Frequently Asked Questions

What is the difference between an inverter and a VFD?

There is no difference, just different terminology. Variable Frequency Drive (VFD) is the technical term; inverter is what everyone calls them in practice.

Both convert fixed mains frequency into a variable output to control motor speed. Whether you see an Invertek Optidrive E3 labelled as an inverter or VFD, it performs the same function.

How do I select the right VFD for my motor?

Check your motor nameplate for kW rating, voltage, and phase type first. Match these exactly to VFD specifications - a 2.2kW motor needs at least a 2.2kW drive.

Environmental conditions determine enclosure rating: IP20 for clean panels, IP66 for washdown areas. Application type matters too - pumps need different control modes than fans or conveyors.

Why match the voltage ratings between the VFD and the motor?

Mismatched voltages destroy equipment rapidly - a 400V drive outputting to a 230V motor burns windings, and 400V motors on 230V drives have insufficient torque and overheat.

Supply voltage must also align: UK three-phase runs 400V, single-phase uses 230V. The Optidrive E3 three-phase accepts 380-480V input, covering standard UK industrial supplies perfectly.

Can a single-phase VFD drive a three-phase motor?

Not properly — you'll get poor performance and early failure. Single-phase drives output single-phase power regardless of the motor type connected.

Some converters claim to run three-phase motors from a single-phase supply but deliver reduced power and reliability. Buy the right equipment initially instead of bodging incompatible combinations.

What are the benefits of using a VFD?

Energy savings pay for drives quickly — running pumps and fans at 80% speed uses half the power. Soft starting eliminates mechanical shock and electrical spikes during motor startup.

Process control improves dramatically with variable speed instead of throttling valves or dampers. Reduced wear on mechanical components extends equipment life significantly beyond fixed-speed operation.

Single-phase inverter vs three-phase — what's the difference?

Power capacity separates them — single-phase handles up to 3kW on a 230V domestic supply. Three-phase systems manage much larger loads using 400V industrial power, with better efficiency throughout.

Installation differs too: single-phase plugs into standard sockets, whilst three-phase needs proper industrial wiring. Cost and complexity increase with the three-phase but so does capability and reliability.

Where can I purchase high-quality VFDs?

RJW Motors and Inverters stock Invertek Optidrive E3 and Commander C200 ranges in both single and three-phase versions. Ring 0800 999 0200 for expert sizing guidance.

Download technical data from our website. Email sales@rjweng.com with your motor details for accurate quotations and availability.