9907-083

About the 9907-083

Woodward ProTech model 9907-083 uses magnetic pickups (MPUs) to sample prime mover speed. This is done every 5 ms. In 40 ms or less, the system samples speed, performs three separate speed calculations, puts these calculations to a two-out-of-three hardware vote, and if overspeed conditions are detected, activates a trip relay.

Model 9907-083 is an energize-to-trip model and may not trigger a trip relay if a loss of power occurs. Please refer to Woodward ProTech Manual 85203 for relevant safety information for this overspeed protection system.

The three-speed calculations are carried out by three separate speed-sensing units. Units A, B, and C are identical. Each one has its own 24 Vdc power supply and operator interface.

Model 9907-083 has a key switch connected to all three speed-sensing units. This key switch controls access to PROGRAM mode. The ProTech 203 overspeed protection system will run in either PROGRAM mode or MONITOR mode but should only be put in PROGRAM mode when necessary to prevent unauthorized changes or testing.

There are five tunable parameters on ProTech model 9907-083. These are:

• Trip Speed Set Point
• Trip on MPU Failure
• MPU Failed Set Point
• MPU Failed Timeout
• MPU Gear Teeth

The modular design of the 9907-083 overspeed protection system requires that each speed-sensing be programmed separately. They must be programmed with identical trip points for the system to work correctly and safely.