9907-085

About the 9907-085

ProTech 203 overspeed protection model 9907-085 has an accuracy rating of 0.05% of point + 2 Hz over the operating temperature range (–25 to +60 °C). This device detects overspeed conditions by using three individual speed-sensing units to monitor prime mover speed using magnetic pickups (MPUs).

The three units then perform their own speed calculations, and a two-out-of-three hardware vote determines whether a trip relay is activated. It takes two units to detect overspeed conditions to trip the system. Detection from only one will trip that unit, but the other two will take over control of the process and the device will continue running. The total system response time, from speed sampling to trip relay activation, is 40 ms max.

Trip set points for the three units are programmed for each speed-sensing unit individually but must be programmed identically. Woodward Manual 85203 details the 9907-085 tunable parameters and contains a programming worksheet.

This ProTech system permits fast error identification and troubleshooting with its various error and failure indicators. Each speed-sensing unit operator interface has an LCD where error codes are displayed if something needs attention. Situations such as an MPU failure, CPU failure, or a tripped unit are announced through separate LEDs. For some events requiring attention, a tripped unit, for example, will also trigger an alarm output.

This 220 Vac overspeed protection device is sensitive to electromagnetic interference and vibration. ProTech 203 manual 85203 should be consulted for a full list of location considerations and safety precautions.