Bently Nevada 3500/32 (125712-01) – 4-Channel Relay Module for 3500 Machinery Protection Racks

The Bently Nevada 3500/32 4‑Channel Relay Module ties your protection logic to hardwired trips and alarms. It listens to alarms from any monitor in the rack—Alert, Danger, Not OK—and drives four independent dry-contact relays based on flexible logic. From my experience, plants choose the 3500/32 when they want simple, dependable trip paths with voting, latching, and fail‑safe behavior, without adding extra relays in the cabinet. Part number 125712-01 refers to a common hardware/I/O variant used widely across turbine, compressor, and pump applications.

Key Features

• Four dry-contact relays: Independent outputs for trips, alarms, or interlocks—mapped from any monitor channel in the rack.
• Programmable logic: Voting (e.g., 2‑out‑of‑3), latching/non‑latching, time delays, and bypass options to match site trip philosophy.
• Fail‑safe configuration: Normally Energized or Normally De‑energized operation to align with safety standards in most plants.
• Backplane integration: No sensor wiring to the module; it listens to alarm conditions over the 3500 rack backplane.
• Clean cabinet design: One thing I appreciate is how it reduces interposing relays and hand‑built logic, cutting wiring effort and potential points of failure.
• Event traceability: Relay actions are tied to monitor alarms and timestamps, which typically shortens post‑trip investigations.

Technical Specifications

Application Fields

You might notice the 3500/32 shows up wherever a clean, deterministic trip path is required:

• Gas and steam turbines: overspeed, high vibration, and bearing temperature trip outputs
• Compressors and expanders: Danger alarms driving ESD systems or fuel shutoff valves
• Refining and petrochemical units: hardwired trips to DCS/PLC interlock matrices
• Balance‑of‑plant equipment: fans, blowers, and critical pumps requiring local alarm/trip relays

Advantages & Value

• Reliability first: Fail‑safe relay options and simple wiring reduce nuisance trips and common‑cause faults.
• Seamless compatibility: Natively maps alarms from any 3500 monitor—no external logic blocks needed in many cases.
• Lower installed cost: Fewer interposing relays and less panel wiring typically mean faster projects and easier FAT/SAT.
• Maintainability: Clear status in the rack and straightforward proof‑testing make it friendly for operations.
• Fleet standardization: Common hardware across machines simplifies spares and training.

Installation & Maintenance

• Cabinet & environment: Mount the 3500 rack in a clean, ventilated enclosure; avoid corrosive atmospheres and condensation.
• Wiring practices: Use the rear I/O terminal for dry contacts; route wiring away from high‑noise power; keep runs short where practical.
• Contact loads: Drive low‑energy control circuits; for higher loads, use an interposing relay—this tends to preserve contact life.
• Safety & handling: De‑energize the rack before inserting/removing modules; follow ESD precautions to protect connectors.
• Logic setup: Configure voting, latching, and delays to match the site trip matrix; many teams also document a proof‑test procedure per relay.
• Routine checks: Function‑test relays during scheduled outages, back up configuration, and review alarm/event logs for clarity.

Quality & Certifications

• CE marking for EMC and safety (module family)
• UL/cUL and CSA certifications commonly available for 3500 rack modules
• RoHS conformity where applicable
• Manufacturer’s standard warranty is typically 12 months; we support a 365‑day warranty on supply