Phase Converters & Power Factor
Phase Converter Efficiency
Installing a Phase Converter
Rotary Phase Converters
Static Phase Converters
VFDs as Phase Converters
     • Harmonic Distortion
Three-Phase Motors
Phase Converters & Voltage Balance
Phase Converter Applications
     • Submersible Pumps
     • Woodworking Equipment
     • Dual Lift Stations
     • Phase Converters & Welders
     • Phase Converters & CNC Machines
     • Phase Converters & Air Compressors
     • Phase Converters & Elevators
     • Phase Converters & Wire EDM
     • Phase Converters & HVAC
Phase Converters & Transformers
     • Step-up Transformers
     • Buck-Boost Transformers
     • Isolation Transformers
Phase Converter Experts
Digital Phase Converters
Regenerative Power
Three-Phase Power
     • Delta vs. Wye Configured Power
Motor Starting Currents

Phase Converters and Welders


Modern welders typically take the AC power from the input and convert it to DC power through a rectifier to provide a DC voltage for welding.

A static converter or a phase converting VFD should never be used for this type of application. Doing so will almost certainly damage the welder.

A rotary converter can power a welder, but since the output of the welder is adjustable for different welding conditions, the input power demand will change accordingly.  This creates voltage imbalance problems for the rotary converter. Unbalanced voltage supplied to

a three-phase rectifier can damage the rectifier, especially when it operates near its capacity. The unbalance might also effect the consistency and quality of the weld.  Some welders also have a very poor power factor on the input and when powered by a rotary converter, the power factor on the input side of the phase converter will be extremely poor, leading to overloading of the single-phase wire and circuit breaker serving the load.

A digital phase converter is the best phase converter for operating a modern welder.

The sine wave output of the converter is safe for powering a

rectifier input, and the perfectly balanced voltage from no load to full load ensure safe, smooth operation of the welder at all times. Because a digital phase converter has electronic power factor correction, it doesn’t make the power factor of the welder worse, it actually corrects it to unity. This results in a very efficient, utility friendly solution for providing three-phase power to a welder.