---------------------------------------------------------- AeroElectric-List Digest Archive --- Total Messages Posted Wed 07/29/20: 2 ---------------------------------------------------------- Today's Message Index: ---------------------- 1. 06:54 AM - Re: Z11 field supply circuit protection (user9253) 2. 01:41 PM - Re: Re: Z11 field supply circuit protection (Robert L. Nuckolls, III) ________________________________ Message 1 _____________________________________ Time: 06:54:34 AM PST US Subject: AeroElectric-List: Re: Z11 field supply circuit protection From: "user9253" An alternator rated output is a nominal value, not an exact value. As the load is increased, the alternator will increase its output to supply the demand. If the load demands more than the alternator's rated output, the alternator might still supply the current, but the voltage will start to sag as the load gets larger. When the alternator voltage sags down to battery voltage, then the battery will also supply current to the load. Modern avionics and LED lights do not draw much current. My RV-12 needs less than 10 amps. Of course heated pitot tubes and electric seats use more. -------- Joe Gores Read this topic online here: http://forums.matronics.com/viewtopic.php?p=497474#497474 ________________________________ Message 2 _____________________________________ Time: 01:41:57 PM PST US From: "Robert L. Nuckolls, III" Subject: Re: AeroElectric-List: Re: Z11 field supply circuit protection At 09:36 PM 7/28/2020, you wrote: > >Thank you, very informative answer. I erroneously assumed that a >breaker or fuse protected the whole circuit, not just what's >downstream from it. Rookie mistake. > >About the field supply current: It makes sense that if the field >current draw is accounted for by the alternator's advertised >output, then you wouldn't include it in your energy management >calculations. Consider the internally regulated alternator wherein field current is supplied INTERNALLY. The nameplate rating would be that current available at the b-terminal irrespective of that which is consumed internally. So bringing the field lead out to accommodate an external regulator doesn't change the overall energy picture. >Question is, how do you know if a particular alternator >accounts for it? Is this standard alternator marketing practice? > Do B&C alternators account for it? Will I get 40A out of a 40 >or will I get 40A minus field current? Standard practice. You're guaranteed the nameplate rating under worst case operations (lowest rpm for full output combined with max rated internal temperatures). 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.