AeroElectric-List Digest Archive

Sun 09/25/05


Total Messages Posted: 13



Today's Message Index:
----------------------
 
     1. 12:38 PM - FW: Wiring details for Vans 60A alternator (Glen Matejcek)
     2. 04:22 PM - Re: MAGNETO TIMING BUSS BOX PLANS (RV4WGH@AOL.COM)
     3. 05:28 PM - Alternator Speed (william rumburg)
     4. 05:58 PM - Magnetized Roll Bar (Dennis Johnson)
     5. 06:31 PM - Re: Alternator Speed (Fiveonepw@aol.com)
     6. 07:29 PM - Re: Alternator Speed (Robert L. Nuckolls, III)
     7. 07:41 PM - Re: Magnetized Roll Bar (Robert L. Nuckolls, III)
     8. 07:53 PM - ELT Antenna (Frank & Phyllis)
     9. 08:13 PM - Re: Magnetized Roll Bar (Eric M. Jones)
    10. 08:57 PM - Re: ELT Antenna (Robert L. Nuckolls, III)
    11. 09:02 PM - Re:  (Robert L. Nuckolls, III)
    12. 09:18 PM - Re: Alternator Speed (Jim Jewell)
    13. 10:45 PM - Re: Alternator Speed (Mickey Coggins)
 
 
 


Message 1


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    Time: 12:38:59 PM PST US
    From: "Glen Matejcek" <aerobubba@earthlink.net>
    Subject: FW: Wiring details for Vans 60A alternator
    --> AeroElectric-List message posted by: "Glen Matejcek" <aerobubba@earthlink.net> Glen Matejcek aerobubba@earthlink.net ----- Original Message ----- From: Glen Matejcek Subject: Wiring details for Vans 60A alternator Hi Bob et al- I've been off the list for a while and missed your original request for alternator info. As it happens, I've been doing some research into this very topic of late, and have made some interesting discoveries. First, Van's input was that the exact color of the wires in the 3 wire plug changes now and then, and shouldn't be used as a basis for wiring the alternator up. They did say that the 3 spade connectors in the plug assembly are in a 'pi' configuration, 2 blades being parallel and one at right angles. The odd blade is not used, and the 2 parallel ones are tied together and run to the ALT switch. Second, I found a high volume overhauler who seemed very knowledgeable and willing to share his expertise. According to him, that top spade in the pi, the one at right angles, in the case of vans specific unit (Vans #14684, ND unit # 14824) is the 'D' terminal, 'D' as in 'dummy'. It's not connected to anything. The left leg of the pi is the 'I' terminal. 'I' stands for 'Ignition', which is what that terminal connects to. The right leg of the pi is 'L' for 'Light', and connects to the ALT idiot light. The most interesting thing is that the labelling of the terminals has only to do with the wire routing, and not much to do with their function. The 'I' terminal is actually the voltage sense input, and in a car would be fed anytime the ignition was on. The 'L' terminal is the 'ON' signal input. It would be connected to the 'run' position of the ignition switch via the idiot light lamp. With the ignition switch in 'run', a +V signal with little or no current turns the ALT on, but won't light the lamp. With the ALT inop for any reason, the 'L' terminal goes to ground and the lamp illuminates. Curiously, this implies that a failure of the ALT lamp will cause the alternator to shut down, and without the idiot light coming on. Last, removing the +V from the 'L' terminal does shut the alternator down per it's spec. Hope this info is useful- Glen Matejcek aerobubba@earthlink.net


    Message 2


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    Time: 04:22:14 PM PST US
    From: RV4WGH@AOL.COM
    Subject: Re: MAGNETO TIMING BUSS BOX PLANS
    --> AeroElectric-List message posted by: RV4WGH@aol.com While I think the kit information that was posted is most likely the best option, I located a "how-to" article from the May 1992 issue of SPORT AVIATION, page 64, that has a schematic on how to build one. Personally, I am very fortunate to have a former field service engineer for Slick Electro who has a hangar about 200 feet from mine! HAPPY FLYING SAFELY, Wally Hunt Rockford, IL RV-4 Finishing Kit


