The 3500/50 Tachometer Module serves as a 2-channel module designed to accept input from proximity probes or magnetic pickups (except as noted). It calculates shaft rotative speed, rotor acceleration, or rotor direction, compares these measurements against user-programmable alarm setpoints, and generates alarms upon violation of these setpoints. You can program the module using the 3500 Rack Configuration Software, and it offers four configuration options:

1. Speed Monitoring, Setpoint Alarming, and Speed Band Alarming.
2. Speed Monitoring, Setpoint Alarming, and Zero Speed Notification.
3. Speed Monitoring, Setpoint Alarming, and Rotor Acceleration Alarming.
4. Speed Monitoring, Setpoint Alarming, and Reverse Rotation Notification.

Application Note

It’s important to note that Bently Nevada Tachometer Modules are not intended for standalone use as speed control or overspeed protection systems. They lack the necessary redundancy and response speed for reliable operation in such applications. The analog proportional output exclusively serves data logging, chart recording, or display purposes. Speed alert setpoints are for annunciation purposes exclusively.

For the reverse rotation option, avoid using magnetic pickups since they may produce false indications of rotation direction during low speeds. Similarly, magnetic pickups aren’t recommended for the zero-speed option due to the detection circuit’s performance during low speeds.

Failure to consider these points may result in product misuse, potentially leading to property damage and/or bodily injury. In the Bently Nevada product line, an Overspeed Protection System for the 3500 System is available.

Ordering Information

• Tachometer Module: 3500/50-AXX-BXX-CXX
  • A: I/O Module Type
  • B: Agency Approval Option
  • C: Monitor Use
  • Note: Agency Approval Option B (02) is only available when Ordering Option A is 04.

Spares

• 133388-02: 3500/50 Tachometer Module   The Bently Nevada 133388-02 is a 2-channel tachometer module that measures and monitors the speed, acceleration, and direction of rotating shafts. It is used in a variety of industrial applications, including rotating machinery, power generation, and oil and gas.
• 133442-01: I/O Module with Internal Terminations
• 136703-01: Discrete Internal Barrier I/O Module with Internal Terminations
• 133434-01: I/O Module with External Terminations
• 133450-01: TMR I/O Module with External Terminations