1. General Information

• Manufacturer: Bently Nevada (Baker Hughes)

• Model Number: 3500/25

• Main Board Part Number: 149369-01

• Rear I/O Board: 125800-02 (Keyphasor Terminal Board)

• Product Name: Enhanced Keyphasor Module

• Series: 3500 Machinery Protection System

• Module Type: Half-height dual-channel keyphasor & speed module

• Application: Shaft phase reference & rotational speed monitoring for turbine, compressor and high-speed rotating machinery; provides synchronous phase signal for vibration spectrum, orbit and transient analysis; mandatory card for rotor dynamic diagnosis.

• Installation Rule: Any half-height slot inside 3500 rack

• Compliance: API 670

2. Functional Description

• Channel Configuration: 2 independent keyphasor input channels

• Supported Sensor: Eddy-current probe / Magnetic pickup sensor

• Monitoring Parameter: Rotational Speed, Shaft Phase Angle, Keyphasor Pulse

• Signal Output: Digital TTL keyphase pulse for system synchronization

• Analysis Function: Supports Bode plot, Polar plot, Shaft orbit analysis

3. Electrical Specifications

• Backplane Power: +5 VDC from rack backplane

• Power Consumption: 3.2 W typical (Ultra-low power)

• Sensor Power: -24 VDC for proximity keyphasor probe

• Frequency Range: 0.017 Hz ~ 15 kHz

• Input Impedance: 21.8 kΩ minimum high impedance input

• Speed Accuracy: ±1 CPM (High precision speed tracking)

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

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 single slot compact module

• Dimensions (H × W × D): 241.3 × 12.2 × 99.1 mm

• Weight: Approximately 0.32 kg

• Mounting: Hot-swap capable, half-height slot installation

6. Compatible Devices

• Matching Rear Board: 125800-02 (Exclusive keyphasor terminal board)

• Applicable Sensor: Standard keyphasor probe, magnetic speed sensor

• Cooperated Module: 40M/42M vibration monitor, 22M TDI waveform acquisition

• Rack Chassis: All standard 3500 series racks

7. Key Features

• Dual-channel redundant keyphase signal acquisition for rotating shaft

• High precision speed measurement for variable-speed turbine units

• Provides phase reference for vibration spectrum & orbit analysis

• Half-height design saves rack slot space

• Ultra-low power consumption for long-term stable operation

8. Core Definition (Most Important)

• What is Keyphasor: One pulse per shaft revolution, phase benchmark.

• 3500/25 Function: Speed + Phase, no vibration value, only reference signal.

• Matching Logic: Must cooperate with vibration cards for spectrum analysis.

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