---------------------------------------------------------- AeroElectric-List Digest Archive --- Total Messages Posted Sat 10/07/17: 6 ---------------------------------------------------------- Today's Message Index: ---------------------- 1. 10:09 AM - Re: home wiring ground faults (GLEN MATEJCEK) 2. 11:42 AM - Re: alternator whine (Alec Myers) 3. 12:34 PM - Re: IR Alternator Voltage (eschlanser) 4. 04:34 PM - Re: alternator whine (Robert L. Nuckolls, III) 5. 04:47 PM - Re: Re: IR Alternator Voltage (Robert L. Nuckolls, III) 6. 04:50 PM - Re: alternator whine (Alec Myers) ________________________________ Message 1 _____________________________________ Time: 10:09:13 AM PST US From: GLEN MATEJCEK Subject: AeroElectric-List: Re: home wiring ground faults I've seen two pertinent miswirings. One is having the ground and neutral connected together in a sub panel. The other was putting one gfci downstream of another. Both caused nuisance trips. The first scenario is actually not uncommon with hot tubs. All is well until the light is turned on, and then the gfci trips. The second was a unique situation, and didn't manifest issues until years after the installation. Ymmv, few, yada yada... ________________________________ Message 2 _____________________________________ Time: 11:42:04 AM PST US From: Alec Myers Subject: Re: AeroElectric-List: alternator whine I did a little investigation yesterday - No aircraft control affects the volume, except the volume control directly on my headset. Even turning up the panel intercom volume doesn=99t make any difference. > On Oct 6, 2017, at 10:30 AM, Robert L. Nuckolls, III wrote: > > At 08:37 PM 10/5/2017, you wrote: >> >> Hi Bob and others, >> >> My 182 has a noticeable alternator whine, about 5kHz (I=C3=A2=C2=C2=99 m guessing) at cruise rpm. I think it=C3=A2=C2=C2=99s worse recently than it used to be. >> >> Where and what should I start investigating? > > Does operation of any audio panel selector > switch or setting of any radio or audio > system volume control have an effect on > the perceived noise? > > > Bob . . . > ________________________________ Message 3 _____________________________________ Time: 12:34:55 PM PST US Subject: AeroElectric-List: Re: IR Alternator Voltage From: "eschlanser" > Sorry, I don't have the model specifics with me (can get later) but off > the top are there ways to adjust the output of IR type alternators or is > that a factory setting that cannot be changed? Is this an "it depends" > item? > > > Probably not. I've never seen an adjustable regulator on > an internally regulated machine. In fact, most external > regulators were not adjustable either. > Before you take a wrench to the airplane, check the > alternator output voltage at the alternator's b-terminal. > The internal regulator senses b-terminal voltage and > there MAY be a difference. You can probably buy a > replacement regulator but depending on the alternator, > it might be lest hassle/expense to trade it in. > > > Bob . . . [/quote] I'm having the same need as the OP. That is, low displayed voltage from my IR alternator. I understand the directions but do not know how to implement them on a running airplane. This may be an electric 101 question. How do I physically check the alternator output voltage at the alternator's b-terminal? I don't have anyone willing to reach in and hold the voltmeter test leads on a running airplane. Eric Read this topic online here: http://forums.matronics.com/viewtopic.php?p=473408#473408 ________________________________ Message 4 _____________________________________ Time: 04:34:44 PM PST US From: "Robert L. Nuckolls, III" Subject: Re: AeroElectric-List: alternator whine At 01:40 PM 10/7/2017, you wrote: >I did a little investigation yesterday - >No aircraft control affects the volume, except >the volume control directly on my headset. Even >turning up the panel intercom volume doesn=99t make any difference. Aha! Good data. check to see if your headset jacks are grounded to airframe locally. Depending on age of your Cessna, that could have been standard practice at the factory. If grounded locally, mount the jack on an insulating washer and run a ground wire all the way back to the radio grounds. You may find that there already is a ground wire but no washer . . . in which case adding the washer is likely to fix it. Bob . . . ________________________________ Message 5 _____________________________________ Time: 04:47:23 PM PST US From: "Robert L. Nuckolls, III" Subject: Re: AeroElectric-List: Re: IR Alternator Voltage > > >I'm having the same need as the OP. That is, low displayed voltage >from my IR alternator. I understand the directions but do not know >how to implement them on a running airplane. This may be an electric >101 question. How do I physically check the alternator output >voltage at the alternator's b-terminal? I don't have anyone willing >to reach in and hold the voltmeter test leads on a running airplane. > > >Eric Easy, don't PROBE the points of interest, CLIP them. I very seldom use 'probes' for any measurement, virtually all signals of interest need to be sampled while your hands are fully occupied with other tasks. Emacs! I have several dozen clip leads sets in the various tool boxes and workbenches. As a general rule, I make them up with a minimum 36" long. I have a couple of sets that are 10' long. I once built a special clip set about 40' long to watch a voltage in the 'hell hole' of a Beechjet whilst I was fiddling with knobs in the cockpit. Built yourself a 10' pair. Clip to points of interest under the cowl then sit in the cockpit taking voltage readings ar various rpm and loads. Tape the leads to under side of cowl to keep prop wash from shaking the wires so bad that it pulls the clips off . . . been there, done that. Bob . . . ________________________________ Message 6 _____________________________________ Time: 04:50:01 PM PST US From: Alec Myers Subject: Re: AeroElectric-List: alternator whine Awesome. I=99ll give it a try, and report back. On Oct 7, 2017, at 19:33, Robert L. Nuckolls, III wrote: At 01:40 PM 10/7/2017, you wrote: > I did a little investigation yesterday - > No aircraft control affects the volume, except the volume control directly on my headset. Even turning up the panel intercom volume doesn=99t ma ke any difference. Aha! Good data. check to see if your headset jacks are grounded to airframe locally. Depending on age of your Cessna, that could have been standard practice at the factory. If grounded locally, mount the jack on an insulating washer and run a ground wire all the way back to the radio grounds. You may find that there already is a ground wire but no washer . . . in which case adding the washer is likely to fix it. Bob . . . ------------------------------------------------------------------------------------- Other Matronics Email List Services ------------------------------------------------------------------------------------- Post A New Message aeroelectric-list@matronics.com UN/SUBSCRIBE http://www.matronics.com/subscription List FAQ http://www.matronics.com/FAQ/AeroElectric-List.htm Web Forum Interface To Lists http://forums.matronics.com Matronics List Wiki http://wiki.matronics.com Full Archive Search Engine http://www.matronics.com/search 7-Day List Browse http://www.matronics.com/browse/aeroelectric-list Browse Digests http://www.matronics.com/digest/aeroelectric-list Browse Other Lists http://www.matronics.com/browse Live Online Chat! http://www.matronics.com/chat Archive Downloading http://www.matronics.com/archives Photo Share http://www.matronics.com/photoshare Other Email Lists http://www.matronics.com/emaillists Contributions http://www.matronics.com/contribution ------------------------------------------------------------------------------------- These Email List Services are sponsored solely by Matronics and through the generous Contributions of its members.