At Willow Run Stables outside Mequon, Wis., conditions quickly will deteriorate if the power fails, taking the farm's well pump down with it. At other operations, losing the ability to grind feed, run conveyors or operate ventilation fans could spell economic disaster if power is lost for an extended period of time.

The first step to setting up a backup power system is to separate the circuits to be run by the Hobart generator/welder from the main breaker box. (Progressive Farmer image: Ron Piskula)

Willow Run owners Gary and Kate Oldenburg have boarding space for nearly three dozen horses. Delivery of water to the stalls is a critical function.

With rugged winters and stormy spring weather, the Oldenburgs decided it was time to install a backup generator with enough power to run their water pump and barn lights. They chose the new Champion Elite 11,000-watt generator and welder from Hobart Welding Products. As a backup generator, the Elite is suitable to meet medium demand for electricity, such as water pumps, lights, outlets and power tools.

Generators are sized by the wattage and voltage they produce. There are man-portable generators that produce as few as 1,000 watts of power to generators 100 times larger or more—big enough to operate large livestock operations.

Choosing a capable machine begins with calculating the power needed to keep critical circuits operating during a power interruption, says Joe Sinkula, agricultural consultant with Wisconsin Public Service Corp. "Make sure you pick the right size to run the load," he says.

The power required to run a piece of machinery is calculated in watts. Watts equals volts times amps. By adding up the watts to run each piece of equipment, you determine the minimum supply of power you will need to keep your critical circuits functioning.

Remember that starting a motor requires three to seven times the current needed by the motor when it is operating normally. But not all the motors need to start at once, so consider the starting current of your largest motor. Add that requirement to the operating current needed to power the remainder of your critical electrical circuits to determine total demand for backup power.

You also may want to consider the electricity needed to power "nice-to-runs," or those functions that would be useful to have in operation—an additional bank of outlets or lights—but not critical to the farm's ongoing functions.

Overloading a generator because of poor planning can result in deficient power quality and can damage the generator and your equipment. On the other hand, it is not a good idea to purchase a generator with an electrical capacity well beyond your power needs, Sinkula says. If your generator is under only a partial load, the engine may not reach full operating temperature. That can damage the engine.

A backup generator, whether portable or permanently installed, requires a double throw, or isolation, switch. The switch serves several functions.

It is installed for reasons of safety. Connecting a generator directly into any point of electrical wiring without a transfer switch is illegal and dangerous because it may cause backfeeding.

Backfeeding is the result of sending electricity from your backup system out onto utility power lines. It energizes the transformer serving your farm and could cause the death of anyone working to restore power to your home and farm. That's because electrical transformers work the same in either direction.

The transformer reduces the primary voltage of several thousand volts on an electrical line to the 240-volt service delivered to your operation. Putting power onto the line from your backup generator through the transformer energizes the line to the primary voltage.

The switch also is installed to isolate a handful of critical electrical circuits from the incoming electrical service. If the generator is powering those circuits and regular power is restored, that electricity will not flow to those isolated circuits until the generator is shut down and the transfer switch is set to receive commercial electrical service.

Finally, the switch prevents power from your generator and the power company from energizing your electrical system at the same time, which risks the catastrophic failure of your generator and equipment.

Installation of the switch and wiring of the critical circuits is a job for a qualified electrician. This is not a job for taking shortcuts.

(AG)

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