9907-147 ProTech 203 De-Energize-to-Trip Overspeed

9907-147 

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.