---------------------------------------------------------- AeroElectric-List Digest Archive --- Total Messages Posted Tue 08/19/08: 11 ---------------------------------------------------------- Today's Message Index: ---------------------- 1. 12:54 AM - Re: B&C alterator problem (Robert L. Nuckolls, III) () 2. 05:26 AM - LED Landing lights (Paul McAllister) 3. 09:02 AM - LED Landing lights (James H Nelson) 4. 09:11 AM - High resistance pops breaker? (user9253) 5. 10:00 AM - Re: High resistance pops breaker? (Dale Rogers) 6. 10:10 AM - Vertical Power VP-50 with an Egg 3.6L engine and Z19RB (DeWitt Whittington) 7. 01:26 PM - Re: Search for Gremlins (F. Tim Yoder) 8. 06:11 PM - Re: Search for Gremlins (Robert L. Nuckolls, III) 9. 06:17 PM - Re: Vertical Power VP-50 with an Egg 3.6L engine and Z19RB (Robert L. Nuckolls, III) 10. 06:48 PM - Re: High resistance pops breaker? (Robert L. Nuckolls, III) 11. 06:48 PM - Re: Re: B&C alterator problem (Robert L. Nuckolls, III) (Robert L. Nuckolls, III) ________________________________ Message 1 _____________________________________ Time: 12:54:19 AM PST US From: Subject: AeroElectric-List: Re: B&C alterator problem (Robert L. Nuckolls, III) > Bob and others - > >I have a newly purchased RV8 with a B&C 40 amp alternator and automotive > >style blade fuses. Good grounding with a firewall mounted ground bus > >which is then routed to the engine. The digital ammeter indicates a > >running load of 6-7 amps. The battery is a Concorde dry cell mounted on > >the firewall. On two separate occasions the 15 amp alternator field fuse > >has blown without any additional or noted transient loads being placed on > >the alternator. The builder had this happen to him also and he thought it > >was the battery so he replaced it. The new, year old Concorde battery has > >great cranking power so I am not looking at this as a potential > >problem. The only other problem I have noted is when using all of the > >lights, strobes, fuel pump and electric flaps the main 40 amp C/B popped > >once. Ignoring this as an overload my real problem appears to be the > >field fuse. Why does the 15 amp field fuse blow and what's the smartest > >way to diagnose this problem? Thank you. JBB The first problem is that the original builder did not understand the physics of the system he/she was crafting and chose not to study and understand why the z-figures were designed the way they are. A 40A breaker on a 40A alternator is UNDERSIZED. The nameplate rating of an alternator is for worst-case conditions. I.e. minimum rpm for full output and max ambient operating temperature. Under less stressful conditions, the alternator may deliver 15 to 25% more current. This says that the 60A breaker on the b-lead of 60A alternators in 100,000 GA aircraft is DESIGNED to nuisance trip. Suggest you replace the 40A breaker with a 30-50A current limiter out on the firewall. There should not be a field fuse with an LR series regulator. These us crowbar OV protection and are designed to work downstream of a breaker only. Is the recommended 5A breaker also installed? IF so, the wiring between the breaker and the bus needs little if any protection. The z-figures recommend a fusible link . . . exceedingly robust compared to the fuse. Now we need to figure out what's irritating the OV protection system. Do I presume correctly that the regulator also came from B&C (LR3 series?) or is there some other combination of regulator/ov in place? I'll assume that since the field protection is being nuisance tripped, there is some form of crowbar ov protection in place. The ov protection may be an older version that was sensitive to some forms of normal bus transients. The designs at both B&C and AeroElectric Connection were modified to eliminate that condition . . . the system you're working with may need to be updated. This is not a condition unique to 'crowbar' ov protection. EVERY ov protection system has some form of comparator between bus voltage and some stable reference. When a setpoint is exceeded, it sends a signal to some form of disconnect device (relay, transistor, scr, etc). There is a dynamic component to ov protection too . . . voltage excursions above the setpoint are allowed as long as they do not exceed certain time intervals. It's the fine tuning of the dynamic sensitivity that makes some products prone to nuisance trips. I've