ALSTOM MC15-M2 Motor Control Unit

Overview

The MC15-M2 belongs to ALSTOM’s range of digital motor protection relays, tailored for critical motor applications in industries such as power generation, oil & gas, and water treatment. It ensures reliable motor starting, running, and stopping sequences while providing advanced protection against electrical and mechanical faults. The unit is housed in a robust drawout case suitable for panel mounting.

Key Features

• Protection Functions: Thermal overload (49), locked rotor (48/51LR), short-circuit (50/51), earth fault (50N/51N), undercurrent (37), negative phase sequence (46), and start-up monitoring.

• Motor Management: Automatic reset, number of starts limitation, restart inhibit, and motor run hours counter.

• Measurement: Phase currents, thermal capacity, motor runtime, and trip counters.

• Inputs/Outputs: 6 digital inputs, 4 output relays (programmable), and 2 analog outputs (4-20 mA).

• Communication: RS485 Modbus RTU (standard), optional Profibus DP or Ethernet.

• Display: Graphical LCD with backlight, showing current values, settings, and fault records.

• Self-Monitoring: Continuous supervision with watchdog output.

Technical Specifications

• Auxiliary Supply: 24-250 V DC / 100-240 V AC,<15 W.

• Current Inputs: 1 A or 5 A rated, accuracy class 0.5.

• Thermal Model: Based on IEC 60255-8 and real-time motor cooling time constants.

• Operating Temperature: -10°C to +60°C.

• Dimensions: 177 x 266 x 210 mm (4U height).

• Protection Class: IP54 front, IP20 rear.

Functional Description

The MC15-M2 continuously monitors motor currents to calculate thermal capacity using an adaptive model that considers positive and negative sequence currents. It provides pre-alarm and trip outputs when thermal limits are exceeded. Locked rotor protection is enabled during start-up, while running overload protection uses inverse time curves. The relay also includes start-up supervision to detect excessive start time or stall. All events are time-stamped and stored in non-volatile memory.

Applications

• Protection of pumps, fans, compressors, and conveyors.

• Critical motor drives in power plants and refineries.

• Mining and mineral processing equipment.

• HVAC systems with large chillers.

Configuration and Software

The relay is configured via front keypad or using ALSTOM’s MC-Soft software, which allows setting adjustment, disturbance analysis, and firmware updates. Communication protocols enable integration into SCADA and DCS systems. The unit also supports DNP3 and IEC 60870-5-101/104 protocols.

Certifications

• CE marked, UL and CSA listed.

• Complies with IEC 60255 and IEEE C37.90 standards.

• Marine type approvals (ABS, DNV) on request.

Note: This document provides technical information only; for ordering and installation, refer to the official ALSTOM MC15-M2 manual.