SK3401 - Variable speed drive - CONTROL TECHNIQUES

Control Techniques SK3401 Variable Frequency Drive - DIGIDRIVE SK

The SK3401 variable frequency drive is part of the DIGIDRIVE SK series from Control Techniques (Leroy Somer). Designed to control three-phase induction motors, it meets the needs of maintenance teams and system integrators looking for reliable speed and torque regulation in general industrial applications. The DIGIDRIVE SK range is known for its compact size, straightforward parameter setup and robustness in production environments. The SK3401 operates on a three-phase supply, class 480 V AC, and delivers up to 18.5 kW, positioning it for medium to high power drives. The unit covers speed variation requirements for conveyors, pumps, fans and processing machinery, with configurable ramps, integrated protections and adaptable I/O logic for seamless integration into PLC-controlled architectures.

Technical specifications

• Manufacturer reference : SK3401
• Range : DIGIDRIVE SK
• Manufacturer : Control Techniques
• Type : Compact AC variable frequency drive for three-phase induction motors
• Supply voltage : Three-phase class 480 V AC
• Maximum motor power : 18.5 kW, approx. ≈ 25 CV / 25 HP
• Output voltage : Three-phase for induction motor, adapted to the speed setpoint
• Basic functions : Start/stop, configurable acceleration and deceleration ramps
• Thermal protection : Monitoring and limiting to protect the drive and the motor
• Cooling : Automatic control of the internal fan speed according to heatsink temperature
• Controls and setpoints : Adjustment via analog and digital inputs, adaptable control logic
• Parameter interface : Simplified access to commissioning and operational parameters
• Extensions : Optional modules available depending on configuration to expand I/O and communications

DIGIDRIVE SK range overview

The DIGIDRIVE SK series from Control Techniques was developed to provide fast implementation and reliable operation on standard AC drives. Targeted at general applications, it covers speed variation for induction motors with a compact footprint and a clear interface for maintenance. The design prioritises energy efficiency by continuously adapting motor speed to load while ensuring service continuity through integrated protection functions and careful thermal management.

• Speed control for induction motors : Precise adjustment of frequency and voltage to meet process setpoints, with the possibility of overspeed where the application and motor allow.
• Modular architecture : Expandable by modules in the range to adapt the drive to panel topology and I/O and communication requirements.

The SK3401 follows this approach by combining power, simple commissioning and compactness. It is a relevant solution for plant upgrades and for minimising downtime during emergency replacements, while remaining compatible with common control practices in industrial automation.

Industrial applications

This Control Techniques variable frequency drive fits into many industrial environments where speed accuracy and operational reliability are required. It is particularly suitable for variable-rate lines and utilities where flow or pressure modulation is needed.

• Conveying and material handling : Speed regulation for conveyor belts, drive rollers and synchronized transfers on assembly lines.
• Pumping and fluid handling : Adjustment of operating point for energy optimisation and hydraulic protection.
• Industrial ventilation and HVAC : Airflow modulation on fans and exhausters to match actual demand.
• Process machinery : General drives for packaging lines, assembly machines and auxiliary equipment.
• Unservocontrolled multi-axis drive sections : Coordination of multiple induction motors controlled by a PLC.

Integration and communication

Integration of the SK3401 into an automation architecture is straightforward thanks to configurable I/O logic and the option to add expansion modules from the range. Speed setpoints and run commands can be provided by a PLC, analog inputs or discrete contacts. Local configuration is simplified by a clear interface, allowing ramps, frequency limits and protection thresholds to be defined in a few steps, which reduces commissioning time and eases maintenance interventions.

For CNC-driven installations, the drive can be integrated as a non-servo axis where speed variation meets the process needs. When data exchange is required, the DIGIDRIVE SK range offers optional cards depending on available configurations to ensure consistent communication with the control system. This modular approach prevents oversizing the power electronics and allows precise adaptation of connectivity to the specification. Note that the SK3401 is not a servo drive and is dedicated to AC induction motors, ensuring appropriate sizing for utilities and standard drives.

Availability and warranty

The Control Techniques SK3401 variable frequency drive is offered by Standard Exchange Industry as refurbished, exchange or repaired units. Each unit supplied is bench-tested and delivered with a warranty, with typical shipping times of 24 to 72 hours to over 120 countries. In the event of a line stoppage, our technical team supports you with electrical compatibility checks, model selection and preparation of a replacement solution. Depending on the chosen service, the warranty can extend up to 24 months. This approach aims to secure your operational availability while controlling total cost of ownership. If you are unsure between several references in the DIGIDRIVE SK range, we help you compare supply voltage, target motor power in kW and HP, control wiring and any communication requirements to determine a configuration that matches your specification.