCS or PLC.

Q: What happens if the Keyphasor signal is lost?

A: If the signal is lost, modules relying on the phase reference for filtered measurements (like 1X amplitude) will enter an error state or provide non-filtered data, though the rack's primary safety protection often remains active.