Bently Nevada 3500/44-01 – Aeroderivative Gas Turbine Vibration Monitor for the 3500 Series Rack

The Bently Nevada 3500/44-01 is a dedicated four-channel vibration monitor tailored for aeroderivative gas turbine (AGT) applications within the 3500 machinery protection platform.    It typically handles proximity probe and seismic sensor inputs, delivering reliable protection measurements and API-style alarm logic for high-speed rotating equipment.    From my experience, it fits best where you need continuous, rack-level protection and clean buffered outputs for diagnostics.

• Four independent channels – supports typical AGT measurement points (e.g., radial vibration, casing acceleration/velocity), enabling consolidated protection in one slot.

• Proximity and seismic inputs – accepts Bently Nevada proximity probes and common accelerometers/velocity transducers, giving flexibility across turbine frames.

• Alert/Danger alarms with latched logic – standard two-level protection practice for trip integration and plant interlocks.

• Buffered transducer outputs – front access for portable data collectors and route-based analysis, which seems to be essential during startup tuning.

• Keyphasor tracking (with 3500/25) – enables 1X, 2X and order-based measurements that are common on high-speed aero-derivative units.

• Rack-integrated communications – data and status available through the 3500/22M TDI for Modbus/TCP and System 1 connectivity in most cases.

• Designed for continuous, online protection – no PC required for protection functions; configuration via rack tools and standard procedures.

Built for aeroderivative gas turbines used in power generation, oil & gas compression trains, and fast-start peaker units. You might notice that it’s especially helpful where high rotor speeds and rapid load swings make order tracking and reliable alarms non-negotiable.    In many cases we see it deployed alongside 3500/25 Keyphasor and 3300XL proximity probes for shaft vibration, plus accelerometers on turbine casings and accessory gearboxes.

• Combined-cycle plants using LM-series aero-derivative turbines

• Offshore and onshore gas compression skids with quick-ramp requirements

• Peaking stations and mobile power units needing compact, rack-based protection

• Cogeneration and industrial process drives where continuous vibration protection is standard practice

• Reliability you can audit – alert/danger logic and event logging tie cleanly into plant trips and ESD strategies.

• Compatibility across the rack – leverages standard 3500 infrastructure and works with System 1 for diagnostics, which typically cuts commissioning time.

• Procurement-friendly – shared spares and common I/O practices across the 3500 family help reduce stocking complexity and cost.

• Service and lifecycle support – mature platform with well-documented procedures; firmware and configuration tools are standard across the fleet.

A maintenance lead at a CCGT site told us their switch to the 3500/44 channels on accessory gearboxes “cleaned up our starts” because the buffered outputs made it easier to trend 1X during overspeed tests. That’s pretty typical feedback we hear.

• Panel/Rack requirements – install in a standard 3500 rack with adequate cabinet ventilation; keep ambient within specified limits and away from vibration hotspots.

• Wiring practices – route transducer cables separately from power runs; maintain shield continuity; follow proximity probe extension and calibration guidelines.

• Safety – implement proper lockout/tagout and trip bypass procedures when commissioning; verify alert/danger setpoints before enabling trips.

• Routine care – periodically verify sensor health (gap voltages for proximities, bias checks for accelerometers); clean front connectors; back up configuration; apply firmware updates when validated for your rack revision.

• Calibration – perform channel verification with a signal source and compare to buffered outputs; re-validate following any probe replacement or shaft work.

The 3500 platform is generally supplied with CE marking and UL/cUL listing, and in many cases includes Zone 2 / Class I, Div 2 approvals when configured appropriately.    RoHS conformity is commonly cited for current production variants, but exact approvals can vary by module and rack revision. Standard manufacturer warranty applies to new hardware; support and repair options are available for installed bases.

• 3500/25 Keyphasor Module – speed and phase reference for order tracking

• 3500/22M TDI – rack communications (Modbus/TCP, System 1 data integration)

• 3300XL Proximitor and Probes – shaft vibration and position measurements

• 330400/330425 Accelerometers and 330500 Velocity Sensors – casing measurements on turbine and gearboxes

Note: Specifications above reflect typical use of the 3500/44-01 within a standard 3500 rack. For exact approvals, firmware compatibility, and the meaning of the “-01” build option as applied to your I/O type, please match against your rack BOM and site standards.