The Woodward 9907-147 is a high-integrity overspeed protection system part of the ProTech 203 series. It monitors prime mover speed through three independent magnetic pickups (MPUs) and utilizes a two-out-of-three (2oo3) voting architecture to ensure reliable engine and turbine protection.
Specifications
Part Number:9907-147.
Input Voltage:18 to 32 Vdc (24 Vdc nominal).
Speed Sensing Range:100 Hz to 32 kHz.
Trip Point Range:250 Hz to 25 kHz.
Total Response Time:40 ms maximum.
Accuracy:±(0.05% x Trip Point in Hz + 2 Hz).
Operating Temperature:-25°C to +60°C.
Dimensions:482.6 mm x 310.4 mm x 142.7 mm.
Weight:Less than 17 lbs (approx. 7.3 kg).
System Type:De-energize-to-trip.
Features
Two-out-of-Three Voting:Employs three independent speed-sensing units that must agree for a trip to activate, significantly reducing false trips.
Hot Replacement:Each of the three units can be replaced while the device is running without tripping the prime mover.
Built-in Self-Test:Features an integral frequency generator that allows online testing of each unit individually.
High-Speed Sampling:Monitors and samples speed every 5 milliseconds to ensure rapid detection of anomalies.
Secure Access:Includes a lockable enclosure and a single key switch to toggle between Monitor and Program modes, preventing unauthorized changes.
Individual LCD Displays:Each sensing unit is equipped with a two-line, 16-character LCD to show current speed, peak speed, and trip status.
Diagnostic Indicators:Dedicated LEDs provide immediate visual feedback on CPU health, MPU failure, and trip status.
Independent Power Sources:Each unit is operated from a separate power source to further enhance system reliability.