    Message 3


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    Time: 05:28:04 PM PST US
    From: "william rumburg" <lancair403@earthlink.net>
    Subject: Alternator Speed
    --> AeroElectric-List message posted by: "william rumburg" <lancair403@earthlink.net> Alternator rpm = engine rpm X (engine pulley diameter/alternator pulley diameter). My Lycoming has the 7.5" (small) pulley and my alternator has a 2.75" pulley, which I believe to be typical. This results in alternator speeds in the 7,000 rpm range during cruise, which I believe to be excessive. A 4" diameter pulley is available for my alternator, which would reduce it's speed to the 4,000 rpm range and, I believe, produce full-rated output. I spoke with Mark Landoll who told me that alternators typically require a minimum of 1,000 rpm to produce a stable output, but he didn't know what rpm is usually required to produce full-rated output. I believe it to be in the 4,000 rpm range. He did agree that, while alternator bearings seem to hold up well to high speeds, lower speeds would produce less stress and vibration. Is anyone on the LML knowledgeable of the alternator speed typically required to produce full rated output? Bill Rumburg N403WR (Sonic bOOm)


    Message 4


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    Time: 05:58:51 PM PST US
    From: "Dennis Johnson" <pinetownd@volcano.net>
    Subject: Magnetized Roll Bar
    --> AeroElectric-List message posted by: "Dennis Johnson" <pinetownd@volcano.net> I must be missing something here regarding the magnetized roll bar. A compass needle is a magnet and magnets are attracted to iron. So a compass needle will always point towards the iron in the steel roll bar, whether it is magnetized or not. Therefore using a compass is not a method to determine if the roll bar is magnetized. To determine if it is magnetized, why not put some non-magnetized iron filings on it; if they stick, then it's magnetized, and if they don't it's not. (But I suppose that opens up the issue of how do you determine that your iron filings aren't magnetized. I suppose you could heat them to cherry red and then allow them to cool immediately prior to the test?) Note: I'm using the colloquial term "magnets are attracted to iron" because it is accurately descriptive of the current situation, knowing that a more rigorous physics explanation would be different. But the difference would not be relevant to this discussion. Dennis Johnson Lancair Legacy #257


    Message 5


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    Time: 06:31:02 PM PST US
    From: Fiveonepw@aol.com
    Subject: Re: Alternator Speed
    --> AeroElectric-List message posted by: Fiveonepw@aol.com In a message dated 09/25/2005 6:29:18 PM Central Standard Time, lancair403@earthlink.net writes: Is anyone on the LML knowledgeable of the alternator speed typically required to produce full rated output? >>> Not exactly sure of my alternator speeds, but I also have the smaller pulley on my E3D and a standard B&C L-40 and el cheapo generic regulator- no problems whatsover keeping my Panasonic 20 Ah battery fully charged at all times... From The PossumWorks in TN Mark Phillips RV-6A 235 hours & do not archive


