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

Static Phase Converters


The simplest type of phase converter is generically called a static phase converter and has been in use for nearly one hundred years. This device typically consists of one or more capacitors and a relay to switch between the two capacitors once the motor has come up to speed. These units are comparatively inexpensive. They make use of the idea that a three-phase motor can be started using a capacitor in series with the third terminal of the motor.  It then runs with essentially two of the three windings powered.

It is almost guaranteed that a static phase converter will do a poor job of balancing the voltages on the motor.

Unless motors operated on static converters run only for short periods or

deliver significantly less than half of their rated output, they will be damaged from overheating. Some manufacturers of static converters make a simplistic statement that since two of the three windings are powered, the motor will be capable of generating two-thirds its rated power.  This is misleading and could lead

to damage of the motor. If the motor were loaded anywhere near two-thirds its capacity, it would be permanently damaged in short order.

The only good thing that can be said of static phase converters is that they are inexpensive. They can only operate motors, and only single-motor loads. The motors must be limited to light loads and intermittent use.