Home > Phase Converter Basics > Converter Types: Is Rotary or Static for You?

Is Rotary or Static for You?

Rotary 3-phase converters are the most flexible and reliable type of phase converter. They produce true 3-phase power to run any type of load or combination of motors. For this reason, Kay Industries recommends rotary phase converters for most applications requiring a phase converter.

Static 3-phase converters do not produce true 3-phase power. In fact, static phase converters are little more than electric rope starters. Unlike a rotary phase converter, static phase converters cannot balance the load between the three legs after the motor has started. As a result, static 3-phase converters never allow your motor to develop full horsepower. Static phase converters are thus suited only for small-horsepower, single-motor applications. In addtion, they cannot be used for heaters or rectifier loads.

Consider a static 3-phase converter only if your application

• Starts quickly. If your application requires a long acceleration time, you'll need a rotary phase converter.
  
• Starts infrequently (less than four times in an hour).
  
• Runs at less than 70% of its nameplate horsepower. Full nameplate output for extended periods is only possible with a rotary phase converter.
  

Check the table below for more comparisons between rotary and static phase converters. If you still aren't sure which 3-phase converter type is right for you, fill out our selection worksheet, and we will be happy to make a recommendation.

Feature	Rotary	Static
Single motor loads	Yes	Yes
Multiple motor load	Yes	No
Rectifier & heat loads	Yes	No
Load output	100% of NP rating	60-80% of NP rating
Limits on load starts	None	6 per hour
Long term reliability	Very High	Adequate
Variable load range	High	Limited
Relative cost	High	Low
Efficiency at full load	>95%	99%
HP range	1-500	½-20
Maintenance Requirements	Some but minimal	None

If a static phase converter is right for your application, the MiniPhase Static 3-Phase Converter is the best you can buy, it is built with the same attention to engineering quality and comes with the same service and documentation that has made Phasemaster Rotary Converters the industry leader.