Maintaining a Wind-Electric System

Wind turbines work long and hard in a severe environment. “Wind turbines are machines. They have moving parts,” notes John Hippensteel owner of Lake Michigan Wind and Sun. “That means they require maintenance.”

Maintenance takes time and money.

Ignoring routine maintenance will surely reduce performance and will very likely lead to even more costly maintenance in the future — or even failure. Don’t be lured by exaggerated claims of maintenancefree operation made by wind turbine manufacturers or installers. No wind generator is “maintenance free” — unless you leave it in its box.

This section briefly discusses maintenance of wind energy systems. A more detailed account is offered in Dan’s book, Power from the Wind.This material is intended to apprise readers of a vital, though sometimes overlooked, part of living with a wind-electric system. It is not meant to discourage you from pursuing wind energy, but rather to drive home the importance of maintenance requirements and let you know what you’re getting into. You should embark on this venture with your eyes wide open. Remember: you can hire a professional to inspect and maintain your system.

What’s Required

We recommend twice-a-year inspections for all small wind systems. The first inspection should be in the spring once the weather warms, but before thunderstorm season. Thunderstorms are likely the most violent weather your turbine will encounter, and you want to be sure it’s in good shape before Nature’s onslaught. The second inspection should occur in the fall to be sure your turbine is ready for winter. The last thing you will want to do is climb a tower in a
30 mile-per-hour wind at -30° F to take care of something that you could have been fixed on a warm fall day.

Inspections should be performed on windless days. This makes climbing the tower or lowering the tower easier, safer, and more comfortable. Wind turbines on climbable towers should be shut down to prevent injury. Never perform inspection and maintenance when the blades are spinning. After you’ve climbed the tower, tie the blades to the tower so they can’t spin, just in case the winds start up while you’re working on the turbine. Also, be sure to brake a wind turbine on a tilt-up tower before lowering it.

What constitutes inspection and maintenance will vary with the particular wind turbine and type of tower. Installation manuals that come with the turbine and/or tower usually provide detailed instructions. Be sure to read them carefully. Before performing your semi-annual maintenance, call the manufacturer for any maintenance updates. It’s a good idea to check for updates every year if you have installed a relatively new turbine — one that’s been released within the last five years. For turbines that have been in the field for long periods updates are very likely going to be rare.

Before you climb a tower or lower a turbine to the ground in the case of tilt-up towers, be sure to listen for unusual sounds — for example, clunking, banging or grinding. They indicate a bad alternator or bearings. Check for vibrations. Unusual sounds from a wind turbine should be noted any time it is operating.

You should also test the electrical production of the turbine. Detailed instructions on how to do this should be in the installation manual. Contact the manufacturer if you have any questions on test procedures. Be sure to talk to engineers, not sales personnel. Any unusual sound or low output should be taken as an indication that a detailed inspection is necessary.

Inspecting a wind system requires a careful examination of the turbine, including the blades, tail, tail boom and internal components; the tower; and guy cables, if any, and connections to anchors. You’ll also need to inspect the electrical wires and connections. Loose nuts in the tower and turbine will need to be tightened according to the manufacturer’s recommendations. Cracked nuts and bolts must be replaced.

You also need to check for rust, cracked welds, and cracks in the tower and the turbine. Cracks or rust must be attended to immediately. Cracked welds indicate that something is seriously wrong. Lower the tower and fix them ASAP.

Be sure to examine the furling mechanism, including the cable that is used to manually furl the tail, if present. When you have reached the base, be sure the furling winch, if any, is in good shape and operating correctly. Also, check the connections on ground rods. Be sure that all contact surfaces are clean and free of oxidation. Inspect other electrical components such as surge arrestors for damage and replace them, if necessary. If your system is equipped with a dynamic brake (the mechanism that shorts the alternator to stop the turbine), be sure to check the switch.

If overspeed protection is provided by a vertical furling mechanism or a blade pitch mechanism, be sure to inspect the bolts, pins and springs for damage. Tighten loose bolts per manufacturers’ recommendations and grease as needed.

When climbing a tower, be sure to wear a safety harness (preferably a full-body harness). When climbing a tower or working on a platform, be sure you are securely tied in or clipped in at all times. Secure all tools and extra parts so they don’t fall and injure people or pets below you.

Be sure to read the entire inspection and maintenance protocol before ascending the tower to be certain you have all the tools and parts you need. Make a checklist of tools and inspection and maintenance duties on the front and back of a note card. Carry it with you to the top of the tower. You might want to put a duplicate copy in your pocket in case a breeze comes and sends your list on a cross-country flight.

If your turbine is mounted on a tilt-up tower, you will need to lower it to inspect the turbine. You’ll need to inspect the guy cables, their attachment to the anchors, the tower, and electrical wire that carries electricity from the tower to the balance of system.

Routine inspection and maintenance of a wind turbine and tower is an insurance policy. Like taking your car in for oil changes and other scheduled maintenance, it ensures longer life and can save a lot of money over the long haul. Tightening a loose nut is a lot cheaper than replacing a part, or worse, an entire wind turbine that’s been damaged when a nut comes off. Proper maintenance can help the system last for 20 to 30 years — helping you get the most for
your investment.

If you install a battery bank, you’ll need to inspect and maintain the batteries as well. Off-grid battery banks typically require a lot more care than batteries installed in grid-connected systems. In contrast, inverters are generally fairly maintenance free. The only attention they require is when they break down, which is rare.

If you’re not up to the task or can never seem to get around to chores, you may want to hire a professional to inspect your turbine, tower and other components every year. If that’s not an option, you may want to think about a less maintenance-intensive renewable energy system, like a PV system.