Description

Not for real photos. All pictures are for reference only.

Product Overview

The MT91-ARC MT-91-ARC FP A MT91 is a compact arc flash protection unit designed for medium and low‑voltage switchgear. It combines fiber‑optic light sensing and overcurrent supervision to detect internal arc faults and issue rapid breaker tripping commands, limiting arc energy and preventing severe equipment damage and personnel hazards. The integrated front panel HMI features an LCD display and membrane keypad for local setup, fault review, event logging and sensor calibration. It supports multiple fiber sensor loops and can be deployed in standalone or coordinated busbar protection schemes. Widely used in power substations, data center distribution boards, mining and petrochemical switch rooms, this legacy relay remains a critical spare for existing arc protection retrofits.

Technical Specifications

• Brand: ABB
• Model: MT91-ARC MT-91-ARC FP A MT91
• Warranty: One Year
• Condition: 100% New & Original
• Input/Output: Fiber optic sensor inputs; current transformer monitoring inputs; configurable trip and alarm relay outputs
• Operating Temp: -20°C to +60°C
• Communication: RS485 serial port, supports Modbus RTU for SCADA integration
• Auxiliary Supply: 18–30 VDC, nominal 24 VDC
• Trip Contacts: 5 A at 250 VAC / 30 VDC
• Detection Principle: Combined light + overcurrent confirmation
• Operation Time: Ultra-fast detection and trip sequence, sub‑millisecond light response
• HMI: Monochrome LCD, function keys, status and fault LEDs
• Mounting: Front panel flush mount for switchgear door
• Enclosure Rating: Front face IP54; rear IP20
• Logging: Stores arc fault records, timestamps and sensor diagnostics
• Certifications: CE, IEC 60255 compliant