Skip to main content

Generators on the farm

Are you ready for the next power outage?

As manager of member services for Boone Electric Cooperative in Columbia, Mo., Chris Rohlfing knows a lot about electricity. Yet recently, when he tried using a portable generator to power an air compressor to fill a flat tire on his combine, he found he had more to learn.

“I took my 1,500-watt generator out in the field to start up a 400-watt air compressor, thinking I had plenty of power,” said Rohlfing, who grows corn and soybeans in his spare time. “But the generator didn’t supply enough power to start up the compressor.”

The experience left him a bit, well, deflated. He learned the hard way that you often need much more power to start up an electric motor than to run it. A refrigerator, for example, may take 600


watts of power to operate on an ongoing basis, but it might require 1,200 to 1,500 watts to start up.

People tend to purchase undersized generators, Rohlfing added. He recommends that you refer to your electric device’s manual to determine its start-up power requirements. Add up the requirements for every piece of equipment that you plan to power. You can burn out your generator by using it to power devices beyond its capacity.
Why purchase a generator?

Robert Schultheis also knows a thing or two about generators. He’s a natural resource engineering specialist for University of Missouri Extension, based in Webster County. He works out of Marshfield, Mo., and served on the Multi-Agency Resource Center team that helped citizens affected by the deadly tornado in Joplin last spring. Schultheis sees a growing interest in generators to provide power during outages. As he points out, weather fronts from cold northern states and the warm South frequently collide over Today’s Farmer country, and that can mean ice storms and tornadoes and resulting power outages.

“Every time a big storm hits, there’s a mad dash to the home improvement store to buy a generator,” he said. “But when the ice storm of 2007 hit, you couldn’t find a generator—stores sold out. Lots of people couldn’t even find the right cables to hook them up.” For those concerned about having reliable electric power, he suggests you look into purchasing a generator now, before the next outage strikes.

As Rohlfing explained, “No power provider can guarantee that you’ll always have power.”
Farmers have special needs for generators. Often we depend on electric-powered wells for water for our homes and livestock watering tanks. “A typical three-quarter-horsepower well pump draws 800 watts when running, but draws up to 3,200 watts when starting,” Schultheis said. “A 4,500 to 5,500 watt portable generator would be a minimum size to run a farm home, but much depends on what you’re trying to power.”

Joseph Zulovich, an Extension agricultural engineer at the University of Missouri, adds to the list of reasons you should consider an on-farm generator. “Depending upon the situation, a one-time loss may more than cover the cost of purchasing and installing a standby generator system,” he said. “For example, if you have a mechanically-ventilated building that is housing a large number of animals, significant animal death losses can begin as quickly as 15 to 30 minutes after power failure begins.” In addition, such livestock operators might receive a reduction in insurance costs if they install a standby generator.

It’s not just farmers who are buying generators. Boone Electric Co-op serves a mostly suburban area, and residential homeowners are catching the fever. “We see increasing interest in expensive built-in stand-by generators to power all their needs if the power goes out, from computers and TVs to air conditioning and freezers,” Rohlfing said.

According to Rohlfing, Boone Electric Co-op customer-members seldom experience power outages. “But as the media reports on weather-related outages around the country, people are starting to realize how important electric energy is, and no one wants to go without,” he said. 

What type do you need?
There are basically three types of generators—portable box-types, power take-off units that run off a tractor and built-in stand-by generators. 

To determine which fits your needs, assess how you’ll use it, how much power you’ll need and your budget.
If you just want to keep the lights on, a portable gas-powered generator provides the least expensive and safest alternative. It can power things like refrigerators, microwaves and power tools. RV owners use them when camping to power air conditioners and heaters, but they’re usually not powerful enough for in-home heating and cooling. 

If you raise livestock and need a constant source of power for ventilation fans, consider a PTO unit connected to your tractor’s engine, as long as you can quickly get the tractor-driven generator operational after a power failure.

Larger confinement operations that need ventilation fans and dairies that must cool milk often depend on large, permanent stand-by generators that automatically switch on after the utility company’s power goes out for a designated length of time. These are the most expensive, but most reliable, alternatives.

Tempco Industrial Power provides an online generator buyer’s guide that suggests you ask the following questions before you buy:
•    What are your power requirements?
•    What are the start-up surge requirements of your equipment?
•    What type of fuel does the generator use?
•    For a portable generator, how long can the generator operate before it needs to be refueled? How portable is it? How heavy? Does it come with wheels or handles?
•    What else will you need, such as fuel storage units, power cords, ventilation, storage and professional installation?
Schultheis offers his own tips on what to consider. “Choosing a brand should be based on durability, reliability, ease of service, ready access to repair parts and appropriate sizing to power the critical electric loads,” he said. “Most farmers I know with generators have a 5,500- to 8,500-watt gasoline-powered portable generator for the home and/or a diesel tractor PTO-powered unit on wheels to power the larger farm loads.” 

