Pivot performance benefits from proper maintenance

Applying water with a center pivot irrigation sprinkler boosts crop efficiency and keeping it as a top performing farm asset requires regular maintenance.

Ed Heim, sales manager at Hoxie Implement Co., Inc., Hoxie, Kansas, has been a Reinke irrigation systems dealer for many years and he has seen 40-year-old pivots remain in efficient operating condition because they have been well maintained. Heim has also seen systems that are less than half that age that have not been well maintained and as a result serious problems occur, which hurts the producers’ bottom line.

Four core areas he stresses—structural, drive train, electrical and sprinkler package—are important starting points.

Structural

Starting at the pivot center, technicians often find broken chains or bolts that anchor the system to the cement pad. Not repairing these items sometimes results in structural damage as the pivot tips up and moves off the pad, Heim said. Damage to the pivot center can also occur if it is not greased regularly resulting in the pivot center twisting itself up.

Because irrigators experience high winds in western Kansas, the pipeline and trussing should be inspected each season looking for damage that includes sagging or leaning spans as the result of missing bolts or bent components. An operator should also look for structural components that are rusting out on older systems.

Rubber boots at the flex joint of each tower do get weathered with time and need to be inspected to see if they need replaced. This inspection is important as replacing a boot requires unhooking a span with a boom truck—not a handy thing to do during the season in a muddy cornfield.

Drive train

Service to the drive train is much easier to do before planting a crop. Tires need to be checked for proper air pressure and also for weathering.

“You would be surprised to find out how many people don’t check their tires,” Heim said.

This is much easier to do in the winter or spring but his technicians often see tires two-thirds flat in the early part of the growing season, he said.

Wheel gearboxes and center drives need to be inspected for leaks, have any water drained out and have the lubricant topped off during preseason maintenance. Ideally, the gear lube should be changed every three years for best protection. There are pivots that are over 20 years old that have never had the lubricant changed, he said, and that is a recipe for disaster.

U-joints and the couplers on the drivelines also need to be inspected closely because they weather and wear out and often need replaced to eliminate down time, Heim said.

Electrical

Electrical components are often the most overlooked items on an irrigation system, Heim said. All towers on an electric drive system have switches and contactors that can fail. This can occasionally be attributed to lightning but most often they fail because of normal wear and tear. Every time a tower moves, a switch needs to make a connection to give power to a contactor that needs to make a connection to get power down to the motor. The contact points wear out over time.

Many systems that are 30 years old still have the original switches and contactors except those that have had to be replaced because they failed.

“If a person would install new switches and contactors about every 10 years it would not cost very much and he would have a lot fewer electrical problems.”

Other electrical items needing inspection include all cords and wiring at the well, the control panel, the pivot and towers. Raccoons and other critters sometimes chew on these and contribute to problems during the season. Operators need to check the wires that go into the control panel and the ones coming out of the ground. Cattle can sometimes rub against the wires or conduit breaking them and that can lead to an infestation of mice or other rodents.

Electrical safety starts with proper ground rods and wires at the control panel and the pivot, he said. Technicians often find ground rods not present or ground wires not hooked up. A person cannot normally see, hear or smell electricity so proper wiring and grounding is important for safe system operation.

Sprinkler package

Maintenance of the sprinkler package components is more important than many operators realize. “In our area we do have water restrictions and water conservation efforts, so getting the water you do pump evenly distributed onto the field is very important, Heim said.

Besides checking for missing or broken sprinkler heads, growers who use drop hoses that put sprinkler heads near the ground need to inspect them for stiffness or brittleness.

“Those hoses don’t last forever,” he said. Operators should consider replacing a set rather than individual hoses before the season starts. “It is tempting to only replace the few hoses broke off during the winter, but many times other hoses are damaged. This can result in leaks and other hoses coming off during the irrigation season, which can affect water application and yields.”

Often overlooked is pressure regulators near the sprinkler heads. These regulators are installed on systems to keep a uniform amount of water coming out of each nozzle as elevation changes in the field, he said. Pressure regulators normally will last eight to 10 years in clean water before they no longer properly work. Not replacing them in the right time frame can affect the uniformity of the water application in a field resulting in reduced yields or wasted water.

Another inspection point is to watch for leaks before and during the irrigation season. Holes rusted in fittings or pipelines, drains at towers that dribble all season long and leaking gaskets on the system all contribute to inefficient water use. Growers should try to repair as many of these items as possible before the season starts.

Maintenance, he said, is much easier to perform before spring crops are planted. Corn planting traditionally begins in the last half of April and continues into May so a grower should do their best to get systems checked over by April 15. Irrigators may need to move their schedule earlier if they plan to apply chemical applications before planting corn.

The irrigator may do some service work while the crop is small but a producer may face some yield loss depending on the extent of repairs that need to be done because it is never good to be driving over a crop.

A center pivot system stays out in the elements year-round, which means the irrigator needs to stay on top of maintenance, he said. Producers should also to remember to check generator bearings, gearhead lubricant, electric motor lubricants and other well components to make sure they are in good working condition before the season.

Dave Bergmeier can be reached at 620-227-1822 or [email protected].