probably designed two dozen or more OV protection systems in my career, I've only had to re-tune two of them. In one case, the transient condition generated by the aircraft was greater than the Mil-STD-704 guidelines to which the product was crafted. Tell us what regulator/ov combination is installed. If an LR3, what's the manufacturing date? If an AEC crowbar module, what colors of wires does it have. Older versions are red/black, newer are orange/black. Bob . . . Bob - Thank you for opening up the design issues I hadn't even considered. I will return home next week and provide the more detailed information you request. It is a B&C voltage protection device of some sort I have seen and he used a "Z" design but I'll have to get you the specifics. Thank you. JBB ________________________________ Message 2 _____________________________________ Time: 05:26:54 AM PST US From: Paul McAllister Subject: AeroElectric-List: LED Landing lights Hi all, I am returning to the list after a multi year hiatus. I completed my Europa 914 in 2004 using many of the design principals from Bob's book. Anyhow what has prompted my return is my curiosity about the many LED landing lights and strobe light replacements I saw at the Oshkosh air show this year. The Europa doesn't lend its self well for the placement of landing lights, but I was thinking that I could craft something up myself that would work. Which brings me to my question. Does anyone on the list know what LED devices and reflectors are being used for LED landing lights. If so, I would appreciate it if someone could let me know. Thanks, Paul McAllister Europa N378PJ ________________________________ Message 3 _____________________________________ Time: 09:02:23 AM PST US Subject: AeroElectric-List: LED Landing lights From: James H Nelson Paul, Do you have the Mono-wheel? If so, use the speed fairing around the outrigger to mount the landing light. Bob Berube at Flight Crafters did a landing light in teh leading edge of the wing. I don't know who well it worked but the LED version should run cooler and thus not effect the foam in a foam wing. Other wise, cut an opening in the leading edge and and access opening in the back of it. That will work. Jim Nelson ____________________________________________________________ Can't pay your bills? Click here to learn about filing for bankruptcy. http://thirdpartyoffers.juno.com/TGL2141/fc/Ioyw6i3nfvZVjJ2OnTgLvUUGBTXGGzXcopY5DUkATuGftUJRA8DPaJ/ ________________________________ Message 4 _____________________________________ Time: 09:11:30 AM PST US Subject: AeroElectric-List: High resistance pops breaker? From: "user9253" There was a "TECHNICAL COUNSELOR" article written in the April 2008 issue of Sport Aviation about the landing light tripping a circuit breaker due to high resistance connections. You can read the complete article here: http://www.eaa.org/sportaviation/2008/april/0804_tc.pdf In the August 2008 issue, a letter to the editor questions why a higher resistance would result in higher current. Following is the "TECHNICAL COUNSELOR" author's reply in the Aug 2008 Sport Aviation: George's Reply: Using Ohm's and Watt's laws, if a connection resistance increases, the voltage drop across that resistance increases, which increases the current draw and power demands on the circuit. The power draw of the engine and the lamp increase as voltage drops. Adding to this issue is the fact that an engine-operated landing light is marginal at best in terms of the circuit breaker rating; that is, with the motor drive and the lamp, you're already close to the trip set point. As the resistance increases in the contact stacksin this case because of corrosion ... the voltage drops across each of these series connections and in turn causes the motor to see less voltage and draw more current to reach its power, which in turn would trip the breaker in concert with the light turning on, using voltage from the same source. Since the watts for the motor and lamp remain relatively constant, the current rises. As such, when you add in the voltage drop across even minor resistances in a stack of contacts, due to the voltage drop, the current draw over the entire circuit increases to the point where the circuit breaker trips.George Wilhelmsen George Wilhelmsen holds a commercial certificate with an instrument rating and has more than 1,000 hours of