The Driller
  • Sign In
  • Create Account
  • Sign Out
  • My Account
  • NEWS
  • CLASSIFIEDS
  • EQUIPMENT
  • SAFETY
  • VIDEOS
  • EDUCATION
  • SOURCEBOOK
  • EVENTS
  • SUBMIT
  • ABOUT
  • SIGN UP
cart
facebook twitter linkedin youtube
  • NEWS
  • Water
  • Geothermal
  • Construction
  • Environmental
  • Mining
  • All Industry News
  • EQUIPMENT
  • Rigs & Heavy Equipment
  • Consumables
  • Pumps
  • Featured Products
  • VIDEOS
  • Newscast
  • Drill Talks
  • Ask Brock
  • Emerging Drillers
  • EDUCATION
  • Drilling Business Insights
  • Reference Desk
  • Sponsored Insights
  • EVENTS
  • Conferences & Demo Days
  • Newscast LIVE
  • SUBMIT
  • Drillers @Work
  • ABOUT
  • Contact
  • Advertise
The Driller
search
cart
facebook twitter linkedin youtube
  • Sign In
  • Create Account
  • Sign Out
  • My Account
The Driller
  • NEWS
    • Water
    • Geothermal
    • Construction
    • Environmental
    • Mining
    • All Industry News
  • CLASSIFIEDS
  • EQUIPMENT
    • Rigs & Heavy Equipment
    • Consumables
    • Pumps
    • Featured Products
  • SAFETY
  • VIDEOS
    • Newscast
    • Drill Talks
    • Ask Brock
    • Emerging Drillers
  • EDUCATION
    • Drilling Business Insights
    • Reference Desk
    • Sponsored Insights
  • SOURCEBOOK
  • EVENTS
    • Conferences & Demo Days
    • Newscast LIVE
  • SUBMIT
    • Drillers @Work
  • ABOUT
    • Contact
    • Advertise
  • SIGN UP

Tech Topics: Phase Converters: Run a Three-phase Pump on Single-phase Power

By Bob Pelikan
March 1, 2009

Consider this scenario. You go to a flea market and spot an electric motor that looks similar to the one on the wash-down pump in your barn that is starting to make noise. You know that a new motor would cost way more than what this guy is asking for his “slightly used and in good shape” motor, so you buy it. You get it home, and in the process of installing it, you find out that it is a three-phase motor and you only have single-phase power on the farm. You call the utility, and are told that it will be glad to bring in three-phase power from the road for about $15,000, but you will have to wait 6 months because it is a little backed up. What to do?

This is the perfect place to use a phase converter, a device that converts single-phase power to three-phase power. Phase converters come in various shapes and sizes, costing from a few hundred dollars to many thousands, depending on the horsepower rating and type. The phase converter will artificially generate the third leg of a three-phase system from the two leads of a single-phase system.

There are three basic types – static phase converters, rotary phase converters, and solid-state phase converters. There is a forth option which can be used for motor applications – a VFD.

Static Phase Converter

The static units consist of a several capacitors, and often a transformer, sized to the amp draw of your pump motor, to generate the third leg of three phase power. They have been around for a long time, and are the least expensive of the three types. Their advantage is price, and their disadvantage is that they do not provide as closely balanced power as the more expensive units do.

Rotary Phase Converter

The next least expensive units look like an electric motor with a large electrical box attached to the side, which houses the capacitors. The capacitors generate the third phase, and the motor, called an idler motor, cleans up and balances the power. With a rotary phase converter, you can run more than one pump at a time, as long as you do not exceed the maximum capacity of the unit, and the power is balanced better than with a static phase converter.

Solid-state Phase Converter

For applications that require stricter control on the power, solid-state phase converters are the best. They have the advantage of providing very clean power with no harmonics or distortion. They are very efficient, and operate in conjunction with the load motor at nearly unity power factor. They can power multiple loads, and can be located remotely from the load. Some pump installers use them in situations where there already is three-phase power available, but it is so far out of balance that it will not safely run a pump. In this case, a solid-state phase converter is hooked to two legs of the three-phase power, and the pump gets perfect three-phase power from the converter.

