The Bently Nevada 3500/50 Tachometer Module is a highly reliable and versatile 2-channel module designed for monitoring and protecting rotating machinery. It accepts input signals from proximity probes or magnetic pickups to measure shaft rotational speed, rotor acceleration, and rotor direction. The module compares these measurements against user-programmable alarm setpoints and generates alarms when setpoints are exceeded. With its advanced configuration options, the 3500/50 Tachometer Module is an essential component for ensuring the safe and efficient operation of industrial equipment.

Key Features of the 3500/50 Tachometer Module
The 3500/50 Tachometer Module is packed with features that make it a standout choice for industrial applications:
Dual-Channel Input: Accepts up to two transducer signals from proximity probes or magnetic pickups.
Wide Input Signal Range: Operates within a range of +10.0 V to -24.0 V, with internal protection for signals exceeding this range.
Multiple Configuration Options: Can be programmed for speed monitoring, setpoint alarming, speed band alarming, zero-speed notification, rotor acceleration alarming, and reverse rotation notification.
High Accuracy: Offers a resolution of 0.3662 µA per bit with minimal error margins, ensuring precise measurements.
Recorder Outputs: Provides +4 to +20 mA recorder outputs proportional to the module’s full-scale range (rpm or rpm/min).

Applications of the 3500/50 Tachometer Module
The 3500/50 Tachometer Module is widely used in industries that rely on rotating machinery, such as:
Power Generation: Monitoring turbine speed and ensuring safe operation.
Oil and Gas: Protecting compressors, pumps, and other critical equipment.
Manufacturing: Safeguarding motors, conveyors, and other rotating assets.
Aerospace: Testing and monitoring rotor systems.
Its ability to detect reverse rotation, zero-speed conditions, and excessive acceleration makes it invaluable for preventing equipment damage and downtime.

How to Configure the 3500/50 Tachometer Module
The 3500/50 Tachometer Module is programmed using the 3500 Rack Configuration Software, which allows users to customize its operation based on specific needs. The module can be configured for:
Speed Monitoring and Setpoint Alarming: Tracks rotational speed and triggers alarms when predefined limits are exceeded.
Speed Band Alarming: Monitors speed within a specific range and alerts operators if the speed deviates.
Zero-Speed Notification: Detects when the shaft stops rotating and notifies operators.
Rotor Acceleration Alarming: Monitors rapid changes in speed and triggers alarms if acceleration exceeds safe levels.
Reverse Rotation Notification: Detects and alerts operators if the shaft rotates in the wrong direction.

Technical Specifications and Performance
The 3500/50 Tachometer Module is designed for high performance and reliability. Key specifications include:
Input Impedance: 20 kΩ (standard), 40 kΩ (TMR), or 7.15 kΩ (Internal Barrier).
Power Consumption: 5.8 Watts (typical).
Recorder Outputs: +4 to +20 mA, proportional to the module’s full-scale range.
Voltage Compliance: 0 to +12 Vdc across a load resistance of 0 to 600 Ω.
Update Rate: Approximately 100 ms, ensuring real-time monitoring.
These specifications ensure the module operates efficiently in demanding industrial environments.

Conclusion
The Bently Nevada 3500/50 Tachometer Module is a powerful and flexible solution for monitoring and protecting rotating machinery. Its advanced features, customizable configurations, and high accuracy make it an indispensable tool for industries that rely on the safe and efficient operation of critical equipment. Whether you’re monitoring turbine speed in a power plant or protecting compressors in an oil refinery, the 3500/50 Tachometer Module delivers reliable performance and peace of mind.