9905-882

About the 9905-882

Reduce system downtime with the ProTech 203 Overspeed Protection System by Woodward. These systems continually monitor prime mover speed to activate a trip relay at the detection of overspeed conditions. This version, model 9905-882, is a de-energize-to-trip system. The modular design of this ProTech 203 system both ensures a high level of accuracy (0.1% at 25 °C) and permits normal operations during times other systems may require a full system stop.

Model 9905-882 uses magnetic pickups (MPUs) to monitor prime mover speed. Speed calculations are performed by three separate speed sensing units, connected in a two-out-of-three voting configuration. These three units that make up the 9905-882 are identical aside from their power supplies, which are as follows:

• Unit A: 24 Vdc
• Unit B: 24 Vdc
• Unit C: 220 Vac

ProTech 203 model 9905-882 will function even if one of the speed-sensing units is offline. This means that the units can be tested one at a time or one can be replaced without the prime mover being taken offline. If one of the units is tripped, the other two will continue providing an accurate output. Speed-sensing units will remain tripped until the power is cycled or they are reset, and each one of them must be reset before the turbine is started.

ProTech 203 Overspeed Protection System Manual 85191 has more specifications and information about model 9905-882, including factors that should be considered when choosing an installation location. The enclosure of ProTech 203 model 9905-882 must use the optional stainless steel hubs in order to be certified NEMA 4X.