If you're reading this, you may have found yourself needing three-phase power. Maybe you are opening a new shop or business space, but the building only has single-phase power and your equipment requires three-phase. Maybe that machine tool you found at auction was a great deal until you checked the nameplate. Or maybe you are expanding and the compressor, HVAC system, elevator, pump, or other piece of equipment you need requires power your building simply doesn't have.
These situations are common. Much of the last mile of the U.S. power grid is single-phase, while the equipment that powers businesses and demanding applications is designed for three-phase. CNC machines, air compressors, elevators, irrigation pumps, winery equipment, and oil and gas systems all depend on it. Phase conversion exists to bridge that gap.
Why Your Equipment Is Three-Phase
Three-phase power and three-phase motors grew up together. The grid is three-phase because motors are, and motors are three-phase because the grid is. Either way, serious equipment gets built around it, and a three-phase motor is smaller, more efficient, and more reliable than a single-phase motor of the same horsepower. A single-phase service supplies two of the three voltages your equipment needs. Phase conversion produces the third.
Not All Phase Conversion Is the Same
Three technologies are sold for this: static, rotary, and digital.
A static converter starts your equipment on unbalanced three-phase and then drops out, so it runs single-phase with a significant loss of power and efficiency for as long as it runs. It is suited to a single light load and not to continuous duty.
A rotary converter uses a spinning idler motor to generate the third leg. Once your equipment is up to speed it runs three-phase, with voltage balance that varies with load. The problem is inrush. Every across-the-line start demands several times full-load current, and the generated leg cannot supply it, so the leg collapses and the two pass-through legs carry the start. Scope data on motor starting → That happens on every start, including every cycle of a compressor or pump. Sizing a rotary at roughly double the load is the standard way of working around this.
A digital converter generates and regulates the third leg electronically. Your equipment starts and runs on balanced three-phase, there is no idler to maintain, and the converter is sized to the load rather than to a derating factor. Phase Perfect® is a digital converter.
The Phase Perfect® Industrial Series
The Phase Perfect® Industrial Series is built to make the generated leg indistinguishable from utility power: 98.7% efficiency and voltage imbalance under 2% across the full load range. Sizing is one to one, so a 5 HP machine gets a 5 HP converter with none of the doubling a rotary requires. Nothing spins, so there is nothing to wear out and nothing to maintain over the life of the unit.
That matters in two directions. Voltage sensitive electronics like CNC controls and HVAC or elevator drives get clean, regulated power. Motors that are hard to start, run continuously, or sit somewhere you would rather not pull them from, such as submersible pumps, air compressors, and oil and gas equipment in the field, get balanced three-phase that does not cook their windings. Standby draw is low, so an idle unit costs you almost nothing.
The Bottom Line
Most people run into phase conversion because they have equipment to run and no three-phase service. Whatever you put in now is what that equipment runs on for the next twenty years, at its full rating or derated and unbalanced. Digital conversion supplies balanced three-phase at the rating you paid for, and that is what the Phase Perfect® Industrial Series does.