9907-147

About the 9907-147

Model 9907-147 uses magnetic pickups to monitor primer speed for overspeed conditions. Devices in this series are susceptible to electromagnetic interference, vibration, moisture, and temperatures outside of the operating temp range of –25 to +60 °C (–13 to +140 °F). ProTech overspeed protection models should be installed in locations that allow adequate ventilation for cooling, space for servicing, and away from direct sunlight, and away from high-current or high-voltage devices.

This de-energize-to-trip system has a 100 Hz to 32 kHz speed-sensing frequency range and a ±(0.05% x Trip Point in Hz +2 Hz) accuracy rating. Overspeed detection functions are carried out by three individual speed-sensing units, which act independently to monitor speed and perform speed calculations. The three units are in a two-out-of-three vote configuration, so a prime mover trip relay will only occur if overspeed conditions are detected by at least two of the units.

The trip-point frequency range of ProTech overspeed protection model 9907-147 is 250 Hz to 25 kHz. Trip set points are programmed for each of the units separately (they must be programmed identically for accurate outputs) using the operator interfaces. There is one interface per speed-sensing unit. Each one has:

• Two-line by 16-character LCD display
• Touchpad
• Potentiometer
• LED indicators
• Alarm output

Programming and testing functions are locked to prevent unauthorized changes. One key switch to move between MONITOR mode and PROGRAM mode is connected to all three units.