    Message 6


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    Time: 07:29:49 PM PST US
    From: "Robert L. Nuckolls, III" <nuckollsr@cox.net>
    Subject: Re: Alternator Speed
    --> AeroElectric-List message posted by: "Robert L. Nuckolls, III" <nuckollsr@cox.net> At 08:23 PM 9/25/2005 -0400, you wrote: >--> AeroElectric-List message posted by: "william rumburg" ><lancair403@earthlink.net> > >Alternator rpm = engine rpm X (engine pulley diameter/alternator pulley >diameter). >My Lycoming has the 7.5" (small) pulley and my alternator has a 2.75" >pulley, which I believe to be typical. This results in alternator speeds in >the 7,000 rpm range during cruise, which I believe to be excessive. A 4" >diameter pulley is available for my alternator, which would reduce it's >speed to the 4,000 rpm range and, I believe, produce full-rated output. >I spoke with Mark Landoll who told me that alternators typically require a >minimum of 1,000 rpm to produce a stable output, but he didn't know what >rpm is usually required to produce full-rated output. I believe it to be in >the 4,000 rpm range. He did agree that, while alternator bearings seem to >hold up well to high speeds, lower speeds would produce less stress and >vibration. >Is anyone on the LML knowledgeable of the alternator speed typically >required to produce full rated output? Here's a typical output current curve for an automotive alternator. The population of mfgrs and part numbers will "wiggle" a bit from this curve but it's probably plus or minus 10 percent for the whole lot. http://www.aeroelectric.com/Pictures/80A_OutCurve.gif It depends on what you want . . . and what the tradeoffs are. If you'd like to have good output at ramp idle and taxi speeds (most folk really like the low speed capability in both cars and airplanes), then leave the pulley small. If you're worried about bearing and brush life, know that B&C has been selling the L40/L60 series machines for about 15 years with thousands of units in service. The first wearout in B&C history arrived back in Newton about a year ago . . . needed brushes . . . after 2200 hours in service. These alternators run nicely at over 10,000 rpm in cruise with no evidence of having "over stressed" anything due to the high speeds. If it were my airplane, I'd leave the small pulley on . . . especially if your ring gear pulley is smaller than most . . . you've already taken a hit on pre-flight output capability. Bob . . .


    Message 7


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    Time: 07:41:57 PM PST US
    From: "Robert L. Nuckolls, III" <nuckollsr@cox.net>
    Subject: Re: Magnetized Roll Bar
    --> AeroElectric-List message posted by: "Robert L. Nuckolls, III" <nuckollsr@cox.net> At 05:55 PM 9/25/2005 -0700, you wrote: >--> AeroElectric-List message posted by: "Dennis Johnson" ><pinetownd@volcano.net> > >I must be missing something here regarding the magnetized roll bar. A >compass needle is a magnet and magnets are attracted to iron. So a >compass needle will always point towards the iron in the steel roll bar, >whether it is magnetized or not. Therefore using a compass is not a >method to determine if the roll bar is magnetized. Kinda . . . sorta. If you know how to "probe" a magnetized object with a small compass, you can look for and perhaps identify two or more "poles". It's true that any ferrous material will attract EITHER end of a compass needle. >To determine if it is magnetized, why not put some non-magnetized iron >filings on it; if they stick, then it's magnetized, and if they don't it's >not. (But I suppose that opens up the issue of how do you determine that >your iron filings aren't magnetized. I suppose you could heat them to >cherry red and then allow them to cool immediately prior to the test?) Most folks in the business use a linear hall effect device or other detector of magnetic fields. >Note: I'm using the colloquial term "magnets are attracted to iron" >because it is accurately descriptive of the current situation, knowing >that a more rigorous physics explanation would be different. But the >difference would not be relevant to this discussion. The magnetized structure threads have popped up and gone dozens of times in the various interest groups for years. Having conducted magnetic effects tests in the lab for decades using plain ol' wet compasses, I can tell you that it takes one hell of a magnet to have much effect on a compass at typical separations between structure and compass. The last (and only) case I worked on an airplane was an SD20 install on Bonanzas. Turning the standby alternator on deflected the compass as much as 20 degrees on some headings . . . . this was with the compass mounted on the glare shield deck. Just moving the compass up to an already certified windshield mount reduced the effects to 2 degrees or less worst case. This was a movement of perhaps 8" vertically in the airplane. I experimented with some magnetic shielding for the rear of the SD20 and it didn't take much iron to corral the loose field flux but it would have required a re-certification of the SD20 installation. So, the lesser to two evils was move the compass a little bit. I cite this example to show (1) how the only time I've seen a problem involved a very strong magnetic source and (2) very little repositioning reduced the problem to insignificant levels. Magnetic fields like to stay very close to home and do not venture out far . . . likelihood of an inadvertent magnetization of structure being a problem is small . . . and reducing it to insignificance shouldn't be difficult. Bob . . .


