Control Techniques SPMD1424 Unidrive SPM Power Inverter Unit

Module Feature

SPMD1424 is the high-power inverter module of Nidec Control Techniques Unidrive SPM modular drive platform. It only works from shared DC bus and must be matched with SPMC rectifier unit to form a complete drive group. Rated continuous output current is 290A, peak overload current up to 350A, corresponding to 160kW normal duty and 200kW heavy duty at 400V AC class. It integrates dynamic brake chopper circuit for regenerative energy dissipation, requiring external brake resistor. Control modes include V/F open loop, sensorless vector, closed-loop flux vector and servo position control, compatible with induction motor and permanent magnet servo motor. Multiple expansion slots support encoder feedback cards and industrial fieldbus options such as Profinet, EtherCAT. Forced air cooling design with temperature monitoring, comprehensive hardware protection for heavy cyclic load. Widely used for metallurgical equipment, overhead cranes, twin-screw extruders, large centrifugal fans and water pumps.

Working principle

Stable DC voltage supplied by the front-end rectifier enters the inverter module. IGBT power stack converts DC power into adjustable frequency and adjustable voltage three-phase AC to drive the motor. Position and speed feedback signals from motor encoder are continuously sampled for closed-loop regulation. During rapid deceleration, regenerative energy raises DC bus voltage; once threshold exceeded, internal chopper activates to discharge surplus energy on external brake resistor. Drive exchanges setpoint, status and fault information with host PLC or motion controller via fieldbus.

Onboard components

IGBT power assembly, high-speed current sampling circuit, brake chopper power stage, main DSP control PCB, backplane interface, dual option card expansion slots, cooling fan group, DC bus and motor output terminal lug block.

LED indicators

Front panel LEDs for power ready, drive enable, fault and bus communication activity; detailed alarm codes and runtime parameters can be checked with the dedicated Unidrive keypad.

Hardware self‑diagnosis

Power-on self-test detects DC bus over/under voltage, output overcurrent, IGBT short circuit, internal over-temperature, fan stall, encoder signal loss and option card communication failure. Fault codes and event logs are saved in drive memory.

Programming software

Control Techniques Unisoft software for parameter configuration, motor auto-tuning, fault waveform capture and firmware upgrade.

Electrical & Process Parameters

Model:SPMD1424 Brand:Nidec Control Techniques Series:Unidrive SPM Device type:DC Input Inverter Module Rating:160kW normal / 200kW heavy duty Continuous output current:290 A Peak output current:350 A DC bus range:462~713 VDC Cooling:Forced air cooling Brake circuit:Built-in brake chopper Function:Variable speed and closed-loop position control for heavy-duty asynchronous and permanent magnet servo motors

Mechanical & Structure

Mounting:Cabinet backplane rack mounting Protection class:IP20 Housing:Metal power chassis

Environmental

Operating temperature:0℃ ~ +40℃ full load, power derate above 40℃ Storage temperature:-40℃ ~ +85℃ Ambient humidity:5~95% non‑condensing Certification:CE, IEC61800-3 compliant Status:Control Techniques original SPM spare inverter

Installation

Install in well-ventilated control cabinet and pair with compatible SPMC rectifier. Connect DC bus cable, three-phase motor power cable and brake resistor wiring. Install feedback or fieldbus option cards as required. Run motor identification and current loop auto-tune via Unisoft. Verify emergency stop, overload protection and brake function before commissioning. Keep fan and air inlet filter cleaned regularly.

Interface

DC bus input terminals, U/V/W motor output terminals, brake resistor terminals, option card slots, encoder feedback port, 24V auxiliary control terminals.

Diagnostic

Overcurrent trip: Motor winding insulation breakdown, power cable short circuit or mechanical jamming. DC bus overvoltage: Missing brake resistor, chopper circuit fault or fast deceleration without regenerative rectifier. Over-temperature fault: Fan malfunction, blocked air duct or continuous heavy overload operation. Option card communication loss: Loose card seating, incompatible firmware or backplane contact fault.

Product BriefNidec Control Techniques SPMD1424 Unidrive SPM modular inverter, 160kW / 200kW rating, 290A continuous output, DC bus powered, built-in brake chopper, multi control modes and expandable fieldbus, used for crane, extruder, large fan and pump heavy-duty motor speed and position regulation.