BENTLY 330180-91-05 Preamplifier for Proximity Monitoring

The BENTLY 330180-91-05 is a preamplifier (often used as a Proximitor-style driver) designed to condition eddy-current proximity probe signals for reliable shaft vibration and position measurements. It’s typically paired with BENTLY proximity probes and extension cables to form a complete 3300-series style sensing chain. From my experience, this model is favored in rotating machinery protection where stability and noise immunity matter.

Use it in compressors, turbines, fans, or critical pumps where continuous monitoring is expected. It seems to be a good fit for retrofit projects too, especially when existing probes and cables need a compatible, well-behaved driver.

• Proximity probe signal conditioning – Accepts BENTLY eddy-current probes and delivers both gap (DC) and dynamic (AC) vibration signals to your monitor or PLC.

• Stable linear response – Calibrated to deliver consistent µm/mil-per-volt scaling across the specified measurement range, which helps with repeatable balancing and diagnostics.

• Rugged, potted construction – Built to handle industrial environments; typically resists oil mist, humidity, and electrical noise near large motors and VFDs.

• Low power, negative supply operation – Runs on a nominal -24 Vdc supply from the monitoring system; low current draw to simplify cabinet power budgeting.

• Compatible sensing chain – Works with typical BENTLY probe and extension cable combinations (for example 3300/3300 XL families) when option codes match the calibration set.

• Shielding and grounding provisions – Designed for single-point grounding to minimize ground loops and maintain clean spectra in most cases.

• Easy mounting – Compact body for panel/bulkhead mounting close to the machine casing to keep cable lengths within spec.

This preamplifier is used widely on rotating assets where displacement-based vibration data is critical:

• Steam and gas turbines – shaft relative vibration, axial position (thrust), and startup transient tracking

• Compressors and expanders – surge investigations and bearing health trending

• Large motors, generators, and fans – monitoring unbalance, rubs, and misalignment events

• API 610/617 pumps – protection against dry-run or mechanical contact through displacement signals

One maintenance manager told us their signal quality “cleaned up” after standardizing on this driver, especially around VFD harmonics. That’s a small remark, but it tends to track with what we see in the field.

• Reliability – Robust electronics and potting reduce nuisance trips and drift over time.

• Compatibility – Works with established BENTLY probe and cable ecosystems; makes retrofits straightforward in many cases.

• Lifecycle cost – Stable calibration and long service intervals can reduce technician hours and unexpected callouts.

• Supportability – Clear wiring and standard gap/dynamic outputs simplify hookup to protection systems and historians.

• Mounting – Install on a rigid, grounded panel close to the probe location to respect cable length specs. Avoid mounting near high-current busbars.

• Cabinet & ventilation – Use an IP-rated enclosure suitable for the environment; allow air space to keep the module within its temperature range.

• Wiring – Follow single-point grounding; use shielded cable; route separately from power cables and VFD outputs. Verify polarity on -24 Vdc supply.

• Calibration check – Periodically verify gap voltage and scale factor with a micrometer or calibrated target, typically during turnaround windows.

• Routine care – Inspect connectors, clean terminals, and confirm stable baseline spectra. Firmware isn’t applicable; keep records of probe-driver-cable option codes.

• Manufactured under ISO 9001 quality systems

• CE and RoHS compliance for industrial environments (model and region dependent)

• UL/cUL recognition may apply to select configurations

• Standard manufacturer’s warranty typically 1 year; extended options available through authorized channels

• BENTLY proximity probes (e.g., 3300/3300 XL 5 mm or 8 mm types, depending on calibration set)

• BENTLY extension cables (length and option codes matched to probe and driver, to maintain factory calibration)

• Condition monitoring systems and protection racks expecting gap/dynamic voltage inputs

If you need help verifying that 330180-91-05 matches your existing probe and cable option codes, share your current BOM or photos of the nameplates. You might notice that small option differences matter for exact scale factor and linear range, and it’s quicker to confirm upfront.