    Message 8


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    Time: 07:53:14 PM PST US
    From: Frank & Phyllis <frank.phyllis@mindspring.com>
    Subject: ELT Antenna
    --> AeroElectric-List message posted by: Frank & Phyllis <frank.phyllis@mindspring.com> Is a ground plane necessary for an ELT antenna? I noticed some builders have mounted the antenna inside the tube/fabric fuselage with only a small bracket for the antenna? Why wouldn't a ground plane be needed? Frank


    Message 9


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    Time: 08:13:43 PM PST US
    From: "Eric M. Jones" <emjones@charter.net>
    Subject: Re: Magnetized Roll Bar
    --> AeroElectric-List message posted by: "Eric M. Jones" <emjones@charter.net> --> AeroElectric-List message posted by: "Dennis Johnson" <pinetownd@volcano.net> >I must be missing something here regarding the magnetized roll bar. A >compass >needle is a magnet and magnets are attracted to iron. So a compass needle >will >always point towards the iron in the steel roll bar, whether it is >magnetized >or not. Therefore using a compass is not a method to determine if the roll >bar is magnetized. >To determine if it is magnetized, why not put some non-magnetized iron >filings >on it; if they stick, then it's magnetized, and if they don't it's not. >(But >I suppose that opens up the issue of how do you determine that your iron >filings >aren't magnetized. I suppose you could heat them to cherry red and then >allow >them to cool immediately prior to the test?) >Note: I'm using the colloquial term "magnets are attracted to iron" >because it >is accurately descriptive of the current situation, knowing that a more >rigorous >physics explanation would be different. But the difference would not be >relevant >to this discussion. Dennis Johnson Lancair Legacy #257 Hi Dennis, I urge interested parties to experiment with soup cans, etc. (I'm not kidding). It is quite simple to determine if the metal can (or roll bar) is magnetized, since a non-magnetized ferromagnetic material will cause the same reaction with either the north or south end of the compass needle. But a compass needle will be wildly biased and behave differently depending on which end of the compass needle points to a magnetized metal part. Roll bars can be magnetized slowly just by sitting around, or quickly by a lightning strike, or a sudden current surge in the airframe ground, or it got that way in welding or forming. Like termites in lumber, sometimes you just buy the material that way. Regards, Eric M. Jones www.PerihelionDesign.com 113 Brentwood Drive Southbridge MA 01550-2705 (508) 764-2072 "Nothing is too wonderful to be true." James Clerk Maxwell, discoverer of electromagnetism "Too much of a good thing can be wonderful." Mae West, discoverer of personal magnetism


    Message 10


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    Time: 08:57:46 PM PST US
    From: "Robert L. Nuckolls, III" <nuckollsr@cox.net>
    Subject: Re: ELT Antenna
    --> AeroElectric-List message posted by: "Robert L. Nuckolls, III" <nuckollsr@cox.net> At 10:49 PM 9/25/2005 -0400, you wrote: >--> AeroElectric-List message posted by: Frank & Phyllis ><frank.phyllis@mindspring.com> > >Is a ground plane necessary for an ELT antenna? I noticed some builders >have mounted the antenna inside the tube/fabric fuselage with only a >small bracket for the antenna? Why wouldn't a ground plane be needed? >Frank Almost any conductor will radiate and, therefore, can be called an "antenna" too. There's been more than one individual craft some form antenna that (1) departed from the best we know how to do and/or (2) was placed in service without exploring its characteristics with instrumentation and reported "it works great for me." Bottom line is that the best we know how to do has been understood for nearly a century and yes, your skepticism is valid. Folks can probably hear his triggered ELT across the field but it's not going to work as well as it might with a more considered and well crafted installation. Bob . . .


