9905-885

About the 9905-885

ProTech 203 models 9905-885 is an overspeed protection system in a NEMA 4X standard enclosure (if optional stainless steel hubs are used). This device uses magnetic pickups (MPUs) to detect overspeed conditions and activate a trip relay if conditions are met. The 9905-885 model is an energize-to-trip model of three identical speed-sensing units.

This model boasts a speed sample time of 5ms, with a total response time of only 40 ms. It has a speed-sensing frequency range of 100 Hz to 32 kHz. The ProTech 203 model 9905-885 has an accuracy rating of 0.1% (at 25 °C).

When a trip relay occurs, it is indicated by both an alarm output and an LED on the front of the tripped speed-sensing unit. The two-out-of-three vote configuration of the units means that if only one unit trips, the system can continue operating. If two units trip, the system will stop operations. The 9905-885 system has a trip-point frequency range of 250 Hz to 25 kHz.

There are three operator interfaces on the front of the 9905-885 system, one for each unit inside. These interfaces have a two-line LCD, a keypad, and their own set of LED functional status indicators. The LCD can display the present speed, the peak speed, the trip speed set-point, and the trip cause, among other parameters.

Additional features of model 9905-885 that make it a good choice for overspeed protection applications include:

• Hot replacement
• Built-in self-test
• Remote reset
• MPU failure indicator
• CPU failure indicator

A complete list of parameters that can be displayed as well as additional features of model 9905-885 may be found in ProTech 203 Manual 85191 (version B).