9905-981

About the 9905-981

Part 9905-981 is in the ProTech 203 Overspeed Protection System series, manufactured by Woodward. This model is one of the energize-to-trip versions, so a cold-coil monitoring device must be wired in if this system is to meet the API 612 overspeed trip specifications.

Three magnetic pickups (MPUs), one per speed-sensing unit, continually monitor prime mover speed. Each of the units, A, B, and C, actuate two voter relays. The three units are configured so that a two-out-of-three hardware vote determines whether a trip relay is activated. An individual unit will trip if it detects an overspeed condition, but as long as two of the three units are online the system will continue running.

The 9905-981 overspeed protection system is designed for use in locations where an operating temperature range of –25 to +60 °C (–13 to +140 °F) can be maintained, a –15 to +60 °C (+5 to +140 °F) range for the display. This device needs adequate room for ventilation, and it should be protected from vibration, electromagnetic interference, direct sunlight, and moisture.

ProTech 203 manual 85195 has additional location considerations and product specifications. This manual contains in-depth information on 9905-981 features such as hot replacement, built-in self-test, and online testing.

To ensure proper installation and operation requirements and procedures are followed, manuals 82715, 82510, and 50532 should also be reviewed.