Description
1. At-A-Glance Executive Brief
- Model: MRI4
- Brand: Woodward
- Part Type: Digital Multi-Functional Protection Relay
- Lifecycle Status: Active / Legacy Support Transition
- Weight: Approx. 2.1 kg
- Core Protocol: Modbus / IEC 60870-5-103 communication interfaces
2. Technical Introduction
Plant engineers dealing with aging switchgear often scramble when a legacy feeder protection relay fails, threatening plant-wide electrical distribution reliability. The Woodward MRI4 integrates into medium-voltage switchgear cubicles to deliver precise overcurrent, earth fault, and system monitoring functions without requiring an immediate, capital-intensive control room upgrade. This numerical relay processes current and voltage inputs through internal DSP architecture, tripping breakers safely within programmed fault-clearance parameters.
3. Core Technical Specifications
- Manufacturer: Woodward
- Product Series: MR Line / MRI4
- Device Function: Multi-functional overcurrent and protection relay
- Auxiliary Power Supply: Wide-range universal DC/AC power supply
- Analog Inputs: 3-phase current transformers, earth fault input, voltage inputs
- Binary Inputs/Outputs: Configurable relay outputs and opto-isolated inputs
- Communication Port: RS485 / RS232 front and rear ports
- Mounting Type: Flush panel mounting or 19-inch rack adapter
- Enclosure Rating: IP54 front face protection
4. Field Engineer’s Tech Notes
- CT Sitter and Burden Calculations: Verify that secondary current transformer wiring matches the 1A or 5A configuration jumper settings on the terminal block before energizing the switchgear. Mismatched CT inputs lead to severe measurement distortion and nuisance tripping during normal motor starting currents.
- Firmware and Parameter Backup: Always pull a configuration backup using the corresponding configuration software via the front communication port before swapping out a failing unit. Uploading the exact parameter file prevents mismatch errors regarding pickup thresholds and inverse-time curve selections.
5. Adaptive QA & Testing Protocol
Our bench testing protocol for protective relays involves precision injection test sets. For this numerical relay, technicians execute secondary current and voltage injection to verify pickup accuracy across multiple inverse-time curves, test binary output contact closures, and validate Modbus communication handshakes. Insulation resistance checks are performed across all isolated terminals. Test reports and calibration certificates are available upon request.
6. Buyer’s FAQ
- What is the warranty period for this protective relay? All units carry a 12-month replacement warranty covering component failure under normal operating conditions.
- Are these units shipped with configuration software included? The hardware is supplied standalone. Configuration files must be transferred from your existing system backup or engineered via the manufacturer’s software utility.
- How fast can this part be dispatched for emergency outages? Stocked items ship same-day via priority air freight to ensure minimal interruption to plant power distribution.
