9907-145

About the 9907-145

Woodward overspeed protection device model 9907-145 uses magnetic pickups (MPUs) to monitor prime mover speed. This ProTech energize-to-trip system has several features that make programming and monitoring MPU functions easy.

MPUs in the 9907-145 system are interfaced with three separate speed-sensing units, each with its own operator interface. On each interface is a separate LED to indicate the status of that unit’s MPU. If an MPU or its wiring fails, the corresponding LED will illuminate. With the 9907-145 model operators have the option to configure each unit to either output both an alarm and a trip signal, or to output only an alarm if that unit’s MPU is lost.

MPU Fail Timeout, MPU Failed Setpoint, and Trip on MPU Failure are a few of the 9907-145 tunable parameters. A complete list of tunable parameters and their functions is in Woodward ProTech manual 85191. These parameters are both programmed and monitored with the keypad and LCD on each operator interface. Speed-sensing units are programmed individually but must be programmed with identical trip points.

Units are programmed separately due to the modular design of model 9907-145, a design that permits features such as a two-out-of-three voting configuration and hot replacement of any individual speed-sensing unit. For these reasons, there is a separate 120 Vac/dc power supply (voltage range of 88–132 Vac/90–150 Vdc, 7.25 W) for each unit.