flight experience. He has a bachelors degree in engineering technology with a background in DC, analog, and digital controls. He flies a Beech Debonair. End of quotes. Now this is Joe writing. The landing light in question had an electric motor to retract the light into the wing when not in use. Motors do draw more current when operated at less than design voltage. Perhaps the author understands ohm's law but just did not explain it very well. I got the impression that he was saying that a lamp uses more current if the electrical connections have higher resistance. That is not true. I wonder, could this possibly be the same George? -------- Joe Gores Read this topic online here: http://forums.matronics.com/viewtopic.php?p=199509#199509 ________________________________ Message 5 _____________________________________ Time: 10:00:09 AM PST US From: Dale Rogers Subject: Re: AeroElectric-List: High resistance pops breaker? user9253 wrote: > > There was a "TECHNICAL COUNSELOR" article written in the April 2008 issue of Sport Aviation about the landing light tripping a circuit breaker due to high resistance connections. ... > George's Reply: > Using Ohm's and Watt's laws, if a connection resistance increases, the voltage drop across that resistance increases, which increases the current draw and power demands on the circuit. The power draw of the engine and the lamp increase as voltage drops. ... > George Wilhelmsen holds a commercial certificate with an instrument rating and has more than 1,000 hours of flight experience. He has a bachelors degree in engineering technology with a background in DC, analog, and digital controls. He flies a Beech Debonair. > > End of quotes. Now this is Joe writing. The landing light in question had an electric motor to retract the light into the wing when not in use. Motors do draw more current when operated at less than design voltage. Perhaps the author understands ohm's law but just did not explain it very well. I got the impression that he was saying that a lamp uses more current if the electrical connections have higher resistance. That is not true. I wonder, could this possibly be the same George? > > -------- > Joe Gores > This is what happens when one writes an answer before s/he's had hir morning cocoa/coffee (I've done that a few times myself.) True enough, the high resistance connection does increase the voltage ~drop~ across the connection, but it is - in effect - subtracted from the voltage across the total circuit; it becomes a circuit of series loads. It's a shame that got past the proof-readers into a magazine with world-wide distribution. Dale R. COZY MkIV #0497 Ch.12; Ch's 13, 16, 22 & 23 in-progress ________________________________ Message 6 _____________________________________ Time: 10:10:07 AM PST US From: DeWitt Whittington Subject: AeroElectric-List: Vertical Power VP-50 with an Egg 3.6L engine and Z19RB At Oshkosh this year I spoke to a fellow Sportsman builder, Tim Dyer, who asked if I had considered the Vertical Power VP-50 which sells for about $1500. I knew about the VP-200 which is $6495 and had considered it out of my price range. However, after looking at the detailed data available on the VP web site, the VP-50 really does look interesting and possibly affordable since there are three of us building this Sportsman. www.verticalpower.com So I posted a question on the Vertical Power forum about using the VP-50 with the Bob Nuckolls Z19RB schematic. Here is the reply I got within 2 hours from Marc Ausman, Mr. Vertical Power: Vertical Power Join Date: Jan 2007 Posts: 223 Default VP-50 with Subaru engine You can use the VP-50 in the same manner as the VP-100 is used with the Subaru engine. In the docs section of our web site, you'll see a Subaru section. Use the VP-100 diagram as a reference - it is essentially the Z-19 diagram, but we designed it with Eggenfellner. The way we recommend wiring is as follows: - the wiring specific for the Subaru engine is handled separately from the VP system. - the VP system is used to power all the other stuff on your aircraft. - the VP system is used to monitor the voltage of both batteries. On the VP-50, use J8 pin 12 input to monitor the aux battery voltage. Reply With Quote Any thoughts from anyone else? Dee Whittington DeWitt (Dee) Whittington 406 N Mulberry St Richmond, VA 23220-3320 (804) 358-4333 phone and fax SKYPE: