9905-881

About the 9905-881

ProTech 203 model 9905-881 has many features that make it a smart choice for your overspeed protection needs. This de-energize-to-trip system has a remote reset feature, which allows it to be conveniently reset from a remote location after a trip or before starting the turbine. The 9905-881 also has LED indicators for each of the system’s three-speed sensing units, allowing operators to quickly identify any system or hardware issues, or at least know where to start troubleshooting.

Model 9905-881 provides an accurate output by way of a two-out-of-three hardware vote configuration. The design of this system permits the prime mover to remain online even if only two of the three units are functioning. This means that should one of the unit trips, is being tested, or is being replaced, operations may continue with an accurate, reliable output.  

This ProTech 203 model has three magnetic pickups (MPUs). These MPUs are each interfaced with a speed-sensing unit. The individual 9905-881 units have their own operator interface, and all units are in a single, key-locked enclosure. NEMA 4X standards are met only if the optional stainless steel hubs are used.

Operator interface features include:

• LCD display
• Keypad
• Functional status LED indicators

Along with having individual operator interfaces, each speed-sensing unit also has its own power supply. On model 9905-881, Unit A and Unit B both have a 24 Vdc power supply, and Unit C has a 120 Vac/dc power supply. More information may be found in Woodward ProTech 203 Manual 85191 (version B).