Description
Product Introduction & Engineering Value
A speed monitoring failure can leave operators blind during startup, shutdown, or emergency trip conditions. The BENTLY 3500/50-01-00 provides continuous shaft speed measurement and generates configurable alarms whenever operating limits are exceeded. It is designed for critical rotating equipment where accurate speed indication is essential.
The module accepts inputs from proximity probes or magnetic pickups and integrates directly into the BENTLY Nevada 3500 platform. In addition to speed monitoring, it supports rotor acceleration, reverse rotation detection, and zero-speed monitoring, making it suitable for turbines, compressors, pumps, and generators.
Technical Specifications
| Parameter | Specification |
|---|---|
| Manufacturer | BENTLY Nevada |
| Model | 3500/50-01-00 |
| Spare Part Number | 159434-01 |
| Product Type | 3500/50M Tachometer Module |
| Monitoring Channels | 2 |
| Sensor Inputs | Proximity Probes or Magnetic Pickups |
| Measured Parameters | Shaft Speed, Rotor Acceleration, Reverse Rotation, Zero Speed |
| I/O Module Type | Internal Terminations (-01) |
| Hazardous Area Option | None (-00) |
| Transducer Supply | 24 VDC, 40 mA maximum per channel |
| Typical Power Consumption | Approximately 5.8 W |
| Configuration Software | 3500 Rack Configuration Software |
Field Application & The “Trench” Experience
During a planned outage at a combined-cycle power plant, technicians replaced the speed sensing hardware on a steam turbine. Startup testing showed intermittent zero-speed alarms even though the magnetic pickups had been verified. Further investigation identified an aging tachometer module with unstable input conditioning.
After installing a tested 3500/50-01-00, the turbine completed its rolling sequence with stable speed indication from turning gear through full operating speed. Alarm testing confirmed proper response for overspeed warning logic and reverse rotation detection before the unit returned to service.
Typical applications include:
- Steam turbine startup speed monitoring
- Gas compressor shaft speed measurement
- Emergency diesel generator rotation monitoring
3500/50-01-00
Transparency SOP: QA & Testing
Each New Surplus or refurbished module undergoes a documented inspection procedure before shipment.
- Verify model number, hardware revision, and ordering option.
- Inspect PCB assemblies, connectors, LEDs, and front panel.
- Install the module in a compatible 3500 rack for power-up verification.
- Simulate tachometer inputs using calibrated pulse generators.
- Verify speed calculation, alarm outputs, buffered outputs, and communications.
- Package in anti-static materials with serialized inspection records.
The Veteran’s Tech Trap Guide
⚠️ This is not an overspeed protection device. The 3500/50M provides machinery speed monitoring but is not designed as a dedicated overspeed detection system. Applications requiring certified overspeed protection should use equipment specifically approved for that function.
⚠️ Verify probe type before commissioning. Incorrect configuration between magnetic pickups and proximity probes can result in unstable or missing speed readings.
PRO TIP: Always verify the number of shaft teeth or Keyphasor event configuration after replacing the module. Incorrect scaling frequently causes inaccurate RPM indications even when the hardware is functioning normally.
Dynamic FAQ
Q1. What measurements does the 3500/50-01-00 provide?
The module measures shaft rotational speed, rotor acceleration, reverse rotation, and zero-speed conditions using compatible proximity probes or magnetic pickups.
Q2. How many channels are available?
The 3500/50M provides two independent monitoring channels, allowing two speed inputs or redundant monitoring configurations.
Q3. Does the module provide Keyphasor outputs?
Yes. The module can supply conditioned Keyphasor signals to the 3500 rack backplane for use by other compatible monitoring modules.
Q4. What does the “-01-00” configuration indicate?
The suffix -01 specifies an I/O module with internal terminations, while -00 indicates no hazardous-area approval option.
Q5. Is New Surplus inventory tested?
Yes. New Surplus modules are inspected for authenticity, cosmetic condition, connector integrity, and correct operation. Refurbished units additionally undergo documented functional testing before shipment.
Q6. Is the 3500/50-01-00 compatible with all 3500 systems?
It is designed for compatible BENTLY Nevada 3500 Series racks using supported firmware and software revisions. Verify rack firmware, I/O configuration, and field wiring before installation.
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