9907-345 | Woodward ProTech 203 Overspeed Protection

The 9907-345 ProTech 203 Overspeed Protection System is a digital trip device designed to monitor prime mover speed using three magnetic pickups (MPUs). It consists of three identical, independent speed-sensing units that continuously check the speed and activate a trip relay if an overspeed condition occurs. These units are connected in a two-out-of-three voting configuration, ensuring that the system will still operate correctly even if one unit fails.

Key Features

• Speed Monitoring: Continuous monitoring of prime mover speed with three independent sensors.
• Trip Relay Configuration: Uses a two-out-of-three voting system for reliability.
• Speed Display: Shows actual speed from each probe and the highest speed signal.
• On-line Testing: Allows for modular design, enabling single unit replacement while running.
• LED Indicators: Functional status indicated by light-emitting diodes (LEDs) and digital displays on the front panel.

Applications

The ProTech system is available in two models:

• De-energize-to-trip model
• Energize-to-trip model

Warning: Woodward strongly recommends using the de-energize-to-trip model for safety reasons. An energize-to-trip model may not trip on loss of power, potentially leading to property damage or personal injury.

Specifications

Specification	Details
Enclosure	Approved for Type 4 and 4x environments (NA); IP54 rated (EU)
Remote Reset	Can be reset remotely
Contact Input	Configurable as remote start or speed sensing
Built-In Self-Test	Frequency generator for on-line testing
Key Lock	Prevents unauthorized programming/testing
Replacement	Subsystems replaceable while others powered
Outputs	Separate alarm output and LED for trip status
MPU Failure Indications	LEDs for MPU or wiring failure
MPU Fail Timer	Programmable timer to trip if speed is low
MPU Fail Option	Configurable alarm and trip signal settings
CPU Failure Indication	LED for CPU operation status
Speed-Sensing Frequency Range	100 Hz to 32 kHz
Trip-Point Frequency Range	250 Hz to 25 kHz
MPU Input Amplitude	1 Vrms min at 100 Hz to 25 kHz; 2 Vrms min at 25 kHz to 32 kHz; max 25 Vrms
Shutdown Contact Ratings	Various UL and European ratings
Alarm Contact Ratings	Various UL and European ratings
MPU Measurement Circuit Input Impedance	2 kΩ
Accuracy	±(0.05% x Trip Point in Hz +2 Hz)
Operating Temperature	–25 to +60 °C (–13 to +140 °F)
Display Operating Temperature	–15 to +60 °C (+5 to +140 °F)
Sample Time	Speed sampled every 5 ms
Total Response Time	40 ms max
Humidity	Complies with US MIL-STD-810D, Method 507.2, Procedure II
Vibration	Complies with US MIL-STD-810D, Method 516.3, Procedure I

Voltage Ranges

The ProTech system can be configured for various power sources:

Table 1-1: De-energize-to-Trip ProTech Models

Part Number	Unit A	Unit B	Unit C
9907-345	24 Vdc	24 Vdc	24 Vdc

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