WOODWARD 9907-149 Electronic over-speed tripping device

9907-149 ProTech 203 Electronic Overspeed Trip Device from Woodward that senses prime mover speed through three magnetic pickups (MPUs).

9907-149 Technical Specifications
Dimensions W19in x H12.244in x D5.62in
Features Hot Replacement
Input Voltage 120 Vac/dc
Keypad/Display 1 display and keypad per module
Manual 85204
Model De-energize-to-Trip
Operating Temperature –13 to +140 °F
Standards NEMA 4/4x, IP54

ProTech model 9907-149 is a 120 Vac/dc device. There is a separate power supply for each of the three speed-sensing units in this system. This is part of the modular design of this Woodward overspeed protection device that enables such features as hot replacement of an individual unit and testing of individual units without taking the prime mover offline.

Speed-sensing units A, B, and C in model 9907-149 are identical. On top of having separate power supplies, the units also have separate operator interfaces and alarm systems. The three units are configured for a two-out-of-three voting method. Prior to this hardware vote, the three units act independently, monitoring prime mover speed with magnetic pickups (MPUs) and individually performing speed calculations.

The three units that makeup ProTech model 9907-149 must be programmed with identical trip points. PROGRAM mode is accessed with a key switch that is connected to all three units. Due to the modular design of this Woodward system, units are programmed separately.

Tunable parameters are set when the units are in PROGRAM mode. These parameters are:

• Trip Speed Set Point (250 rpm to 25,000 rpm)
• MPU Gear Teeth (20 to 120)
• MPU Failed Timeout (1 sec to 533 min 20 sec)
• MPU Failed Set Point (100 rpm to 25,000 rpm)
• Trip on MPU Failure
• Timer Starts on Reset
• Alarm If Speed Is < MPU Failed Set Point