Re: [RE-wrenches] Bergey XL.1 HummmBuzzz

[Roy Butler]

Matt, What you are hearing is alternator noise. It's caused by the vibration from the permanent magnets passing by the alternator coils. All turbines produce some alternator sound, some more than others and the tower itself can act as a resonator, amplifying the sound. The reason you don't hear it when the turbine is unloaded is because no current is being induced in the alternator coils, so there's no resistance pushing against the rotor magnets. Unfortunately, there's nothing much to be done about it. Roy Butler Four Winds Renewable Energy, LLC 8902 Route 46, Arkport, NY 14807 607-324-9747 www.four-winds-energy.com Although no trees were killed in the sending of this message, a large number of electrons were terribly inconvenienced. On 9/30/2019 9:44 AM, Matt Sherald wrote: Friends, I've exhausted the Bergey tech support expertise on this issue and I'm hoping someone on the list may have a solution to share. I have a customer with an older XL.1 on a tilt-up tower.  The machine has been in place since 2007.  I've done some work to it over the years including blades, yaw bearings, painting, slip rings, brushes, rectifier. The machine/property has a new owner who finds the noise of the machine to be objectionable.  The original owner also noted the noise, but was not as dogged about resolving it. The noise is best described as a "hummbuzzz" and it happens when the machine rpms have slackened and then begin to accelerate again.  The transition causes some kind of electrical harmonic that is not noticeable once the rpms increase.  So, if the machine furls out of a high wind and the rpms drop then the noise begins as soon as it un-furls and the blades begin to accelerate.  The noise disappears as it comes up to speed. This noise does not happen if the machine is allowed to run unloaded (with the breaker in the off position). Anyway, I'd sure appreciate any thoughts.  Many thanks in advance! -- Matt Sherald PIMBY Energy, LLC NABCEP Certified Solar PV Installer® 304-704-5943 www.getpimby.blogspot.com www.getpimby.com _______________________________________________ List sponsored by Redwood Alliance List Address: RE-wrenches@lists.re-wrenches.org Change listserver email address & settings: http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org List-Archive: http://www.mail-archive.com/re-wrenches@lists.re-wrenches.org/maillist.html List rules & etiquette: www.re-wrenches.org/etiquette.htm Check out or update participant bios: www.members.re-wrenches.org

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