Key Technical Specifications

• Product Model: 3500/25 149369-01
• Manufacturer: Bently Nevada
• Associated System: 3500 Machinery Protection System
• Module Type: Enhanced Keyphasor Module (Half-height, Dual-channel)
• Sensor Compatibility: Proximity probes or Magnetic pickups
• System Capacity: Up to 4 Keyphasor signals (Normal) / Up to 8 (Paired configuration)
• Output: Buffered Keyphasor signals via front coaxial and rear Euro connectors
• Output Impedance: Maximum 504 Ohms
• Sensor Power: -24 Vdc, up to 40 mA per channel
• Operating Temperature: -30°C to +65°C (Non-barrier I/O)

Core Performance and Selection Advantages

The BENTLY 3500/25 149369-01 is an enhanced Keyphasor module specifically engineered to serve as the timing heartbeat for the 3500 Machinery Protection System. Its primary role is to detect when a keyphasor mark on a rotating shaft aligns with the sensor, converting this into a precise digital pulse. This allows 3500 monitor modules and external diagnostic tools to accurately measure shaft speed and vector parameters, such as 1X vibration amplitude and phase. Selecting this module provides superior signal processing capabilities compared to older designs, ensuring reliable operation even in challenging industrial environments.A major selection advantage is its robust redundancy and capacity. In standard configurations, a 3500 rack can accept up to four Keyphasor signals. However, for systems requiring higher channel density or Triple Modular Redundancy (TMR), the 3500/25 supports paired configurations, allowing the system to accept up to eight signals. In TMR applications, two modules operate in parallel to provide primary and secondary keyphasor signals, guaranteeing uninterrupted protection. Furthermore, this module is a direct, drop-in replacement for the legacy PWA 125792-01, offering enhanced performance while maintaining complete backward compatibility in form, fit, and function.From a total cost of ownership perspective, the 3500/25 offers enhanced product functionalities that streamline maintenance and data management. It features the ability to generate once-per-revolution event signals from multi-event inputs, reducing the need for external signal conditioning. Additionally, it supports field-upgradable firmware and provides comprehensive asset management data reporting. These intelligent features reduce engineering overhead and enable predictive maintenance, making it a highly cost-effective choice for modernizing or expanding critical machinery protection systems.

System Integration and Expandability

Integrating the 3500/25 149369-01 into a broader automation architecture is highly streamlined. The module slots directly into the 3500 rack backplane, communicating seamlessly with monitor modules (such as the 3500/42M) and the 3500/22M Transient Data Interface. For system configuration and data extraction, it integrates natively with the 3500 Rack Configuration software and System 1 predictive maintenance platforms. The buffered keyphasor outputs available on both the front and rear of the module allow for easy daisy-chaining to external data acquisition systems, PLCs, or DCS interfaces without degrading the signal.The expandability of the 3500/25 is designed to accommodate complex, multi-machine trains. When configuring systems with more than four keyphasor inputs, engineers can utilize the paired configuration, which requires two consecutive monitoring positions (e.g., upper and lower half-slots). This allows four Keyphasor modules to provide four output channels while accepting four primary and four backup input channels. For specialized applications requiring electrical isolation from external control systems, isolated Keyphasor I/O modules are also available within the same ecosystem. This modular flexibility ensures that whether you are building a single-compressor skid or a multi-turbine power generation facility, the 3500/25 scales perfectly to meet your exact architectural requirements.