hilltopkid dee.whittington@gmail.com ________________________________ Message 7 _____________________________________ Time: 01:26:05 PM PST US From: "F. Tim Yoder" Subject: Re: AeroElectric-List: Search for Gremlins Hello Bob, I did as you suggested and ran a temporary ground wire from the oil pressure inst. to the crankcase. THE WIGGLE WENT AWAY! I'll remove the engine to engine mount jumpers and add a fat ground wire from the grounding buss to the crankcase per your recommendation. Your time and effort, like O.C. Baker's, sure saves a lot of us a ton of time and money. Many Thanks, Tim ----- Original Message ----- From: "Robert L. Nuckolls, III" Sent: Monday, August 18, 2008 7:17 AM Subject: Re: AeroElectric-List: Search for Gremlins > > At 11:47 PM 8/17/2008 -0400, you wrote: > > > >8/17/2008 > > > >To reply to the author, write to "F. Tim Yoder" > > > >Report on this weekends search for Gremlins; > > > >I spent several hours under the panel checking all the ground buss > >connections, breaker and switch grounds. I loosened the connections to the > >amp, volt, oil temp and oil pressure gauges, wiggled the terminals and re > >tightened. I did the same thing to the alternator and removed the regulator > >spades and replaced them.I removed the radio, cleaned the connectors and re > >installed it. I checked the ground straps from the engine to the motor > >mount. I spent some time looking for something,anything wrong. > > There should be no ground straps from engine to motor mount. Only > one fat-wire jumper from crankcase to your single-point ground on > the firewall. > > > >I started the plane and found that I had not ran off any Gremlins. When I > >turn on the Alt. the oil pressure dropped from 75# to 60# then settled on > >70#, this takes about one second. As soon as I turn off the Alt. the oil > >pressure goes back to 75#. With the radio and Alt. on the oil pressure > >needle drops a needle width when I key the radio. Again, with the Alt. off > >keying the radio does not effect the oil pressure gauge which was back to > >75#. > > > >I did not fly so I didn't have any radio issues. I think I need to find the > >cause of the apparent load on the oil pressure gauge first. > > It sounds like a ground loop issue driven by too much resistance > between crankcase and the oil pressure instrument ground. Try > removing the existing ground wire for the instrument and > grounding the instrument directly to the crankcase. > > If this makes the wiggle go away, I'll suggest you remove all > jumpers from engine to mount and add one fat-jumper between > crankcase and ground block. > > > >Oh, the Amp. meter is a little positive at idle and the voltage is showing > >a charge of about 14.4V and 13.5V with at Alt. off. > > Those numbers are right in the ballpark. > > > >I'll appreciate any suggestions. > > > >Thanks again, Tim > > Bob . . . > > ----------------------------------------) > ( . . . a long habit of not thinking ) > ( a thing wrong, gives it a superficial ) > ( appearance of being right . . . ) > ( ) > ( -Thomas Paine 1776- ) > ---------------------------------------- > > ________________________________ Message 8 _____________________________________ Time: 06:11:02 PM PST US From: "Robert L. Nuckolls, III" Subject: Re: AeroElectric-List: Search for Gremlins At 09:41 PM 8/18/2008 -0700, you wrote: Hello Bob, Thank you for your suggestions. I will try grounding the oil pressure gauge directly to the engine case and report the results. FYI, my plane is a KIS two place all composite that I have been flying for about 10 yrs. She has a little over 300 hrs. on her. This is a new problem .As far as I know .I didn't add or change any operating systems prior to these symptoms showing up. Thank You Again, Tim At 01:14 PM 8/19/2008 -0700, you wrote: > > >Hello Bob, > >I did as you suggested and ran a temporary ground wire from the oil pressure >inst. to the crankcase. THE WIGGLE WENT AWAY! > >I'll remove the engine to engine mount jumpers and add a fat ground wire >from the grounding buss to the crankcase per your recommendation. > >Your time and effort, like O.C. Baker's, sure saves a lot of us a ton of >time and money. > > Many Thanks, Tim I'm pleased that it was such a simple fix. I'm also pleased that you brought it up here on the List! In spite of our reverence for The Word according to ISO: (1) cleaning the spot