9907-148

About the 9907-148

Prime mover speed monitoring is carried by three magnetic pickups, each one interfaced with a separate speed-sensing unit. Units act independently for speed sampling and speed calculation functions and are connected in a two-out-of-three-vote configuration for prime mover overspeed condition detection.

The configuration of this Woodward ProTech system permits speed-sensing units to be tested individually without taking the prime mover offline. This also means that any individual unit in the 9907-148 model can be replaced while the device is running. All three units have their own 120 Vac/dc power supply and their own operator interface.

Model 9907-148 is an energize-to-trip model. In the event there is a loss of power, the prime mover may not trip. Energize-to-trip overspeed protection models should only be used in applications that require an energize-to-trip system. Woodward ProTech Manual 85204 (G) has a table showing available ProTech models in both energize-to-trip and de-energize-to-trip options. These models can be configured for compatibility with a variety of power source combinations, most of which are available through AX Control.

Like other models in the ProTech Overspeed Protection System series, 9907-148 has a remote reset feature. Before the turbine is started, or after a trip, units must be reset. The remote reset feature allows operators to reset the units from a remote location.

ProTech model 9907-178 also has a NEMA 4 and 4X certified enclosure, which is locked to prevent access to programming and testing functions by unauthorized personnel.