Does a Rotary Phase Converter Start Automatically?
It depends on the series you choose. Phoenix Phase Converters offers two control options:
- NL Series (Auto-Start): The converter starts automatically when single-phase power is applied — no button required. The idler motor energizes, builds up three-phase power, and your equipment is ready to start. This is the most common choice for machine shops.
- PL Series (Push-Button): Includes a front-panel start/stop button. You press start to energize the converter, then start your equipment. Choose PL if you want manual control or need T1/T2 timer terminals for a magnetic starter circuit.
Can I Add Automatic Controls?
Yes — automatic controls can be added to allow unattended or remotely triggered starts. Options include:
- Timer-based start: A time-delay relay starts the converter on a schedule
- Pressure-switch start: Used with air compressors — the converter starts when the compressor pressure switch calls for power
- NLA AutoLink: Phoenix's built-in automatic control system designed specifically for air compressors and HVAC — manages inrush current digitally
Starting Sequence Best Practice
- Apply single-phase power to the converter (NL auto-starts; PL: press Start)
- Wait 2–3 seconds for the idler motor to reach full speed
- Start your three-phase equipment normally
Never apply a heavy load to the converter before the idler motor is at full speed — this can cause a voltage drop and trip the breaker.
Have more questions? Talk to an engineer.
Free sizing help — no pressure. Made in Phoenix, AZ. Lifetime warranty.
Shop Phase Converters →Related Articles
Auto-Start — FAQ
What is the startup time for the NL Series?
2–3 seconds from power application to full idler speed. After that, your equipment can be started normally.
Will the converter restart automatically after a power outage?
Yes — NL Series converters restart automatically when utility power is restored, since they start whenever single-phase power is applied. Ensure your equipment is safe to auto-restart before relying on this behavior.
Can I add a timer to the converter to schedule startup?
Yes — a standard time-delay relay on the single-phase input circuit will control when the NL Series converter starts. This is a common setup for shops that want the converter running before staff arrive.
Related Articles
- How to Size a Rotary Phase Converter
- What Is a Rotary Phase Converter?
- Rotary vs Digital Phase Converters
- Phase Converter FAQ
Questions? Talk to an engineer.
Free sizing help. Made in Phoenix, AZ. Lifetime warranty on every unit.
Shop Phase Converters