9905-869 is part of the ProTech 203 Overspeed Protection System. This model is one of the de-energize-to-trip versions in the Woodward series. When an overspeed condition is detected, a trip relay is activated. The accuracy of this system is ensured through the use of a two-out-of-three voting configuration of the three speed-sensing units. The actual speed of any of the three units can be viewed on the LCD of each unit’s own operator interface. Each interface also has a keypad and LED functional status indicators.
Thanks to the hardware vote configuration, the 9905-869 will continue to operate even after one of the unit trips. Along with an overspeed condition detection, there are several possible reasons why one of the units may trip, including but not limited to the loss of an MPU signal, the unit was not reset before the turbine was restarted, or an interlock fault. More information on the trip relays and troubleshooting information can be found online in the ProTech 203 Overspeed Protection System Manual 85191 (version B)
1 Year Warranty
