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Product Description
The Bently Nevada 3500/34 Triple Modular Redundant (TMR) Relay Module (125696-01) is the relay module of choice for safety-critical machinery protection applications using the 3500 Machinery Protection System. Unlike standard relay modules, the 3500/34 uses a triple modular redundant voting architecture — combining the outputs of three independent channels into one voting relay output — dramatically reducing the risk of both false trips and failure-to-trip events.
The 3500/34 module itself mounts in the 3500 rack and works together with external relay modules (e.g., P/N 125696-01 style relay hardware) located at the rear of the rack, providing voting relay outputs that can be wired directly into turbine control and shutdown systems.
When monitor modules such as the 3500/42M, 3500/45, or 3500/53 detect a dangerous condition, the 3500/34 executes programmable alarm logic (AND/OR voting with selectable time delays) and de-energizes its relay outputs to initiate a protective shutdown — protecting steam turbines, gas turbines, compressors, and other high-value rotating equipment.
The 3500/34 is the standard solution in API 670-compliant protection systems where TMR reliability is required, including power plants, LNG facilities, refineries, and offshore platforms.
Key Features
- Triple Modular Redundant voting logic — three redundant channels vote on relay action for maximum safety integrity
- 4 voting relay outputs — each relay output combines redundant channel signals through voting
- Programmable logic — AND/OR voting configurations, time delays, and invert/non-invert relay options via 3500 Rack Configuration Software
- Alarm drive input — accepts alarm signals from any monitor module in the rack
- Turbine trip ready — designed for direct integration into turbine control and emergency shutdown systems
- Front panel LED status — OK, Alert, Danger, and Bypass indicators for rapid diagnostics
- Hot-swappable design — module replacement without powering down the 3500 rack
- API 670 compliant — suitable for applications requiring international machinery protection standards
Technical Specifications
| Parameter | Specification |
|---|---|
| Part Number | 125696-01 |
| Model | 3500/34 Triple Modular Redundant (TMR) Relay Module |
| Module Width | Full-size (1 slot) + external relay hardware |
| Relay Outputs | 4 voting relay outputs |
| Redundant Channels | 3 independent channels per voting output |
| Voting Logic | Programmable AND/OR (2-out-of-3 voting configurations) |
| Relay Type | Electromechanical relay outputs (SPDT) |
| Contact Rating | Refer to datasheet (typically 5 A @ 28 VDC / 120 VAC, resistive) |
| Relay Mode | De-energized-to-alarm or energized-to-alarm (invert/non-invert, programmable) |
| Time Delays | User-programmable per output |
| Power Consumption | Typically 7.0 Watts |
| Operating Temperature | –30°C to +65°C (–22°F to +149°F) |
| Storage Temperature | –40°C to +85°C |
| Relative Humidity | 5% to 95%, non-condensing |
| Mounting | 3500 series rack (19-inch EIA standard) |
⚠️ *Specifications may vary depending on firmware version and relay hardware option. Contact our team to confirm the correct configuration for your shutdown system design.*
Applications
- Steam turbine and gas turbine emergency trip systems in power plants
- Critical compressor train shutdown logic in LNG and petrochemical facilities
- TMR voting protection for offshore and onshore oil & gas platforms
- API 670-compliant machinery protection rack designs
- Safety Integrity Level (SIL) oriented protection architectures for critical rotating equipment
Why Buy From Us?
- ✅ In stock — large inventory of 3500 series modules for same-day dispatch
- ✅ 12-month warranty on every module
- ✅ Tested & verified — each unit inspected before shipment
- ✅ Global shipping — DHL / FedEx / UPS express delivery
- ✅ Technical support — experienced engineers available for configuration and troubleshooting
- ✅ Competitive pricing — contact us for volume discounts and project packages
Frequently Asked Questions (FAQ)
Q1: What makes the 3500/34 different from the 3500/32 or 3500/33 relay modules?
A: The 3500/32 (4-channel) and 3500/33 (16-channel) are standard relay modules that drive one relay per alarm signal. The 3500/34 is a Triple Modular Redundant module — it uses three independent channel outputs and voting logic per relay, making it suitable for safety-critical turbine trip applications where both false trips and missed trips must be minimized.
Q2: How many relay outputs does the 3500/34 provide?
A: It provides 4 voting relay outputs, each backed by triple modular redundant channel logic.
Q3: What is the difference between 125696-01 and related relay P/Ns?
A: The 3500/34 system consists of the TMR relay module in the rack plus external relay hardware. Part number 125696-01 is the commonly referenced P/N associated with this relay module. Contact us with your rack configuration and we will confirm the exact P/N combination you need.
Q4: Can the 3500/34 be configured for 2-out-of-3 voting?
A: Yes. Voting logic (AND/OR combinations), time delays, and relay invert/non-invert behavior are all programmable via the 3500 Rack Configuration Software.
Q5: What is the lead time and warranty?
A: In-stock items typically ship within 24–48 hours. All modules come with a 12-month warranty.
Related Products
- Bently Nevada 3500/32 4-Channel Relay Module
- Bently Nevada 3500/33 16-Channel Relay Module
- Bently Nevada 3500/42M Proximitor*/Seismic Monitor
- Bently Nevada 3500/45 Position Monitor
- Bently Nevada 3500/53 Electronic Overspeed Detection System
- Bently Nevada 3500/15 Power Supply Module
Request a Quote
Need the Bently Nevada 3500/34 125696-01 for your machinery protection or turbine trip system? Contact us today for pricing, availability, and technical documentation.
BENTLY BRAND
| 125760-01 | 133396-01 | 3500/54M |
| 125768-01 | 133819-02 | 3500/60 163179-01 |
| 125800-01 | 135473-01 | 3500/61 |
| 125840-01 | 135613-01-00 | 3500/61-01-01 |
| 2300/20-00 | 3500/64M | 3500/62-03-00 |
Recommended other models
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Bently Nevada 3500/42 140471-01 | 4-Channel Proximitor/Seismic Monitor
Supplies industrial spare parts covering well‑known international brands: ABB, GE, Bently Nevada, Emerson, Honeywell, Schneider, EPRO, Yokogawa, Woodward, Foxboro and Invensys TRICONEX.
We maintain ample stock, offer fast lead times and deliver products with stable, reliable quality.
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