1. General Information

• Manufacturer: Bently Nevada (Baker Hughes)

• Model Number: 3500/32

• Main Board Part Number: 125712-01

• Rear I/O Board: 125720-01 (Standard Relay Terminal Board)

• Product Name: Four-Channel Relay Output Module (Legacy Version)

• Series: 3500 Machinery Protection System

• Module Type: Full-height basic relay module (Old Generation)

• Application: Provides four independent dry contact alarm outputs for vibration, temperature and position monitor modules; used for conventional alarm interlock, DCS signal transmission; widely applied in old power plant rack system, replaced by enhanced 3500/32M.

• Installation Rule: Any full-height slot in 3500 rack

• Compliance: API 670

2. Functional Description

• Channel Quantity: 4 independent relay output channels

• Contact Type: SPDT dry contact (NO / NC / COM)

• Logic Mode: Normally Energized / Normally De-energized

• Logic Function: Basic alarm logic, simple gating only

• Action Response: Mechanical relay contact action

3. Electrical Specifications

• Backplane Power: +5 VDC from rack backplane

• Power Consumption: 6.0 W typical

• Resistive Load Rating: 250 VAC / 5 A ; 30 VDC / 5 A

• Inductive Load Rating: 250 VAC / 2.5 A ; 30 VDC / 2.5 A

• Response Time: ≤ 5 ms relay switching time

• 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: Full-height single slot legacy relay module

• Dimensions (H × W × D): 241.3 × 24.4 × 99.1 mm

• Weight: Approximately 0.51 kg

• Mounting: Hot-swap capable, general installation slot

6. Compatible Devices

• Matching Rear Board: 125720-01 (Old version relay terminal board)

• Compatible Modules: All conventional 3500 monitor modules

• Rack Chassis: Early standard 3500 rack

7. Key Features

• Four isolated mechanical relays for basic alarm dry contact output

• Simple stable circuit, low failure rate for old industrial system

• Standard contact rating for common interlock loop

• Epoxy sealed circuit board for dust & moisture resistance

• Cost-effective for non-complex conventional alarm logic

8. Critical Relay Module Comparison (Most Important)

• 3500/32 (125712-01): Old basic version, simple logic, no advanced latch/gating function.

• 3500/32M (141533-01): New enhanced version, rich logic, latch/AND/OR programmable.

• 3500/34: SIL3 TMR trip version, 2oo3 voting for ETS turbine trip.