Variable Frequency Drives & Digital Phase Converters

Phase Conversion

What is Phase Conversion?

A phase converter is a device that produces three-phase electrical power from a single-phase source, thus allowing the operation of three-phase equipment at a site that only has single-phase electrical service.

The first phase converters were invented nearly one hundred years ago. These were static phase converters, and they have changed little since that time. Over the years, other technologies have been employed as phase converters and hundreds of companies, large and small, manufacture phase converters.

How To Choose The Right Phase Converter

Choosing the right phase converter for an application can be complicated. Phase Technologies prides itself in making this decision as easy as possible. Using the following guide should assist you in selecting the correct phase converter for your application. However, if you need help or have questions please call our expert sales staff for assistance.

When To Use A Phase Perfect® Digital Phase Converter

  • To Simultaneously Power
    Electronics and Motors

    Only the Phase Perfect® digital phase converter, with its patented solid-state technology, provides a safe, clean, three-phase output which is capable of starting and stopping motors across the line while running electronics such as transformers, contactors, circuit boards, lights, and heaters.

  • To Power Multiple Loads

    While a single VFD enables multiple loads to run at one time, they must all be started and stopped together, or control issues may result. However, unlike a VFD, the Phase Perfect® digital phase converter provides the flexibility needed to start, stop and run equipment at different times.

  • Equipment Designed With Internal VFDs

    Equipment designed with internal VFDs shouldn’t be controlled by an external VFD. This type of equipment is not meant to be started and stopped by the source power. While it may seem counterintuitive, a VFD powering another VFD will damage the system.

    For loads such as CNC, HVAC, and elevators, a Phase Perfect® Digital Phase Converter is recommended.

When To Use A Variable Frequency Drive (VFD)

  • For Motor Control

    A VFD starts, stops and controls the speed of motors, as well as communicates with other systems such as sensors, floats, and programmable logic controllers (PLC).

  • As A Soft Start

    A VFD ensures a “true soft start” which means that it won’t allow the motor to exceed its rated run current during start up.

  • For Constant Pressure Control

    A VFD maintains constant system pressure by automatically varying pump speed in reaction to changes in system pressure.

  • If Electronics Are Not Present

    A VFD can ONLY run motor loads. Never connect a VFD to a device that contains electronics such as, but not limited to, transformers, contactors, circuit boards, lights, and heaters.

  • For Pivot Applications

    Phase Technologies is the only company that designs and manufactures a VFD system with an output to run a pumping system and a digital phase converter to run a pivot at the same time. (See the 1LH Series with AUXPOWER™ systems). This VFD system phase converts power, runs a constant pressure system, and provides sinusoidal power simultaneously to efficiently operate a pivot with electronics and GPS.

Phase Converter Technology

There are rotary phase converters, variable frequency drives (VFD) adapted as phase converters and the newest technology, digital phase converters. This can make the search for one a confusing process. This technical white paper, ‘A Comparison of Phase Converter Technologies’ is a good resource if you want a scientific, detailed explanation of phase converter technologies.

Phase converters have been widely used because three-phase service from the electric utility is not available in all locations. Three-phase service is generally expensive to install and may not be available at any price in remote locations or residential neighborhoods. It is more expensive than single-phase service because it requires more wires, more high voltage transformers and a different service panel. It is also common for the utility to charge a higher monthly service fee for providing three-phase service.

There are dramatic and important differences among phase converters in terms of price, power quality, voltage balance, efficiency, versatility and ease of installation.


Digital Phase Converters

Phase Technologies revolutionized phase converter technology by utilizing proprietary software in a powerful microprocessor to control solid state power switching components. This microprocessor, called a digital signal processor (DSP), monitors the phase conversion process, continually adjusting the input and output modules of the converter to maintain perfectly balanced three-phase power under all load conditions.

Like rotary and static phase converters, a digital phase converter generates a third voltage, which is added to L1 and L2 of single-phase service to create three-phase power. However, that is where the similarity ends. A process called double-IGBT conversion generates the third voltage. Double conversion means that AC power from the utility is converted to DC, then back to AC. The power switching devices used in this process are insulated gate bipolar transistors (IGBT).

The solid state design results in a relatively small package with no moving parts except for small cooling fans. The converters are very efficient, operating at 95-98% efficiency. When the converter is energized with no load, it consumes very little power.

See Phase Technologies’ Digital Phase Converters


Cost Savings

Calculate Your Own Cost Savings

Formula for Phase Perfect®

Cost Savings = Idle Time Savings + Run Time Savings

Idle Time Savings = Idle Time × Total Hours × (0.6 × Running Amps × Volts - Phase Perfect Watts) × Cost per KWH

Run Time Savings = Run time × (Volts × Amps × 1.734) × ((0.97 - 0.7) / 1000) × Cost per KWH