Variable Frequency Drives as Phase Converter

Although variable frequency drives (VFDs) are designed primarily to control the speed of AC motors, they can be adapted to function as phase converters. They have the added advantage of allowing you to control the speed of the pump to match the load (see Figure 4).

Problems can arise when using VFDs as phase converters if:

1. They are used to power loads other than motors – we’re fine here.
2. There are multiple loads on the VFD – not a problem for pump applications.
3. The motor needs to provide braking action – not a problem for pump applications.
4. The distance between the motor and the VFD is appreciable – can be an issue with submersible applications, but with proper filtering, usually not a deal killer.
5. The current drawn by the VFD is large compared to the rating of the utility step-down transformer – usually not an issue.

When VFDs are used as phase converters, the drive must be de-rated. Typically, it is necessary to double the size of the drive to the load. 

A precaution: Regardless of what type of phase converter you choose, static, rotary, solid-state or VFD, make sure the unit has enough capacity to start your motor. Remember that the starting current drawn by an electric induction motor can be six or more times full load amps (FLA). Some 10-HP phase converters only will power a 10-HP motor if it is started without a load, and it may take a 15-HP, or even 20-HP, unit to start your motor under load. Consult the pump, motor and/or phase converter manufacturer for information on starting recommendations.

If you have access to the Internet, there is a ton of technical and supplier information on phase converters. Also, check with your local pump distributor. He may well have a source of phase converters, and offers the advantage of being there for you if there is a problem.

Next month, we will continue our series on the electrical side of pumped water systems with a look at three-phase control panels. ’Til then…  
ND

Share This Story

Looking for a reprint of this article?
From high-res PDFs to custom plaques, order your copy today!

Bob is a regular contributor to The Driller. Contact bobpelikan@comcast.net to request a copy of The Pump Book, a compilation of Bob's columns for reference or training available for only $20.

Recommended Content

JOIN TODAY
to unlock your recommendations.

Already have an account? Sign In

  • geotechnical drilling rig

    6 Onsite Phrases Environmental Drillers Hate

    Here are six phrases that highlight common frustrations...
    Markets
    By: Jeff Garby
  • Wayne Nash

    Pipe Stuck? Common Causes and Solutions for Drillers

    If you have drilled for any length of time, sooner or...
    Opinions
    By: Wayne Nash
  • submersible pumps, water well pumps

    Selecting and Sizing Submersible Pump Cable

    This article helps pump installers and servicers decide...
    Opinions
    By: Bob Pelikan
You must login or register in order to post a comment.

Report Abusive Comment

Subscribe For Free!
  • eNewsletters
  • Online Registration
  • Subscription Customer Service
  • Manage My Preferences

The Driller Newscast: Coiled Tubing Drilling and the Future of Geothermal

The Driller Newscast: Coiled Tubing Drilling and the Future of Geothermal

The Driller Newscast: New York Geo Talks 2025 Conference with Hands-on Driller Education

The Driller Newscast: New York Geo Talks 2025 Conference with Hands-on Driller Education

The Driller Newscast, Episode 147: Global Geothermal Collaboration at NY-GEO 2025

The Driller Newscast, Episode 147: Global Geothermal Collaboration at NY-GEO 2025

The Driller Newscast: 21st Century Drillers | Part 1 DEMAND

The Driller Newscast: 21st Century Drillers | Part 1 DEMAND

More Videos

Sponsored Content

Sponsored Content is a special paid section where industry companies provide high quality, objective, non-commercial content around topics of interest to the The Driller audience. All Sponsored Content is supplied by the advertising company and any opinions expressed in this article are those of the author and not necessarily reflect the views of The Driller or its parent company, BNP Media. Interested in participating in our Sponsored Content section? Contact your local rep!

close
  • demo of a DM450 drilling rig during a customer factory visit
    Sponsored byGeoprobe

