Woodward ProTech 203 | Overspeed Protection System 9905-998

The Woodward ProTech 203 (P/N 9905-998) is a high-reliability, triple-modular redundant (TMR) electronic overspeed protection system. Designed specifically for critical rotating machinery such as steam, gas, and hydro turbines, it provides essential protection against catastrophic overspeed events. The ProTech 203 is recognized for its high safety integrity, often utilized in applications requiring SIL-3 (Safety Integrity Level) compliance, ensuring that the machine is shut down automatically if speed parameters exceed safe operational limits.

Technical Specifications

Parameter	Detail
Product Model	ProTech 203
Part Number	9905-998
Manufacturer	Woodward
Architecture	Triple Modular Redundant (TMR)
Input Channels	3 independent speed inputs (MPU or Proximity)
Safety Rating	SIL-3 Compliant
Communication	Modbus (RS-485)
Operating Voltage	18–32 VDC (Redundant Power)
Dimensions (Approx.)	250mm x 200mm x 150mm
Weight	~3.0 kg
Country of Origin	USA

Application Fields

Power Generation: Primary overspeed protection for critical utility-scale turbines.
Oil & Gas: Reliable shutdown protection for compressor drive turbines.
Marine Propulsion: High-speed protection for main propulsion turbines on large vessels.
Safety-Critical Systems: Any environment where mechanical overspeed poses a risk of equipment destruction or personnel injury.

Usage Instructions

Installation: The ProTech 203 should be panel-mounted in a clean, vibration-free environment. Ensure proper electrical bonding to the panel ground.
Wiring: Connect the three independent speed sensors (MPU or Proximity) to the dedicated input channels. Use shielded cabling to prevent noise induction, which could cause nuisance trips.
Redundancy: Wire the redundant 24V DC power inputs to independent power supplies to ensure the unit remains active even during a localized power failure.
Configuration: Use the Woodward service tool/software to configure setpoints, relay voting logic, and communication parameters.
Testing: The system supports “online testing,” allowing one of the three modules to be tested without tripping the turbine. Perform these tests periodically to satisfy safety requirements.

Frequently Asked Questions (Q&A)

Q: Why is TMR (Triple Modular Redundant) architecture important?
- A: TMR allows the system to continue operating safely even if one module fails. It provides “fail-safe” and “fault-tolerant” operation, significantly reducing the probability of both nuisance trips and failure-to-trip.
Q: Is the ProTech 203 compatible with my existing turbine control?
- A: Yes, it is designed to operate as an independent safety layer (independent of the main turbine controller/governor). It typically sends a trip signal to the emergency trip solenoid or block valve.
Q: Can I replace a module while the turbine is running?
- A: Yes, due to the TMR design, individual modules can be swapped during operation provided the remaining two modules are healthy and the “test” mode is correctly utilized.