9905-754

About the 9905-754

Woodward offers many overspeed protection device versions in the company’s ProTech 203 series. Model 9905-754 is one of the series energize-to-trip models. The three speed-sensing units in this model are identical. They all have a 24Vdc input voltage, with a voltage range of 18–32 Vdc, 7.25 W. Since this is an energize-to-trip model, the interposing relay will not actuate if power to the 9905-754 system is lost. Details on this and other product considerations may be found in Woodward Manual 85196.

Each of the three speed-sensing units is interfaced with a separate magnetic pickup (MPU) to monitor prime mover speed. If overspeed is detected, a trip relay is activated. This is accomplished by a two-out-of-three hardware vote.

The design of the 9905-754 overspeed protection system permits online testing since the system can operate normally with only two units if needed. Along with online testing and reduced downtime, this also allows for a single failed unit to be replaced without disrupting operations.

The three units each have a front panel with a touchpad, LCD and functional status LED indicators. The actual speed of each unit can be viewed on this front panel. It is through these operator interfaces that the units are programmed, which can only be accessed with a key.