Wind-Electric System Maintenance

If it’s human-made and has moving parts, it needs maintenance. It doesn’t matter if it’s a spinning engine, a spinning wheel, or a spinning wind generator. You can’t run a car for years—or even months—without maintenance and expect it to last long. And it’s no different with a wind generator.

Veteran wind energy expert Mick Sagrillo says that the “average home-sized wind turbine will put on as many ‘miles’ in four months as the average car does in 100,000 miles.” And regular maintenance is crucial for the survival, safety, and energy production of a wind-electric system. Once a year is a minimum for inspection and maintenance, and twice a year is usually better, especially if you have a good wind resource or experience frequent high winds or turbulence. Although some wind generator manufacturers say you can do a turbine and tower inspection with binoculars, we strongly recommend a more up-close approach: a hands-on, bottom-to-top, comprehensive annual inspection.

Most modern wind generators do not have parts that need to be routinely replaced, like the brushes or bearings of older machines. So routine maintenance is primarily focused on inspection of the whole machine, cleaning, and tightening hardware. The spinning turbine and wind forces acting on a tower can cause vibration, which can loosen or damage hard­ware, turnbuckles, and other tower and turbine components. These are the types of things to watch for during an inspection.

Get ready first (see “Maintenance Gear” sidebar), and prepare all the climbing gear, tools, supplies, and spare parts you may need for the job. Use a good checklist and a digital camera to record any problems found. And have all the equipment manuals available—you’ll be amazed at what you learn by reading them!

On the Ground: Electrical & Electronics

Before you climb the tower, there’s a lot of work to be done on the ground. In addition to inspecting the tower (see below), we like to do maintenance and troubleshooting in the power room before we climb. Finding problems on the ground prior to climbing will help us know what to look for aloft.

Turbine to Inverter/Controller Wire Run

• Look for signs of damage on all conduit, wire runs, junction boxes, and conduit fittings, such as water intrusion, condensation, chew marks from critters, cracks, frost-heaving, and so on. Long conduit runs that were improperly installed can store several gallons of water, so be aware when opening junction boxes.
• Check wire terminals on all components (disconnects, junction boxes, inverter, controller) for proper tightness and signs of arcing or other degradation.
• Test all fuses and circuit breakers for electrical deterior­ation using the continuity tester on a multimeter and look for physical deterioration. Cartridge fuses can deteriorate over time, especially in outdoor installations.
• Use a multimeter to check all surge arrestors. SOV- and MOV-type arrestors can only take so many voltage spikes before failing.
• Use a megohmmeter on wire runs to check for ground faults. Skinned or cracked wire insulation in underground conduit is one of the most common causes of ground faults. At the very least, system performance will suffer. Some older inverters can be damaged by ground faults. Worse yet, if the equipment grounding system is compromised as well, a shock hazard can result.
• While the turbine is operating, check for balanced three-phase output (when applicable). Allow for the fact that there will be variations in the wind speed and thus the voltage while you are moving the meter probes—you’re looking for variations of 10% or more between phases. Test two or three times to rule out variations caused by changing wind speed.
• Perform other turbine-specific electrical tests per the manufacturer’s recommendations. A good owner’s manual will include testing protocols for the turbine electronics.