---------------------------------------------------------- AeroElectric-List Digest Archive --- Total Messages Posted Sun 02/10/08: 4 ---------------------------------------------------------- Today's Message Index: ---------------------- 1. 04:54 AM - Re: Know Your Charging System article () 2. 05:09 AM - Re: Know Your Charging System article () 3. 03:56 PM - Re: MOV device usage and spec (Robert L. Nuckolls, III) 4. 06:35 PM - Re: "N" Revision to 13/8 affect Z-33? (Robert L. Nuckolls, III) ________________________________ Message 1 _____________________________________ Time: 04:54:39 AM PST US From: Subject: AeroElectric-List: Re: Know Your Charging System article This ARTICLE is for Externally Regulated Alternators! Jay great article and I agree with it 100%, but it's for EXTERNALLY REGULATED AIRCRAFT ALTERNATORS ONLY. JUST A FYI. The part about no OVER LOADING applies to all alternators, but the part about SWITCH throwing is not good for all alternators. Their suggestion is to: 1) Leave the alternator switch OFF BEFORE starting the engine. 2) Turn the alternator switch ON AFTER the engine is running. This CAN AND HAS DAMAGED Internal-Voltage Regulated Alternators (I-VR). I-VR ALTERNATORS LIKE A NIPPONDENSO, which are popular with the, kit-plane, home-building, amateur/experimental community are a totally different deal. This is the problem, people try to apply old time E-VR ideas to I-VR and get in trouble. It's a whole new ball game. I-VR alternators are designed to be ON before engine start. They have a soft start function in their "brain" or IC chip controller. I-VR alternators are made to STAY ON during engine shut down. Again it knows when to knock off work. Some say it does not matter, but I have seen a correlation between I-VR failures and pilots that do the switch throwing procedure while the engine is turning. It's real simple, ALT ON with master BEFORE start, ALT OFF with master AFTER shut down. Look at an auto-repair manual for cars; you will see how the KEY operation works in regards to the alternator. Over riding the AUTO function of the IC controller inside a I-VR is not necessary or desirable. Cheers George >Subject: Know Your Charging System article >From: "jayb" >I recently ran across this article regarding aircraft >alternator operation >and charging systems. http://www.nflite.com/ChargingSystem.html >If you scroll down past the general >explanations, >there is a section titled "Don't overload the system!". >The short story is that the author recommends starting >the engine with ALT field off so as to not overload the >charging system and/or put undue strain on the diode >rectifier. Is there anything to this theory? >Regards, Jay --------------------------------- Be a better friend, newshound, and know-it-all with Yahoo! Mobile. Try it now. ________________________________ Message 2 _____________________________________ Time: 05:09:02 AM PST US From: Subject: AeroElectric-List: Re: Know Your Charging System article PS: This statment in the article is faults: >The ignition switch (in a car) is also cutting off >power to the voltage regulator (which shuts down >the alternator) while the engine is being started. That is 100% un-true. To be clear , the power to the IGN lead of I-VR alternators comes on and off with the car's IGNITION. The fact the alternator manufactures label it IGN should be a clue! (you think ha-ha) This is where people get externally regulated alternators and generator mixed up with modern internally regulate alternators, which have a controller or IC "brain" to automatically handle the alternators functions. Now I can't say for sure ALL brands work this way, but most modern (since early mid 1980's) NipponDenso alternators work this way. How other brands or knock-off clones of ND alternators work is to be determined (with some simple test and observations.) Again externally regulated and internally regulated are APPLES and ORANGES, at least when it comes to its "spool up" or powering-up and shut down. Cheers George --------------------------------- ________________________________ Message 3 _____________________________________ Time: 03:56:37 PM PST US From: "Robert L. Nuckolls, III" Subject: Re: AeroElectric-List: MOV device usage and spec At 08:18 AM 2/9/2008 -0500, you wrote: > > >This is probably directed to Bob more than anyone else, but if there are >comments, please feel free. > > >I have noticed the use of MOV's in many of the "Z" drawings. I understand >their value in protecting switches etc. Do you have specs on what MOV >should be used for different applications, such as for contactors, flap / >gear motors, or any other inductive load? They have been removed from all but the oldest, and yet to be updated drawings. The MOV's are useful devices in the large transient world (read lightning) but not practical in aircraft or other DC power systems as transient suppressors. Are there any MOV's left in the current suite of z-figures? If you spot one, let me know and I'll get it corrected asap. Thanks! Bob . . . ________________________________ Message 4 _____________________________________ Time: 06:35:50 PM PST US From: "Robert L. Nuckolls, III" Subject: Re: AeroElectric-List: "N" Revision to 13/8 affect Z-33? At 01:55 PM 2/8/2008 -0500, you wrote: > > >Bob, I have a pair of 2-year-old P-mags, and was planning to install them >per Z-33. You've been keeping up with the Emagair developments. I note >your changes to the E-mag/P-mag wiring in the latest Z-13/8 >revision. Should I go ahead and follow Z-33, or change it to run both >P-mags from the Main Power bus? Thanks. Z-33 has been removed from the latest encarnation of the Z-figures and yes, if you have dual p-mags, the need to "test" the built in alternator is an easily managed by killing the main bus during the occasional ground test. After a visit to Emagair for some enlightening conversation, the architecture and operating philosophy depicted in Z-13/8 was evolved and published. You mentioned that the devices you have are two years old. I'm not privy to the evolutionary details of their products. You'd best seek answers for any concerns you have directly with them. I'm certain that you'll find Brad or Tom very helpful. 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