1. General Information

• Manufacturer: Bently Nevada (Baker Hughes)

• Part Number: 125800-01

• Product Name: Isolated Keyphasor I/O Module

• Applicable Module: 3500/25 Enhanced Keyphasor Module

• Module Type: Half‑height rear I/O termination daughter board

• Application: Provide isolated keyphasor signal termination, signal conditioning and buffered output; Collect shaft speed and phase pulse signal from proximity probe or magnetic pickup.

• Installation Rule: Installed on the rear side of 3500/25 module

• Compliance: API 670

2. Interface Definition

• Keyphasor Input Terminal: 2 channels isolated transducer input terminals

• Buffered Output: 2 channels buffered keyphasor pulse output for external system

• Internal Connector: Gold finger interface for connecting 3500/25 main board

• Signal Isolation: Channel-to-channel electrical isolation design

3. Electrical Specifications

• Sensor Power: -24 VDC for proximity transducer

• Input Impedance: 21.8 kΩ minimum per channel

• Frequency Range: 0.017 Hz ~ 20 kHz

• Isolation Voltage: 1500 VAC isolation strength

• Phase Accuracy: ±0.1° phase measurement error

• Output Impedance: ≤ 504 Ω buffered output impedance

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: Half-height rear termination daughter board

• Dimensions (H × W × D): 242 × 112 × 25 mm

• Weight: Approximately 0.38 kg

• Mounting: Fixed on back of 3500/25, non-detachable during normal operation

6. Compatible Devices

7. Key Features

• Dual-channel isolated keyphasor signal acquisition

• High precision phase & speed monitoring for rotating machinery

• Independent buffered pulse output for third-party system backup monitoring

• Excellent anti-interference performance for harsh industrial field

• Standard matching rear I/O board for 3500/25 assembly

8. Difference between 125800-01 & 125388-01H

• 125800-01: Keyphasor I/O board, dedicated for 3500/25, speed & phase signal terminal.

• 125388-01H: Empty half-height metal chassis, universal housing for all half-height modules.