Description
The Woodward 6410-024-N-N-N is a specialized ProTech-GII (Generation II) safety system designed for high-speed overspeed protection of steam turbines, gas turbines, and reciprocating engines. This specific configuration is a Simplex (non-redundant) model, engineered to provide a dedicated, high-reliability safety trip function. It monitors turbine shaft speed via magnetic pickups (MPUs) or proximity probes and initiates a hardware-based shutdown sequence within milliseconds if an overspeed condition or a “rate-of-acceleration” limit is exceeded.
Commercial and Availability Status
- Condition: New Original (Factory Sealed Surplus)
- Warranty: 12-Month Mechanical and Electrical Warranty
- Availability: In Stock
- Lead Time: Ships within 1 to 2 business days
- Pricing Note: Price is subject to market conditions and regional demand. Contact our technical sales office for a formal, itemized quote.
Technical Specifications
| Parameter | Specification / Value |
| Model Number | 6410-024-N-N-N |
| Protection Type | Simplex (Single Channel) |
| Power Input | 18 to 32 V DC (Dual redundant inputs) |
| Speed Inputs | 2 MPU or Proximity Probe inputs |
| Speed Range | 0.5 Hz to 30 kHz |
| Accuracy | 0.01% of setpoint |
| Response Time | < 40 milliseconds (typical) |
| Relay Outputs | 2 Form C (SPDT) Trip Relays, 1 Alarm Relay |
| Analog Output | 1 programmable 4–20 mA (for speed readout) |
| Communication | RS-232 / RS-485 (Modbus RTU) |
| Enclosure Rating | IP56 (Dust-tight, protection against powerful water jets) |
| Operating Temp | −20 to +60 °C (−4 to +140 °F) |
Part Number Breakdown (6410-024-N-N-N)
Understanding the Woodward nomenclature is critical for ensuring hardware compatibility with existing field installations:
- 6410-024: Base model designation for the ProTech-GII Simplex Overspeed Protection unit.
- -N (First): Standard Mounting (Panel Mount/Flush Mount).
- -N (Second): Standard Housing (No special environmental coatings or custom labels).
- -N (Third): Standard Configuration (Factory default I/O and protocol settings).
Technical Features and Protection Logic
The 6410-024-N-N-N is not a standard PLC; it is a purpose-built safety instrument. It utilizes high-speed internal logic to evaluate speed signals without the overhead of a general-purpose operating system, ensuring deterministic trip times.
Dual Speed Sensing
The unit accepts two independent speed inputs. In its standard logic, it can be configured to trip based on either input (1oo2) or require both for high-integrity sensing. This protects the turbine from a “lost signal” scenario where a single sensor failure could otherwise prevent a safety trip.
Rate-of-Acceleration Trip
In addition to the static overspeed setpoint, the ProTech-GII monitors how fast the turbine is accelerating. If the rate of change (dR/dt) exceeds the programmed threshold, the unit initiates a trip before the turbine even reaches the overspeed limit. This is vital for decoupled turbine scenarios where the rotor may accelerate faster than a standard governor can respond.
Engineering and Field Deployment Guidelines
1. Speed Sensor Gap Alignment
For the 6410-024 to function reliably, the magnetic pickups (MPUs) must be gapped correctly to the gear tooth.
Expert Field Note: A weak signal (below 1.0 Vrms at low speed) will trigger a “Loss of Speed” alarm. Ensure the MPU gap is set such that the voltage at cranking speed is at least 1.5 Vrms, but does not exceed 25 Vrms at maximum rated speed to avoid clipping the input circuitry.
2. Trip Test Functionality
The ProTech-GII includes an integrated “Trip Test” feature that allows operators to simulate an overspeed condition without overspeeding the actual turbine.
- The unit injects a frequency internally to verify the trip relays cycle correctly.
- This test should be performed during every scheduled start-up sequence to verify the integrity of the interposing relay and solenoid path.
3. Modbus Integration
While the 6410-024-N-N-N is a standalone safety device, the Modbus RTU port should be utilized to mirror the speed data and alarm status to the primary DCS (Distributed Control System). This allows the plant operator to see why a trip occurred (e.g., distinguishing between an actual overspeed event and a speed sensor failure).
Frequently Asked Questions
Can I use the 6410-024-N-N-N for a SIL-rated safety application?
Yes, the ProTech-GII series is designed for use in safety-related systems. While the Simplex version provides robust protection, many SIL 2 or SIL 3 architectures require the Voted (TMR) version of the ProTech-GII (e.g., the 8237-series) which uses three independent modules in a 2oo3 configuration. Always check your site-specific Safety Requirement Specification (SRS).
What happens if the unit loses one of its two 24 V DC power feeds?
The unit features dual redundant power input terminals. If one power source fails, the unit will continue to operate without interruption on the secondary feed, though it will typically trigger a “Power Supply Fault” alarm via the Modbus or alarm relay.
How is the unit programmed?
Configuration is performed via the front-panel keypad and the multi-line vacuum fluorescent display (VFD). No external proprietary software is required for the basic overspeed and acceleration setpoints, making it easy to commission in remote field environments.
