1. General Information

• Manufacturer: Bently Nevada (Baker Hughes)

• Part Number: 133396-01

• Product Name: Overspeed Detection Rear I/O Termination Board

• Applicable Module: 3500/53 Electronic Overspeed Detection Module

• Module Type: Full-height rear I/O daughter board

• Application: Provides field termination for three keyphasor speed sensors, analog output and system wiring; responsible for signal filtering, conditioning and isolation for turbine overspeed safety loop.

• Installation Rule: Installed on the rear side of 3500/53 main board

• Compliance: API 670, API 612

2. Interface Definition

• Keyphasor Input Terminal: 3-channel independent speed sensor termination

• Transducer Power: -24 VDC sensor power supply for eddy-current probe

• Analog Output Terminal: 1-channel 4-20mA isolated speed output for DCS

• Internal Connector: Gold finger interface for connecting 3500/53 main board

• Shielding Terminal: Common shielding grounding point for anti-interference

3. Electrical Specifications

• Sensor Power Output: -24 VDC, Max 40 mA per channel

• Input Frequency Range: 0.017 Hz ~ 20 kHz

• Analog Output Load: Max 600 Ω for 4-20mA loop

• Isolation Voltage: 1500 VAC channel-to-system isolation

• Terminal Rating: 300 V industrial screw terminal block

• Circuit Protection: Built-in surge and short-circuit protection

• 4. Environmental Specifications

  • Operating Temperature: -30 °C ~ +65 °C (-22 °F ~ +149 °F)

  • Storage Temperature: -40 °C ~ +85 °C (-40 °F ~ +185 °F)

  • Relative Humidity: 5% ~ 95% (Non-condensing)

  • Anti-vibration: Compliant with API 670 industrial vibration standard

  5. Mechanical Specifications

  • Structure: Full-height rear termination daughter board

  • Dimensions (H × W × D): 242 × 22 × 160 mm

  • Weight: Approximately 0.24 kg

  • Mounting: Fixed on back of 3500/53, non-detachable during normal operation

  6. Compatible Devices

  Exclusively compatible with 3500/53 overspeed detection main board; matched with 3500/34 TMR relay module to constitute SIL3 turbine ETS overspeed trip system.

  7. Key Features

  • Three-channel isolated keyphasor signal acquisition for redundant speed measurement

  • High noise immunity circuit for harsh power plant electromagnetic environment

  • Isolated 4-20mA speed analog output for remote DCS monitoring

  • Epoxy sealed circuit board for dust and moisture resistance

  • Safety-level signal termination for turbine overspeed protection loop

  8. Difference Between Main Board & I/O Board

  • 3500/53: Main control board, logic calculation & trip judgment.

  • 133396-01: Rear I/O board, wiring terminal & signal conditioning.