We’re often asked about the best way to convert single-phase power to three-phase—specifically, whether to use a rotary or static phase converter. While both have their place, understanding their differences is key to selecting the right solution for your needs.

⚡ Static Phase Converters: Compact but Limited

Static converters are popular for their low cost and small footprint. However, their functionality is quite limited:

• They can only start and run one motor at a time, and even then, only at reduced power.
• They’re not suitable for powering battery chargers, welders, heaters, variable speed drives, or other complex loads.
• Each motor requires its own static converter, making them impractical for multi-machine setups.

Technically speaking, static converters aren’t true phase converters. According to Miniphase Static Converter’s website, they use capacitors and relays to momentarily simulate a third phase—just enough to start the motor. Once running, the motor operates on single-phase power, which means one of its windings is inactive. As a result, the motor delivers only about two-thirds of its rated horsepower.

This reduced performance may be acceptable for small machines under 10HP, such as drill presses, lathes, or mills, especially when full power isn’t needed continuously.

🔄 Rotary Phase Converters: Versatile and Powerful

Rotary converters, while larger and more expensive, offer far greater capability:

• They generate a true three-phase sine wave, enabling motors to run at full nameplate horsepower.
• They can power multiple machines simultaneously, including those with demanding or sensitive loads.
• They’re ideal for feeding three-phase distribution panels, supporting entire workshops or facilities.

When properly sized, Phasemaster rotary converters deliver consistent, reliable power without any loss in capacity—making them the preferred choice for industrial applications and multi-load environments. Now you know the differences when choosing Between Rotary and Static Phase Converters.