Description
WOODWARD 8237-2596 — Overspeed Protection System Module
Product: 8237-2596 (ProTech Series Component)
Manufacturer: Woodward, Inc.
Primary Application: A critical component within the Woodward ProTech Overspeed Protection System or ProTech-GII Gas Turbine Safety System, typically serving as a digital speed detection module, voting module, or critical interface module. It is specifically designed to provide SIL 2/3 rated overspeed protection for industrial gas turbines, steam turbines, or compressors.
1. Core Overview & System Context
The Woodward 8237-2596 is a specific hardware module within the ProTech safety system family. The ProTech system is a Triple Modular Redundant (TMR) Safety Instrumented System (SIS) that operates independently of the primary turbine control system (such as a Woodward NetCon or Micronet).
Core Safety Philosophy: This module participates in implementing 2-out-of-3 (2oo3) voting logic, continuously monitoring signals from multiple independent speed sensors. Upon detection of an overspeed condition (reaching or exceeding a pre-set trip setpoint), it initiates a safety shutdown to cut off the fuel source, protecting turbomachinery from catastrophic failure.
2. Key Features & Functions
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Triple Redundant Channels: As part of the TMR architecture, this module processes signals from three independent magnetic speed sensors (MPUs), ensuring a single channel failure does not cause a nuisance trip while still allowing a safe response to a genuine hazard.
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High-Speed Digital Signal Processing: Accurately calculates shaft speed with high resolution and extremely fast response times (typically <10 ms) to meet the demanding requirements of overspeed protection.
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Diagnostics & Self-Test: Performs continuous online diagnostics to monitor internal circuit health, sensor signal integrity, and inter-channel agreement. Any faults are annunciated early to facilitate preventive maintenance.
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Safety Certification: As part of the ProTech system, its design complies with international functional safety standards such as IEC 61508, supporting safety functions up to SIL 3.
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Security Locking & Audit Trail: Modification of critical parameters (e.g., trip setpoints) typically requires a physical key or security password, and all changes are logged.
3. Common Technical Specifications (Inferred from 8237 Series)
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Speed Input: Accepts raw sine or square wave signals from three MPUs.
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Signal Conditioning: Includes filtering, amplification, and digitization.
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Processing Power: Contains a dedicated processor for speed calculation and logic voting.
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Communication Interfaces:
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Communicates with other modules within the ProTech system via a high-reliability backplane bus.
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Usually provides an RS-232/485 or Ethernet service port for status monitoring, event download, and configuration (configuration functions are typically heavily restricted and secured).
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Output: Generates a voted «Overspeed» signal to drive downstream safety relays or directly interface with the trip circuit.
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Power Supply: Requires highly reliable, redundant DC power supplies (e.g., 24 VDC).
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Physical Form Factor: A plug-in card module designed for installation in a ProTech system-specific rack or chassis.
4. System Integration & Safety Architecture
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Role: It is a critical node within the ProTech triple safety loop. Three identical 8237-2596 modules (or similar) may operate in parallel, each processing a sensor signal set, with results compared by a central voter.
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Independence: Physically and logically isolated from the primary control system, ensuring overspeed protection remains effective even if the main control system fails.
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Wiring: The three MPU sensors should be wired independently, preferably via separate routes, to avoid common cause failures.
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Testing: Supports online or offline «Overspeed Testing» functionality to verify the operation of the entire protection loop by simulating speed signals, without requiring the machine to actually overspeed.
5. Typical Applications
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Overspeed protection for industrial and aeroderivative gas turbines.
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Mechanical overspeed protection for steam turbines.
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Protection for large compressors, expanders, and other high-speed rotating equipment.
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Any application requiring overspeed protection rated up to SIL 2 or SIL 3.
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