Troubleshooting: Low Power Output
We usually do not see a problem with the controller result in low power output. A bad controller normally would result in no power output; however, occasionally a short in one diode or faulty circuit board can result in low power output. Low power output normally is either an installation/system issue, a low wind resource, or an issue in the turbine.
First make sure that the turbine appears to spin freely and smoothly. If so, then disconnect the three leads from the controller and brake switch, and perform the phase-to-phase test as described in the Electrical Tests listed in the manual. Do this on a day of low to moderate wind, and keep in mind that voltages will change based on the wind speed. If you notice one combination of wire has an especially low voltage compared with the other combinations, then there is an issue, most likely with the stator or the connection between the stator wires and brush wires in the turbine.
We recommend that you check into the following during your next routine inspection:
1. Confirm that the brushes are not broken or the brush block is not melted. Polish off any carbon build up on the slip rings and brushes with fine grit sandpaper or Emory cloth.
2. Confirm that the turbine stator wiring (wire nuts) are not damaged, melted, or that the wire nuts have not come loose. Try unscrewing the wire nuts and putting fresh wire back in.
• Detailed instructions for stator wiring: Remove 1 inch (25 mm) of wire insulation and scrape off the clear coating. Hold the wires parallel and twist them together clockwise. You should put dielectric grease inside of the wire nut before twisting it onto the wires. Twist on the wire nut tightly and securely. Coat wire nuts and terminal strip connections with dielectric grease including the area around the opening between the wire nut and wires.
3. Remove the blades or blade extension from the rotor, and make sure that the rotor spins smoothly and doesn't appear to wobble. If it wobbles, either the rotor is imbalanced or the spindle shaft is bent. This will also allow you to feel if the spindle bearings are in good shape.
Next, unbolt the rotor can from the spindle. Inspect the interior of the rotor to check the magnets. Seeing a small amount of magnetic debris on the stator indicates that the rotor magnets are most likely rubbing slightly, probably on the paper keepers of the stator. A small amount of this debris is not a cause for concern. Even a small crack in a magnet is not a problem. What you should look out for is a major fracture in a magnet or potentially a broken magnet.
4. Another place to check is the pivot area. In a Whisper 500, make sure that the return spring is still 4.5 inches, as it is possible the return spring has broken. Also check that when the turbine is sitting level and you furl it by hand, that it will unfurl by itself (a very gentle shake may be necessary). If it unfurls smoothly and not too fast, that is good. Otherwise it may be furling too easily or even getting stuck in furl for too long. You may need to adjust the Nylock nut on the pivot shaft (see #4 above on how to adjust the nut).