where a terminal goes to structure and (2) testing with a super-duper $high$ bonding meter, there is often too little attention paid to ground system architecture. "Grounding" is probably one of the least understood technologies in vehicular systems design. It gets worse every year with new design goals by the special interest groups. One bunch of guys worry about power distribution. Another bunch worries about antenna performance. Yet another worries about lightning. Another gets paid for sifting the sands on EMC/RFI issues. Finally, there's the structures guys who are more worried about corrosion and do their best to insulate the important parts that the rest of the guys are trying to keep connected together! Fortunately for us in OBAM aircraft land, there are some pretty simple recipes for success that tend to yield consistent results over thousands of airplanes. I've tried to gather those ingredients together in chapter 5 and keep watching for new things to add. Your willingness to share your experience here validates one of the recipes and is much appreciated. Bob . . . ________________________________ Message 9 _____________________________________ Time: 06:17:23 PM PST US From: "Robert L. Nuckolls, III" Subject: Re: AeroElectric-List: Vertical Power VP-50 with an Egg 3.6L engine and Z19RB At 01:06 PM 8/19/2008 -0400, you wrote: >At Oshkosh this year I spoke to a fellow Sportsman builder, Tim Dyer, who >asked if I had considered the Vertical Power VP-50 which sells for about >$1500. I knew about the VP-200 which is $6495 and had considered it out >of my price range. However, after looking at the detailed data available >on the VP web site, the VP-50 really does look interesting and possibly >affordable since there are three of us building this >Sportsman. www.verticalpower.com >So I posted a question on the Vertical Power forum about using the VP-50 >with the Bob Nuckolls Z19RB schematic. Here is the reply I got within 2 >hours from Marc Ausman, Mr. Vertical Power: >Vertical Power > >Join Date: Jan 2007 >Posts: 223 >17d450e8.jpg VP-50 with Subaru engine >You can use the VP-50 in the same manner as the VP-100 is used with the >Subaru engine. In the docs section of our web site, you'll see a Subaru >section. Use the VP-100 diagram as a reference - it is essentially the >Z-19 diagram, but we designed it with Eggenfellner. >The way we recommend wiring is as follows: >- the wiring specific for the Subaru engine is handled separately from the >VP system. >- the VP system is used to power all the other stuff on your aircraft. >- the VP system is used to monitor the voltage of both batteries. On the >VP-50, use J8 pin 12 input to monitor the aux battery voltage. > >17d45127.jpg > >Any thoughts from anyone else? Good evening my friend. I missed getting to OSH this year but I WILL be there next year. If you still have the same cell phone number, I'll bug you as soon as I hit the field. We'll have to get together some evening. I'm quite certain that the Vertical Power products perform as advertised are well thought out and there are no safety issues. Bob . . . ________________________________ Message 10 ____________________________________ Time: 06:48:15 PM PST US From: "Robert L. Nuckolls, III" Subject: Re: AeroElectric-List: High resistance pops breaker? At 09:55 AM 8/19/2008 -0700, you wrote: > >user9253 wrote: >> >>There was a "TECHNICAL COUNSELOR" article written in the April 2008 issue >>of Sport Aviation about the landing light tripping a circuit breaker due >>to high resistance connections. >... >>George's Reply: >>Using Ohm's and Watt's laws, if a connection resistance increases, the >>voltage drop across that resistance increases, which increases the >>current draw and power demands on the circuit. The power draw of the >>engine and the lamp increase as voltage drops. >... >>George Wilhelmsen holds a commercial certificate with an instrument >>rating and has more than 1,000 hours of flight experience. He has a >>bachelors degree in engineering technology with a background in DC, >>analog, and digital controls. He flies a Beech Debonair. >> >>End of quotes. Now this is Joe writing. The landing light in question >>had an electric motor to retract the light into the wing when not in >>use. Motors do draw more current when operated at less than design >>voltage. Perhaps the author understands ohm's law but