Description
Product Introduction & Engineering Value
Speed is one of the most basic yet critical parameters on any rotating machine. The Bently Nevada 3500/50 133388-02 gives you accurate overspeed, underspeed, and reverse rotation detection in a compact two-channel package. It can also supply conditioned Keyphasor signals to the rest of the rack, often eliminating the need for a separate Keyphasor module.
Programmable setpoints and multiple operating modes make this module adaptable to everything from simple speed alarming to advanced acceleration monitoring during startups.
Technical Specifications
Inputs
- Two channels accepting proximity probes or magnetic pickups
- Wide input voltage range with internal limiting
Outputs & Features
- Programmable alarms for overspeed, acceleration, and reverse rotation
- Buffered transducer outputs
- Peak hold function for maximum speed or reverse events
Environmental
- Operating Temperature: -30°C to +65°C
- Power Consumption: Low draw from rack backplane
Physical
- Full-height module for standard 3500 rack slots
Field Application & The “Trench” Experience
A paper mill had recurring issues with undetected reverse rotation on a large induced draft fan during power dips. After installing the 133388-02 and enabling reverse rotation alarming, the system caught a brief reverse event during the next outage and prevented potential gear damage. Maintenance was able to inspect and correct the issue before restarting.
Niche Applications
- Overspeed protection on steam turbine generators
- Reverse rotation detection on centrifugal pumps and fans
- Acceleration monitoring during gas compressor startups
- 3500/50 133388-02
- 3500/50 133388-02
Transparency SOP: QA & Testing
Each 133388-02 undergoes signal injection testing with calibrated pulse generators to verify accurate speed measurement, alarm setpoint triggering, and reverse rotation logic across the full operating range. Buffered outputs and Keyphasor passthrough get confirmed before the module receives final approval and documentation.
The Veteran’s Tech Trap Guide
⚠️ Transducer Selection — Magnetic pickups require sufficient shaft speed to generate reliable signals. Proximity probes are better for low-speed or zero-speed detection.
PRO TIP: Use the peak hold reset function after maintenance to clear old maximum values.
⚠️ Keyphasor Sharing — When using this module to supply Keyphasor signals to other monitors, confirm proper configuration to avoid phase reference errors.
Dynamic FAQ
Q: How many speed channels does the 3500/50 provide? A: Two independent channels per module.
Q: Does it support reverse rotation detection? A: Yes, one of the available configuration modes focuses on reverse rotation monitoring.
Q: Can this module provide Keyphasor signals to the rack? A: Yes, it can supply conditioned Keyphasor signals to other monitors.
Q: What warranty applies to New Surplus units? A: One-year warranty on all 133388-02 modules.
Q: Is the module hot-swappable? A: Yes, standard for 3500 series components.
Q: What input devices work best with this tachometer? A: Proximity probes for most applications or magnetic pickups where appropriate for the speed range.
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