The Tempco website, as well as one maintained by Virginia Cooperative Extension, provide charts to help you determine your wattage requirements:

How can you stay safe?

Before you select your generator, educate yourself on important safety precautions, as generators can be dangerous if used improperly.

When your power’s off for more than 12 hours, electric utilities get calls from people asking how to use portable generators. “The calls go something like this,” Rohlfing reports. “A neighbor tells the caller to put a generator in the basement with an open window, shut off the breaker and plug the generator right into the breaker. This can be very dangerous!”

First of all, he said, never use your portable generator inside—whether it’s the house, basement, shop, barn or garage, as it can cause carbon monoxide poisoning. Place the generator outside and run heavy-duty extension cords from it to devices such as refrigerators.

“In 2007, a major ice storm caused power outages in Missouri’s Bootheel,” Rohlfing said. “We had one fatality from carbon monoxide poisoning when a person left a portable gas-powered generator on all night in his garage—even though he left the garage door part-way open for ventilation.” 

Secondly, never patch your generator into your electric breaker box, even if the breaker is disconnected. Current could flow back through the unswitched neutral line as it seeks the best ground. If the ground is better at the utility’s transformer than at the service, this could cause an unsafe situation for utility workers.

The same goes for the larger built-in stand-by generators. Before installing these big boys, contact your electric power provider for installation instructions. Linemen at Boone Electric Co-op can attest to the need for a reliable grounding device. Twice now, when customers used large standby generators with just two single-phase wires connected to two-pole switches, linemen at nearby transformer sites were hit by a ball of fire. Fortunately, no one was hurt.

“As a result, we decided to require a three-pole system to assure proper grounding of larger generators,” Rohlfing said. A three-phase transfer switch can cost about $200. A third pole with a transfer switch can run $500. But the extra expense can save lives.

No matter what type of generator you choose, be sure to read all the manufacturer’s recommendations on its safe use. Contact your electric provider before installing a generator. Always place portables and PTO units outside when in use, and properly ventilate built-ins to avoid carbon monoxide poisoning. Finally, research the safe storage and use of fuel.

Kinds of Generators

Portable generator
Consider using if: You need to power up lights, a water well and a refrigerator, but not an air conditioner or furnace. Bigger loads with large motors require more juice.
Cost: From $600 for a 6,000 watt unit to $4,600 for 20,000 watts. Quieter and smaller units can be more expensive. 
Benefits: As Rohlfing said, you can haul it to Grandma’s house or wherever you need it.
Fuel: Gasoline. Schultheis reported that a typical gas-powered generator comes with a four to eight-gallon gas tank, which might last six to ten hours.
Manufacturers include: Briggs & Stratton, Honda, Lincoln Electric Robin, Troy-Bilt, Vanguard.
Safety tips: Keep generators outdoors. Gasoline exhaust can cause carbon monoxide poisoning. Don’t store gasoline in your garage—it can explode if a spark happens to fly. In addition, gas gets old. Instead of storing gas in small tanks, Schultheis suggests you keep your car’s fuel tank full and purchase a siphon to refuel the generator’s tank.  Use a heavy-duty 10- or 12-gauge extension cord to link it to equipment that needs electric power.

Permanent stand-by generator
Consider using if: You raise livestock in situations that demand fans for ventilation, or if you operate a dairy where you need to cool milk.
Cost: $5,000 to $22,000 and up, plus the cost of switches and installation.
Benefits: Provides the most reliable stand-by power source. You can wire it to automatically start up when the power goes out for a certain length of time.
Fuel: Propane, natural gas or diesel. Propane and natural gas provide a safe, reliable fuel source, even during a power outage. Diesel is less flammable than propane or natural gas, but it tends to age—you must start up the engine to burn off old fuel and replace it every few months.
Manufacturers include: Vanguard, Kohler, Ford, John Deere.
Safety tips: It requires a large, dedicated, vented space. It must be permanently mounted on concrete.  You must work with a certified electric contractor and with your power provider to assure safe installation and use.

Power take-off (PTO) unit on a tractor
Consider using if: You have a tractor with a PTO and you need a generator for basic on-farm use. 
Cost: You can purchase a 25,000-watt PTO unit with a three-point hitch and drive shaft for about $3,000. 
Benefits: You can use a trailer to haul the generator where you need it.
Fuel: Diesel from the tractor.
Manufacturers include: Baldor, North Star, Subaru, Voltmaster by Wanco.
Safety tips: Make sure safety guards are in place and take extreme care to avoid getting a sleeve caught in the revolving PTO—PTOs can cause death and dismemberment. Stabilize the PTO unit so it can’t move. Operate the PTO outdoors to avoid carbon monoxide poisoning.

  • Created on .
  • Hits: 10743