just did not >>explain it very well. I got the impression that he was saying that a >>lamp uses more current if the electrical connections have higher >>resistance. That is not true. I wonder, could this possibly be the same >>George. >> >>-------- >>Joe Gores >> > >This is what happens when one writes an answer before s/he's had hir >morning cocoa/coffee (I've done that a few times myself.) > >True enough, the high resistance connection does increase the voltage >~drop~ across the connection, but it is - in effect - subtracted from the >voltage across the total circuit; it becomes a circuit of series loads. >It's a shame that got past the proof-readers into a magazine with >world-wide distribution. It is not an automatic thing that motors draw more current as the voltage goes down. There is a motor torque constant (Kt) which is the effort delivered at the shaft stated as a ratio of torqe/amps. See: http://www.portescap.com/catalog/35GLT%20spec%20page%207.08.pdf Note the seven items under "Intrinsic Parameters". These numbers enable the designer to predict any motor's performance in a design. The item were interested in is the line labeled mNm/A or millinewton-meters per amp. Now, if the motor is driving a load where torque demand is a function of speed, then the current draw of the motor will be right in step with that function. So, let's visualize a motorized landing light. If we crank it slower, would we expect it to take more torque? Similarly, hydraulic pumps resist rotation pretty much in proportion to the pressure being exerted by the pump . . . if the flow in the system goes down due to reduced speed, would we expect the pressure to automatically get bigger? I won't say that ALL motor driven systems demand the same or more torque as speed goes down . . . but it's an unusual system. Further, it's definitely not a system that is raising or lowering a landing light against friction, gravity and air-loads. Motors slow down for two reasons, reduction in supply voltage which is linked to the Back EMF constant. If torque demands are the same, current will be the same. The motor slows down because it is loaded heavier. Torque goes up, losses in the motor terminal resistance goes up and what's left over is treated just like a reduction in supply voltage. Kt is still in play here and if the torque is high enough, it may very well cause a breaker to open. But increases in series resistance alone are almost never a recipe for tripping breakers. Now, it occurs to me that the "high resistance joint" was in fact a loose connection . . . i.e. an "intermittent low resistance joint". Here's a case where rattling a motor + lamp inrush currents MIGHT account for a continuous stressing of a breaker with a series of high current loads with a duty-cycle too low to heat up the lamp+spin the motor but sufficiently irritating to a breaker to trip it. In this case, calling it a "high-resistance joint" causes the wrong physics to be applied to the hypothetical analysis. Low average duty cycle voltage to a motor- lamp combination not only piles the admittedly high lamp inrush on top of the low back-emf of a non or very slowly spinning motor. Bob . . . ________________________________ Message 11 ____________________________________ Time: 06:48:29 PM PST US From: "Robert L. Nuckolls, III" Subject: Re: AeroElectric-List: Re: B&C alterator problem (Robert L. Nuckolls, III) > > Tell us what regulator/ov combination is installed. > If an LR3, what's the manufacturing date? If > an AEC crowbar module, what colors of wires does > it have. Older versions are red/black, newer > are orange/black. > > Bob . . . > >Bob - >Thank you for opening up the design issues I hadn't even considered. I >will return home next week and provide the more detailed information you >request. It is a B&C voltage protection device of some sort I have seen >and he used a "Z" design but I'll have to get you the specifics. Thank >you. JBB Great! Looking forward to slaying this dragon with you. Bob . . . ----------------------------------------) ( . . . a long habit of not thinking ) ( a thing wrong, gives it a superficial ) ( appearance of being right . . . ) ( ) ( -Thomas Paine 1776- ) ---------------------------------------- ------------------------------------------------------------------------------------- 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.