Woodward 9907-147 ProTech 203 Overspeed Protection System

Configured for high-integrity turbomachinery monitoring, the Woodward 9907-147 (9907-147 Overspeed Protection System) provides direct physical/electrical execution of speed-sensing and trip logic sequences within prime mover protection platforms.

Hardware Specifications

Triple Modular Redundancy (TMR) 2oo3 Architecture

The 9907-147 utilizes a TMR 2oo3 architecture to ensure failsafe state execution during overspeed events. The system integrates three independent speed-sensing units that perform simultaneous frequency calculations based on magnetic pickup inputs. The internal voting logic requires at least two of the three units to detect an overspeed condition exceeding the programmed trip set point before the system transitions the output relays to the de-energized state. This redundancy prevents spurious trips caused by individual module drift or signal noise while maintaining high diagnostic coverage. Programming and operational state changes are governed by a physical key-locked interface, restricting access between MONITOR and PROGRAM modes to authorized personnel.

Frequently Asked Questions

Q: Is the system sensitive to electromagnetic interference (EMI)?

A: Yes, the 9907-147 is susceptible to EMI. It must be installed away from high-current or high-voltage devices. All signal cabling must utilize high-quality shielding, and shields should be grounded at the control cabinet entry point to maintain signal integrity for the magnetic pickup inputs.

Q: Can the trip set points for the three speed-sensing units be programmed independently?

A: While the interface allows for individual unit configuration, all three units must be programmed to identical trip set points to ensure the 2oo3 voting logic functions accurately. Mismatched set points will result in indeterminate relay behavior during speed transitions.

Field Installation Guidelines

1. Mounting: Install the unit in a climate-controlled enclosure with adequate clearance for ventilation. Ensure the location is protected from direct sunlight, moisture, and excessive vibration, maintaining the ambient temperature within the -25 to 60 deg C range.
2. Wiring: Use shielded twisted-pair conductors for all magnetic pickup connections. Ensure the cable length and impedance conform to the specific MPU characteristics to stay within the 100 Hz to 32 kHz sensing frequency range.
3. Grounding: Connect the chassis to a dedicated earth ground bus to minimize noise susceptibility. Ensure that all redundant power supply inputs (if applicable) share a common reference point to prevent ground loops across the TMR modules.
4. Validation: During commissioning, verify the 2oo3 voting logic by simulating trip signals on individual modules. Confirm that the relay outputs only transition to a trip state when a minimum of two units indicate an overspeed condition.