SK5401 - Variable speed drive - CONTROL TECHNIQUES

Control Techniques SK5401 Frequency Converter, DIGIDRIVE SK

The reference frequency converter SK5401 belongs to the DIGIDRIVE SK family, also referred to as Commander SK, developed by Control Techniques. Intended for controlling three-phase induction motors, it covers a wide range of industrial applications, from conveying to ventilation, including pumping and continuous processes. The SK5401 architecture is built around two microprocessors, one of which is a dedicated DSP for PWM modulation with adjustable switching frequency, enabling refined control dynamics, optimized low-speed torque availability and repeatable setpoint accuracy. The design provides integrated I/O for direct wiring to a programmable logic controller and HMI, as well as configurable motor protection and safety parameters to improve reliability in industrial environments. The drive can be mounted in a control cabinet or on machinery, supplied as a replacement or for retrofit purposes, helping reduce downtime and extend equipment service life.

Technical specifications

• Manufacturer reference : SK5401
• Range : DIGIDRIVE SK / Commander SK
• Manufacturer : Control Techniques
• Type : AC variable speed drive for three-phase induction motors
• Supply voltage : depending on series variant, 200–240 V, 380–480 V, 500–575 V or 500–690 V three-phase, 50/60 Hz
• Rated power : depends on the chosen configuration within the range, refer to the nameplate
• Rated output current : dependent on the configured power and operating conditions
• Output voltage : 0 to mains voltage in three-phase, generated by PWM modulation
• Control modes : V/Hz and sensorless open-loop vector control, depending on series configuration
• Switching frequency : adjustable via parameter, driven by DSP to optimise noise, losses and signal quality
• Cooling : fan controlled by heatsink temperature, speed modulated for extended life and reduced consumption
• Integrated I/O : digital inputs for start, stop and direction, analog inputs (voltage or current) for speed reference, status output relays
• Protection functions : monitoring of overvoltage, undervoltage, overtemperature, current limiting and configurable motor thermal protection

Overview of the DIGIDRIVE SK range

The DIGIDRIVE SK series from Control Techniques is designed for general and mid-range drive applications where reliability, commissioning flexibility and compactness are priorities. Well known in industrial maintenance, the range offers several mechanical sizes and power bands, with supply variants tailored to common industrial networks. It is suitable for new installations as well as replacements of older drives to secure operational continuity.

• Versatile speed control : V/Hz and sensorless open-loop vector control, configuration of minimum and maximum speeds, acceleration and deceleration ramps, start/stop management based on setpoint
• Options and adaptability : compatibility with series accessories depending on version, EMC filters and mounting solutions for cabinet or machine integration

The SK5401 follows this standardisation and interchangeability approach. It is typically supplied as a bare drive, with the power terminal block separate from the control terminal block. This approach simplifies rewiring during a standard exchange while preserving existing control logic driven by a programmable logic controller or numerical controller.

Industrial applications

The SK5401 addresses common needs for speed regulation and energy optimisation in continuous and intermittent processes. Its digital signal processing, integrated I/O and protection features make it a suitable choice for environments with varied operating constraints.

• Conveyors and material handling : assembly lines, sorting, workstation feeding, roller synchronisation
• Pumping : flow and pressure adjustment on process water networks and utilities
• Ventilation and air handling : fans, extractors, cooling towers, optimisation of operating point
• Packaging : drives for forming, feeding and discharge conveyors
• General processes : mixing, dosing, bulk transport, workshop utility applications

Integration and communication

The SK5401 drive interfaces easily with programmable logic controllers and numerical control systems via its logic inputs for start, stop and direction, as well as its analog inputs for speed reference. Status output relays provide simple feedback to the PLC, aiding diagnostics and supervision. Depending on the versions and options available in the series, communication cards can be added to fit existing automation architectures.

Commissioning is carried out via the local operator panel and the manufacturer's software tools. The main accessible parameters include acceleration and deceleration ramps, speed limits, control and reference sources, stop and restart strategies, as well as motor protection levels. The temperature-controlled fan helps maintain sustained load capability while limiting noise and consumption under light duty.

Availability and warranty

This Control Techniques SK5401 drive is offered by Standard Exchange Industry as reconditioned supply or as a standard exchange, and also as a repair service when appropriate. Each unit supplied is bench-tested to validate speed control, thermal behaviour, protection functions and correct operation of the I/O. Shipping is arranged within 24 to 72 hours to many countries, with a warranty ranging from 6 to 24 months depending on the selected service. To secure your choice, our technical team can verify the reference's compatibility with your motor, supply voltage and control logic, and propose an equivalent solution within the DIGIDRIVE SK series if necessary. The product is delivered without motor, with separate power and control terminal blocks. Before ordering, we invite you to confirm the voltage range, target motor power, required I/O and any options to ensure integration without modification of your automation.