    Built for You: Smarter Drill Rigs, Stronger Support, Bigger Opportunities

Popular Stories

MainPhotoTwoBrothers.jpg

Two Brothers' Journey Through the Drilling Industry

Tariffs

Tariffs Shake Up the Drilling Industry

AI and Drought Concerns

AI’s Growing Thirst for Water and Power

The Driller Classifieds

COMPRESSORS

EAST WEST MACHINERY & DRILLING IS BUYING AND SELLING AIR COMPRESSORS, AIR BOOSTERS, AIR ENDS & PARTS
Company: East West Machinery

DRILL RIGS

LOOKING FOR LATE MODEL TOPHEADS & DRILLTECH D25'S
Company: Spikes’s Rig Sales

DRILL RIG PARTS

MEETING DRILLERS NEEDS AROUND THE WORLD
Company: East West Machinery

ELEVATORS

SEMCO INC. PIPE ELEVATORS
Company: Semco Inc.

GROUTERS

GROUTING EQUIPMENT - GROUT PUMPS & GROUT HOSE REELS
Company: Geo-Loop Inc.

PUMP HOISTS

SEMCO INC. - BASIC PUMP HOISTS
Company: Semco Inc.

WELL PACKERS

LANSAS PRODUCTS - INFLATABLE WELL PACKERS
Company: Vanderlans Lansas Products

WELL SCREENS

WELL SCREENS & SLOTTED PIPE
Company: Alloy Screen Works

Products

Water Quality Engineering: Physical / Chemical Treatment Processes

Water Quality Engineering: Physical / Chemical Treatment Processes

By carefully explaining both the underlying theory and the underlying mathematics, this text enables readers to fully grasp the fundamentals of physical and chemical treatment processes for water and wastewater.

See More Products

Subscribe to The Driller Newscast

Related Articles

  • Phase Converters: Running a Three-phase Pump on Single-phase

    See More
  • Tech Topics: Three-phase Pump Control Panels - Part 2

    See More
  • Tech Topics: Three-phase Pump Control Panels

    See More

Related Directories

  • Solar Power & Pump Supply

    Solar Power & Pump Supply is the leading expert in the solar water pumping industry for over 20 years. We are the primary distributor of SunRotor (submersible) and Dankoff (surface) solar water pumps. We carry everything you need for installation from solar panels and racks to wire and fittings. We offer live phone support for system design, troubleshooting, and general questions. Please call us 866-246-7652 to inquire about becoming a dealer. We Make Solar Easy!
×

Dig deeper into the drilling and water supply industry!

Build your knowledge with The Driller, covering the people, equipment and technologies across drilling markets.

SIGN UP NOW
  • RESOURCES
    • Advertise
    • Contact Us
    • Directories
    • Store
    • Want More
    • Classifieds
  • SIGN UP TODAY
    • Create Account
    • eNewsletters
    • Customer Service
    • Manage Preferences
  • SERVICES
    • Marketing Services
    • Reprints
    • Market Research
    • List Rental
    • Survey/Respondent Access
  • STAY CONNECTED
    • LinkedIn
    • Facebook
    • YouTube
    • X (Twitter)
  • PRIVACY
    • PRIVACY POLICY
    • TERMS & CONDITIONS
    • DO NOT SELL MY PERSONAL INFORMATION
    • PRIVACY REQUEST
    • ACCESSIBILITY

Copyright ©2025. All Rights Reserved BNP Media.

Design, CMS, Hosting & Web Development :: ePublishing

The Driller
search
cart
facebook twitter linkedin youtube
  • Sign In
  • Create Account
  • Sign Out
  • My Account
The Driller
  • NEWS
    • Water
    • Geothermal
    • Construction
    • Environmental
    • Mining
    • All Industry News
  • CLASSIFIEDS
  • EQUIPMENT
    • Rigs & Heavy Equipment
    • Consumables
    • Pumps
    • Featured Products
  • SAFETY
  • VIDEOS
    • Newscast
    • Drill Talks
    • Ask Brock
    • Emerging Drillers
  • EDUCATION
    • Drilling Business Insights
    • Reference Desk
    • Sponsored Insights
  • SOURCEBOOK
  • EVENTS
    • Conferences & Demo Days
    • Newscast LIVE
  • SUBMIT
    • Drillers @Work
  • ABOUT
    • Contact
    • Advertise
  • SIGN UP