9905-903

About the 9905-903

This dual relay overspeed protection device has three displays on the front panel, one for each of the three speed-sensing units in the enclosure. Each unit also has its own keypad and functional status LEDs. The internal units are configured for two-out-three hardware voting. The three units within the ProTech 9905-903 dual relay overspeed protection device are programmed individually but must be programmed with identical trip points for proper functioning.

9905-903 units are programmed using the display and keypad on the front panel. PROGRAM mode access is limited to those with key access to the NEMA 4 enclosure. A few of the tunable parameters available with the 9905-903 device are trip speed setpoint, MPU failed setpoint, and MPU failed timeout. A complete list of tunable parameters as well as programming instructions can be found in Woodward ProTech 203 Overspeed Protection System Manual 85201.

There are nine parameters operators can view one at a time on each of the three LCD displays on the 9905-903’s front panel. The current speed for the corresponding speed-sensing unit is the default first parameter shown. These front panel LCDs are also used to display error messages, including MPU FAILED, NO RESET, MPU>TRIP SETPT, and more.

Woodward Manual 85201 has more specifications for the 9905-203 overspeed device as well as location requirements, environmental requirements, etc., but there are a few more manuals Woodward recommends consulting before installing this system. Manuals 82715, 82510, 50532, and 85562 all contain information relevant to the proper handling and operation of this ProTech 203 dual relay model.