Switch to Three-Phase Electricity, if
Available
As farms become larger and more mechanized,
the need for larger electric motors also
increases. Three-phase electrical power needs
to be considered on all farms, especially if you
are planning for any renovations or expansions.
Do you have three-phase electrical power available at your
farm? If so, are you taking advantage of all its benefits? If you
don’t have three-phase power available, have you checked
with your local utility company recently to inquire about the
requirements to get it for your farm? As farms become larger
and more mechanized, the need for larger electric motors also
increases. Three-phase electrical power needs to be considered
on all farms, especially if you are planning for any renovations
or expansions.
Benefits of Three-Phase Power Motors
• Cause little or no voltage flicker from motor starting
• Cost considerably less (20 to 50 percent less) than
comparable single-phase motors
• Have longer useful lives than single-phase motors
• Available in a much larger range of horsepower sizes
Disadvantages of Three-Phase Power
• Not necessarily more efficient than single-phase motors
• Commercial rates (rather than residential rates) may be
charged for your electricity usage and demand charges
may be assessed (three-phase power may cost more than
single-phase power, depending on your local utility
company and also your electricity generation supplier)
How Can You Get Three-Phase Power?
You must check with your local utility company to inquire
where the nearest three-phase service is available and get a
cost estimate for providing the service to your farm. Also find
out whether you will be charged residential or commercial
rates for the electricity used on the farm. In most cases, you
will be charged a commercial rate, but don’t let that
discourage you. In this era of deregulated electricity, you may
find that the benefits of three-phase power offset the higher
cost per kilowatt-hour for the electricity.
Be prepared to negotiate with your local utility company on
the issue of three-phase power. For example, one farmer
needed three-phase power because he was purchasing a
grain-drying system with a 30-horsepower fan for each bin.
The utility company would provide the three-phase power at
no up-front charge, but then the farmer would be charged a
commercial rate for his electricity use. The farmer negotiated
that he would pay $3,500 to have the three-phase power
installed and then continue to pay residential rates.
Even if you get three-phase power, you can continue to
operate your present single-phase motors on one leg of
three-phase power, but then you are obviously not reaping all
the benefits of three-phase power. In the event that you cannot
get three-phase power, three-phase motors can be operated on
single-phase power, but a phase converter must be used. Phase
converters are costly and can be expensive to operate.
Farmers must establish energy strategies to cope with
escalating prices for energy. Decisions regarding single- or
three-phase power represent one of the many components in
developing, implementing, and updating an energy strategy.
Contact Information
Daniel Ciolkosz, P.E.
Assistant Professor and Research Associate
dec109@psu.edu
814-863-3484
Penn State College of Agricultural Sciences research and extension programs
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