Nidec Mentor MP420A4 / MP420A4R (420A) High-Power DC Drive

Nidec Mentor MP420A4 / MP420A4R (420A) High-Power DC Drive

The Nidec Mentor MP420A4 and MP420A4R are high-performance digital DC drives designed for heavy-duty industrial applications.

 As a cornerstone of the Mentor MP series, the 420A model provides the ultimate combination of motor control precision, robust power delivery, and modern system integration.

Product Introduction

The MP420A4 (2-quadrant) and MP420A4R (4-quadrant regenerative) represent the transition of DC technology into the digital age.

 Built on Nidec’s premier "Control Techniques" platform, these drives are engineered to maximize the life and productivity of DC motors. 

While the standard A4 model handles unidirectional high-torque tasks, the A4R version provides full four-quadrant control, allowing for energy-efficient braking and bidirectional operation.

Technical Parameter Table

Product Advantages and Features

Industry-Leading Field Control: Includes an integrated 20A field controller as standard, supporting intelligent field weakening and flux control for superior open-loop performance.

Galvanic Isolation: A unique, patent-pending feature that isolates control circuits from high-power armature voltages, significantly increasing safety and system reliability.

System Integration Flexibility: Features three universal option slots for Ethernet, Profibus, EtherCAT, and advanced feedback modules (SinCos, EnDAT, etc.).

Standard 5-Year Warranty: Reflecting Nidec’s confidence in its build quality, the MP420 series comes with an industry-best warranty.

SmartCard Backup: Allows for "no-PC" configuration by storing parameters and PLC programs on a portable card for rapid drive replacement.

Unique Product Description

The MP420A4 series is characterized by its "Universal Intelligence." It is the only high-current DC drive that utilizes the same software ecosystem and communication modules as Nidec’s world-leading AC drives.

 This creates a unified automation environment where engineers can manage DC and AC assets using a single toolset, drastically reducing technical overhead and spare parts inventory.

Other Models in the Same Series

The Mentor MP range is designed to cover every industrial power bracket:

MP25A4(R) to MP210A4(R): Smaller Frame 1 units (25A–210A).

MP350A4(R): The 350A predecessor in Frame 2.

MP700A4(R) to MP1850A4(R): Large-scale Frame 2C/2D modules for heavy industry.

Modular Paralleling: Capability to scale up to 7400A for massive mill applications.

Application Cases

Metals & Mining: Controlling large-scale extruders, rolling mills, and wire drawing benches.

Tire & Rubber: Driving high-torque mixers where speed stability under fluctuating loads is essential.

Cranes & Hoists: Utilizing the MP420A4R for precise load control and energy recovery during regenerative braking.

Pulp & Paper: Synchronized section control for high-speed processing lines.

Installation and Maintenance

Mechanical Footprint: The MP420A4 is a Frame 2B drive. It is designed to be a direct physical replacement for the legacy Mentor II series, sharing the same mounting points and terminal positions.

Thermal Protection: Integrated "Intelligent Fan Control" manages cooling based on actual load and temperature, preventing unnecessary dust ingress.

Maintenance: The drive includes sophisticated diagnostics for SCR junction temperature, phase loss, and feedback loss. 

Routine maintenance involves checking the heatsink for blockages and ensuring power terminal torque settings are maintained.

Retrofitting: Use the "CTSoft" migration wizard to easily transfer parameters from older generations of Control Techniques drives to the MP420 platform.

Models available for two or four quadrant (regenerative) operation

25A to 7400A, 24V - 480V / 500V - 575V / 500V - 690V

Optional high-brightness LED or multi-language LCD keypad, simple configuration using plain text

Modular parallel connection for higher power motor operation

12/24 pulse operation to minimize harmonics

IP20 (NEMA 1) protection for size 1. IP10 (open chassis) for size 2A and 2B, and IP00 (open chassis) for size 2C and 2D for easy, low cost installation

Integrated drive and motor protection for:

Over current

Over temperature

Phase loss

SCR/Thyristor junction temperature

Feedback loss

Field loss

Armature open circuit

Internal field controller with intelligent field weakening means that for 90% of applications no additional external controller is required

Frame size 1 to 8A

Frame size 2 to 20A

Flux control for enhanced open loop performance

Optional FXMP25 external field controller for current fields up to 25A

Digital link for field control from Mentor MP or Mentor II

Standalone digital control mode for simple application

Flux control for enhanced open loop performance

Intelligent field weakening

Field forcing – for high dynamic machine reversal

Field reversal – low dynamic machine reversing using two quadrant main stack

Mentor MP has a field control mode for fields requiring greater than 25A

Serial port for Modbus RTU and PC communications

3 Universal option module slots, allowing Mentor MP to benefit from the solutions developed for Control Techniques market leading AC drive technology.

Each option slot allows:

High performance PLC and motion control

Ethernet and Fieldbus communications

Connectivity to additional feedback devices

Additional I/O

Galvanically isolated control

Smartcard for drive parameter back-up and copying, allowing rapid installation and maintenance

Integrated PLC as standard

Standard software features for easy integration

PID controller

Motorised potentiometer

Digital lock (Slave operation from master encoder)

Open loop control using estimated speed advanced processing based on armature voltage and field flux feedback

Closed loop control using

Tacho-generator feedback for connection to traditional DC motor

Incremental encoder feedback for higher accuracy and position control

Optional SinCos, SSI, Hiperface and EnDAT connectivity for high performance applications

High performance control strategy

32 bit microprocessor

35μs current sampling time

Speed controller and ramps update 250μs

Autotune features for armature, field current loops and speed loop

Current ratings

The power ratings for the 480V, 575V and 690V configurations are shown below.

The continuous current ratings given are for a maximum ambient temperature of 40°C (104°F) and an altitude of 1000m (3.300ft). For operation at higher temperatures and altitudes de-rating is required. 

Overload of 150% for 30s is available with ambient temperature of 40°C (104°F) up to a maximum of 10 repetitions per hour.