Frequently Asked Questions
Q1: What is the Bently Nevada 3500/50E?
A1: The 3500/50E is a 2-channel tachometer module in the Bently Nevada 3500 system. In practice, it’s used to pick up pulse signals from proximity probes or magnetic pickups and turn them into shaft speed data. It covers things like rotative speed, rotor acceleration, and direction. Once something looks off, it triggers alarms for machinery protection before damage escalates.
Q2: What sensors can the 3500/50E work with?
A2: It works with standard eddy current proximity systems like 3300 XL 8mm, and also magnetic pickups. Input range is roughly +10V to -24V. For hazardous areas, you can go with versions that include internal barriers, so external isolators are usually not needed.
Q3: What are the measurement range and tracking accuracy specifications of the 3500/50E?
A3: Speed range is quite wide, from 0.1 RPM up to 99,999 RPM, with input frequency up to 20 kHz. Accuracy depends on speed: below 100 RPM is about ±0.1 RPM, 100–10,000 RPM around ±1 RPM, and above 10,000 RPM it stays within roughly ±0.01%.
Q4: What outputs does the 3500/50E support?
A4: It provides two 4–20 mA outputs for DCS or ESD integration. There are also buffered outputs on the front panel for handheld diagnostic tools. On the system side, data is sent through the 3500 rack TDI module to System 1 for monitoring.
Q5: Can the 3500/50E be used for overspeed shutdown?
A5: Not. The 3500/50E is fine for speed alarms, reverse rotation, and zero speed detection, but it’s not designed for safety trip functions. With about 100 ms response time, it doesn’t meet API 670 requirements. For overspeed protection, the 3500/53 module is the correct choice.
Q6: How is the 3500/50E configured?
A6: Configuration is done through the 3500/01 rack software. It can be set into different modes like Speed Monitoring, Speed + Acceleration, Speed + Reverse Rotation, or Reverse Rotation only. There’s also a peak hold option to store max speed or reverse events for later review.