Description
Woodward’s ProTech series model 9905-873 consists of three units connected in a two-out-of-3 voting configuration so that if any single unit fails, the ProTech system will still provide the correct output. It is engineered specifically to provide ultra-reliable, fail-safe overspeed protection and critical monitoring for industrial turbomachinery, including steam, gas, and hydro turbines. The triple-modular redundant (TMR) architecture ensures high availability while eliminating single points of failure that could cause nuisance shutdowns or catastrophic overspeed events.
📊 Technical Specifications & Datasheet Parameters
• Brand: Woodward
• Model: 9905-873
• Series: ProTech
• Product Name: Overspeed Protection System
• Place of Origin: United States
• Operational Status: Active / Industrial Grade
• Dimensions: Approximately 300 mm × 250 mm × 150 mm (11.8 in × 9.8 in × 5.9 in)
• Weight: Approximately 4.4 kg (9.7 lbs)
• Country of Origin: United States
• Power Consumption / Power: 24 V DC redundant power supply inputs (Max 50 W)
⚙️ Operation Standards & Usage Methods
Installation must strictly adhere to the manufacturer’s technical manual and be executed by qualified, certified control system engineers. The device should be mounted securely in a standard industrial control panel or rack enclosure rated for the appropriate NEMA/IP environment to shield internal electronics from excessive dust, moisture, and vibration. All field wiring, speed sensor connections (magnetic pickups or proximitors), and relay outputs must be shielded and properly grounded to eliminate electromagnetic interference (EMI). Configuration of trip limits, sensor types, and voting logic must be validated using the secure front-panel interface or configuration software before commissioning the turbine train.
🔌 Power-Up & Power-Down Sequence
Power-Up Sequence:
- Verify that all field wiring, speed sensors, and actuator trip circuits are correctly terminated and secure.
- Energize the primary and secondary redundant 24 V DC power supply feeds to the unit.
- Observe the internal diagnostic LEDs and front display to confirm that all three units pass their self-test routines without faults.
- Verify that the system configuration parameters match the mechanical specifications of the turbine.
- Arm the trip output relays only when the machinery is ready for operation.
Power-Down Sequence:
- Ensure the turbine or controlled machinery has been safely brought to a complete standstill and is in a de-energized state.
- Disengage and lock out the trip output circuits to prevent accidental signals.
- Power down the redundant 24 V DC supply inputs to the 9905-873 unit.
- Wait for internal capacitors to fully discharge before performing any maintenance, module replacement, or inspection work.
❓ Frequently Asked Questions (Q&A)
Q: How does the two-out-of-three voting configuration maintain protection during a failure?
A: By connecting three units in a 2oo3 configuration, the system requires agreement from at least two units to initiate a trip. If any single unit fails, the remaining two units can still provide the correct output, ensuring continuous safety and preventing nuisance shutdowns.
Q: Can the units be serviced while the turbine is running?
A: Yes, the ProTech system architecture allows for high reliability and maintainability under specific operational guidelines, letting operators monitor system health without taking the entire safety system offline.
Q: What types of speed sensors are compatible with this device?
A: The unit accepts inputs from standard passive magnetic pickups (MPUs) and active proximity probes commonly used on industrial rotating machinery.
🚀 Recommended Woodward Models
- Woodward 9905-753 (ProTech Electronic 2oo3 Protection System)
- Woodward 8237-1596 (ProTech-GII Overspeed Protection Device)
- Woodward 8200-203 (ProTech 203 Standard Configuration)
- Woodward 8200-207 (ProTech 203 24 VDC Model)
- Woodward 8200-211 (ProTech 203 De-energize-to-Trip Model)
- Woodward 5464-672 (MicroNet Plus Control System)
- Woodward 8200-220 (505 Digital Turbine Controller)
- Woodward 8200-221 (505E Export and Extraction Turbine Controller)
- Woodward 9907-162 (2301D Digital Load Sharing and Speed Control)
- Woodward 8404-204 (723PLUS Digital Governor)