    Message 11


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    Time: 09:02:15 PM PST US
    From: "Robert L. Nuckolls, III" <nuckollsr@cox.net>
    Subject: Re:
    --> AeroElectric-List message posted by: "Robert L. Nuckolls, III" <nuckollsr@cox.net> At 11:00 AM 9/24/2005 -0500, you wrote: >--> AeroElectric-List message posted by: "bob noffs" <icubob@newnorth.net> > >hi all, > my elec. turn coor. has a port with 3 female pins. the attachment that > was supplied that you attach the wires to is as long as my house[ well, > almost]. the turn coor. id too deep for my panel with this attachment. is > there something out there that is a right angle or is there another means > to attach the wires? i have an inch from the forward edge of the ort to > my fuel tank. > thanks in advance, bob noffs It depends on what YOU are satisfied with. You can craft some very short mating pins and solder wires to them that depart the joint at right angles to the pin. Cover with heatshrink and retain with some form of easily removed material . . . like hot glue. I think this would stay in place nicely and accomplish what you want. You'll want to avoid showing this to anyone else on your field lest the have considerable fun at your expense over the beer and pretzels. Bob . . .


    Message 12


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    Time: 09:18:30 PM PST US
    From: "Jim Jewell" <jjewell@telus.net>
    Subject: Re: Alternator Speed
    --> AeroElectric-List message posted by: "Jim Jewell" <jjewell@telus.net> Hi William, I do not remember any comments or questions on the list about the relationship between alternator pulley diameter and belt service life. During the racing days of a past life we commonly ran engines well into the 7000 RPM range. My guess is that the alternator likely exceeded twice that. Alternators where standing up to that kind of use without much complaint. Looking back now I wonder if we might have redirected at least some percentage of horse power by using a larger pulley. Turning the alternator above 12000 RPM most likely wastes energy as they don't seem to produce usable added output approaching and or beyond that. Bending the belt around a small pulley above 10,000 RPM most likely would create heat that must reduce belt life. Fan belts can take a lot of abuse. I just remembered a modified Corvair that ate the occasional belt during hard runs. Corvairs had the worst fan belt layout that I ever saw. Turning the alternator at 7000 RPM while set up in cruse should not have serious negative effects on the belt or the alternator with small pulley and the low speed (idle) performance would be of benefit. The large pulley might interfere with the cowling if you are an RV type. happy flights, Jim in Kelowna - installing windshield ----- Original Message ----- From: "william rumburg" <lancair403@earthlink.net> Subject: AeroElectric-List: Alternator Speed > --> AeroElectric-List message posted by: "william rumburg" > <lancair403@earthlink.net> > > Alternator rpm = engine rpm X (engine pulley diameter/alternator pulley > diameter). > My Lycoming has the 7.5" (small) pulley and my alternator has a 2.75" > pulley, which I believe to be typical. This results in alternator speeds > in > the 7,000 rpm range during cruise, which I believe to be excessive. A 4" > diameter pulley is available for my alternator, which would reduce it's > speed to the 4,000 rpm range and, I believe, produce full-rated output. > I spoke with Mark Landoll who told me that alternators typically require a > minimum of 1,000 rpm to produce a stable output, but he didn't know what > rpm is usually required to produce full-rated output. I believe it to be > in > the 4,000 rpm range. He did agree that, while alternator bearings seem to > hold up well to high speeds, lower speeds would produce less stress and > vibration. > Is anyone on the LML knowledgeable of the alternator speed typically > required to produce full rated output? > > Bill Rumburg > N403WR (Sonic bOOm) > > >


    Message 13


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    Time: 10:45:35 PM PST US
    From: Mickey Coggins <mick-matronics@rv8.ch>
    Subject: Re: Alternator Speed
    --> AeroElectric-List message posted by: Mickey Coggins <mick-matronics@rv8.ch> > Here's a typical output current curve for an > automotive alternator. The population of > mfgrs and part numbers will "wiggle" a bit > from this curve but it's probably plus or minus > 10 percent for the whole lot. > > http://www.aeroelectric.com/Pictures/80A_OutCurve.gif > Just a quick question - was this alternator putting out 14.something volts the whole time, or does the voltage change with the alternator speed? -- Mickey Coggins http://www.rv8.ch/ #82007 finishing do not archive




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