9907-082

About the 9907-082

Magnetic pickups (MPUs) continuously monitor prime mover speed in this overspeed protection device by Woodward. Speed is sampled every 5 ms, three separate speed calculations are performed, and a subsequent two-out-of-three vote takes place. A trip relay is activated if the results of this hardware vote detect overspeed conditions. Overall, this process has a total response time of 40 ms max.

Model 9907-082 is a 220 Vac system. Each of the three speed-sensing units in this model has its own 220 Vac power supply (180-264 Vac, 7.25 watts voltage range). Because this is an energize-to-trip model, loss of power will not automatically result in a prime mover trip. Woodward ProTech Manual 85203 contains additional safety information for this model.

The same modular design that permits the two-out-of-three voter relay configuration enables several other features as well. Overspeed protection model 9907-082 has a built-in frequency generator, which allows operators to test individual units without taking the prime mover offline. Similarly, a unit can be replaced while the device is running.

Other noteworthy features of ProTech 203 model 9907-082 are:

• Remote reset
• NEMA 4X certified enclosure (when optional stainless steel hubs are used)
• Key lock to access programming of the device
• LED indicators for the event of an MPU or CPU failure
• LED and alarm output to indicate a tripped speed-sensing unit