Description

The Bently Nevada 3500/33-01-CN is a 2-channel relay output module designed specifically for the Bently Nevada 3500 machinery protection system—a globally recognized platform for monitoring and safeguarding critical rotating equipment such as turbines, compressors, pumps, and generators. As a core component of API 670-compliant protection architectures, the Bently Nevada 3500/33-01-CN translates alarm and trip signals from vibration, position, or speed monitors (e.g., 3500/42, 3500/25) into hardwired relay contacts that interface directly with plant safety systems, emergency shutdown (ESD) logic solvers, or distributed control systems (DCS).

Each channel on the Bently Nevada 3500/33-01-CN features a Form C (SPDT) electromechanical relay rated for 2 A at 30 VDC, capable of driving external alarms, valve actuators, or motor contactors without intermediate relays. The module supports both independent and redundant trip configurations, enhancing system reliability in SIL 2 environments per IEC 61508. With front-panel LEDs indicating power, OK status, and individual relay activation, technicians can quickly verify operational health during routine rounds. The Bently Nevada 3500/33-01-CN is hot-swappable within the 3500 rack, minimizing downtime during maintenance or replacement—making it indispensable in continuous-process industries where unplanned outages carry significant financial and safety risks.

Technical Specifications

Main Features and Advantages

Hardwired safety for critical trip functions: Unlike software-only alarms, the Bently Nevada 3500/33-01-CN provides physically isolated relay contacts that directly interrupt power or trigger solenoid valves in emergency scenarios—ensuring fail-safe machine shutdown even if the DCS or network fails. This hardwired layer is mandated by API 670 for high-risk turbomachinery and is essential for compliance in oil & gas, power generation, and chemical plants.

Flexible configuration for diverse protection strategies: Each of the two channels on the Bently Nevada 3500/33-01-CN can be independently assigned to any alarm or trip condition from connected 3500 monitors (e.g., high vibration from 3500/42, overspeed from 3500/15). Users can configure voting logic (1oo2, 2oo2) via the 3500 Rack Interface (3500/20 or 3500/22) to implement redundancy—reducing nuisance trips while maintaining high availability. This adaptability makes the Bently Nevada 3500/33-01-CN suitable for both simple pump protection and complex multi-bearing turbine trains.

Robust industrial design with diagnostic visibility: Built for 24/7 operation in electrically noisy environments, the Bently Nevada 3500/33-01-CN uses gold-plated relay contacts and conformal-coated PCBs to resist corrosion and arcing. Front-mounted LEDs provide immediate visual feedback: green for normal operation, red for active trip—allowing operators to assess status without opening panels or connecting diagnostic tools. Its compatibility with the full 3500 ecosystem ensures seamless integration with existing machinery protection racks worldwide.

Hot-swap capability for zero-downtime maintenance: The Bently Nevada 3500/33-01-CN can be removed and replaced while the 3500 rack remains powered—a critical feature in continuous processes like LNG compression or steam turbine generation. This minimizes production loss during component failure or scheduled upgrades, while the module’s self-diagnostics report faults to the 3500 system manager for predictive maintenance planning.

Application Field

The Bently Nevada 3500/33-01-CN is a foundational element in machinery protection systems across heavy industries where equipment failure could result in catastrophic safety events, environmental releases, or millions in lost production. In natural gas processing plants, it interfaces with compressor anti-surge controllers—triggering emergency shutdowns when vibration or axial displacement exceeds safe limits. Within combined-cycle power stations, the Bently Nevada 3500/33-01-CN acts as the final trip enforcer for steam and gas turbines, cutting fuel supply or tripping breakers upon detection of bearing wear or overspeed.

In petrochemical refineries, the module drives interlocks for critical pumps handling high-temperature hydrocarbons, ensuring rapid isolation during seal failure or cavitation. Offshore platforms rely on its ATEX-certified variants to protect main propulsion and cargo transfer systems in hazardous zones. Even in renewable energy, large wind turbine OEMs integrate the Bently Nevada 3500/33-01-CN into gearbox monitoring systems to disconnect generators during abnormal vibration. Wherever API 670 standards apply—or where plant safety demands hardware-level trip assurance—the Bently Nevada 3500/33-01-CN delivers trusted, code-compliant performance.

Related Products

3500/32-01-CN: 4-channel relay module (lower current rating, 0.5 A); used for non-critical alarms.
3500/34-01-CN: 4-channel analog output module; converts vibration data to 4–20 mA for DCS trending.
3500/25: Speed/zero-speed monitor; often paired with 3500/33-01-CN for overspeed trip logic.
3500/42-01-CN: 2-channel vibration monitor; primary source of trip signals for the 3500/33-01-CN.
3500/15: Overspeed protection module with dedicated voting; can drive 3500/33-01-CN for final element actuation.
3500/20: Rack interface module; enables Modbus or Ethernet communication from the 3500 system.
3500/50: TSI Rack power supply; required for stable operation of all modules including 3500/33-01-CN.