9907-345

About the 9907-345

Hot replacement, built-in self-test, remote reset, and multiple alarm outputs are just a few of the features available with this ProTech model. This overspeed protection device has three magnetic pickups (MPUs) which are in three separate speed-sensing units. Each unit, A, B, and C, actuates two-voter relays.

Units A, B, and C function independently prior to the hardware vote, and each one has a separate operator interface and 24 Vdc power supply. It is this design and voter relay configuration that permit some of model 9907-345’s features, such as the ability to test or replace individual units without taking the prime mover offline.

Because of this modular design, each unit also has its own alarms, both visual and audible. Error messages on a unit’s LCD display and LEDs indicate various issues such as MPU fail timeout or a failed CPU. On top of these visual indicators, problems that may require attention will also trigger an alarm output.

ProTech model 9907-345 has a 250 Hz to 25 kHz frequency range. The allowable range for MPU Failed Timeout is 100 rpm to 25,000 rpm. This de-energize-to-trip system is in a NEMA 4 and 4X certified enclosure.

ProTech overspeed protection devices are susceptible to electromagnetic interference. Precautions must be taken to protect this device from high-currency and high-voltage devices, as well as from vibration. Location considerations for ProTech model 9907-345 can be found in the device manual, ProTech 203 Overspeed Protection System Manual 85205 (Revision F). Additional Woodward manuals that contain information relevant to this system are manuals 82715, 82510, and 50532.