|
|
Hi George,
I'm not Ed, but what the heck.
http://www.matronics.com/Navigator/?AeroElectric-List to subscribe to
the AeroElectric list. You will get 20 - 30 messages per day.
http://www.aeroelectric.com/ is Bob's web site (It' really Bob N.)
Click on "Catalog of Products" to order his book and other stuff.
Bob knows his stuff. (Like Ed I prefer circuit breakers though.) Bob
is great at explaining his reasons for everything he says.
Bob W.
On Sat, 6 Jun 2009 07:39:40 +1000
"George Lendich" <lendich@aanet.com.au> wrote:
>
> Ed,
> Where do I find info on Bob K and the electronics mentioned?
> George (down under)
>
>
> Thanks, Bill
>
>
>
> Well, no doubt pot-shots will be taken by some, but for the most part, folks are appreciative to have the facts (as best I know them) as it could possibly happen to them - or some variation. Back when I first got started (1992), I really did not know Bob K and his deserved reputation. In fact, because of his view about fuses vs Circuit breakers - which I disagreed with him about at least for crucial systems - may have influence my assessment of his excellent wiring diagrams.
>
>
>
> You are correct about the alternator; I was somewhat surprised when I discovered that once my alternator (auto) starts producing voltage, pulling the field coil circuit breaker does not shut down the alternator. So your suggestion to use a modified one makes good sense.
>
>
>
> I always say you "..Live and learn - provided you live!.." I am always prepared to learn from my mistakes. So far I haven't committed the same one twice.
>
>
>
> In any case, if my "full disclosure" reporting precludes even one person from experiencing such excitement and leaves me with my "glider time" record intact - that is payback enough {:>).
>
>
>
> Ed
>
>
>
> Ed Anderson
>
> Rv-6A N494BW Rotary Powered
>
> Matthews, NC
>
> eanderson@carolina.rr.com
>
> http://www.andersonee.com
>
> http://www.dmack.net/mazda/index.html
>
> http://www.flyrotary.com/
>
> http://members.cox.net/rogersda/rotary/configs.htm#N494BW
>
> http://www.rotaryaviation.com/Rotorhead%20Truth.htm
>
>
> ------------------------------------------------------------------------------
>
> From: Rotary motors in aircraft [mailto:flyrotary@lancaironline.net] On Behalf Of Ed Anderson
> Sent: Friday, June 05, 2009 2:04 PM
> To: Rotary motors in aircraft
> Subject: [FlyRotary] Re: Ed's Electrical System was Incident 5119
>
>
>
> Hi David,
>
>
>
> You ever hear that old saying ".it seemed like a good idea at the time." ? {:>) I agree that Bob's stuff is a good place to start. I also realized exactly what you point out. While I could isolate my battery from a failed (or good for that matter {:>)) alternator - with my design, I could do nothing to isolate my essential bus from a bad battery. The only reason I can give you (10+ years later) is that I apparently viewed the alternator as the likely cause of a problem, since I swap my batteries out every two years. But, clearly a new battery short - an open circuit would not likely pose a real problem - an no essential bus power.
>
>
>
> Along those same lines of thinking, is probably why I had the battery voltage holding the master relay closed.
>
>
>
> Clearly pilot played major role in this incident from one 10 year point to the next 10 year point.
>
>
>
>
>
> Regarding the "fancy" voltmeter switch, at the time since I had two batteries and an alternator, it seemed like a good idea to be able to know the state of the three power devices. Having it just to the main circuit did not seem to provide any information on the voltage state of each battery. I like, it did not case the problem, so I'll leave it in there. No amp meter.
>
>
>
> I agree there is some rewiring in the very near future. I do find it sort of Ironic that the very thing I put in to permit me to have sufficient time (battery time) to get to an airfield - showed that it could do just that {:>). The two year old 17AH battery showed it could easily provide 30 minutes of quality voltage. It did not start to get really nasty until approx 50 minutes after launch (with two EFI and boost pumps running - I turn one EFI and boost pump off at cruise altitude).
>
>
>
> Past 50 minutes, things were clearly going to Hades in a hand basket, my EFISM showed the EC2 was still sending the correct pulse duration to injectors (based on my fuel flow reading), however, there was simply not enough voltage/power to pull the injectors completely open or for long enough. All in all I was pleased how long things did stay functional. Based on the measured voltage later on the ground (where it might have a chance to recovery some) the battery was reading six volts. So things probably continue to work/more or less down to around 7-8 volts.
>
>
>
>
>
> Some good suggestions David. One of the reasons for providing these incidents is so that folks can learn from them (self included).
>
>
>
> Ed
>
>
>
> Ed Anderson
>
> Rv-6A N494BW Rotary Powered
>
> Matthews, NC
>
> eanderson@carolina.rr.com
>
> http://www.andersonee.com
>
> http://www.dmack.net/mazda/index.html
>
> http://www.flyrotary.com/
>
> http://members.cox.net/rogersda/rotary/configs.htm#N494BW
>
> http://www.rotaryaviation.com/Rotorhead%20Truth.htm
>
>
> ------------------------------------------------------------------------------
>
> From: Rotary motors in aircraft [mailto:flyrotary@lancaironline.net] On Behalf Of David Leonard
> Sent: Friday, June 05, 2009 1:03 PM
> To: Rotary motors in aircraft
> Subject: [FlyRotary] Re: Ed's Electrical System was Incident 5119
>
>
>
> Hi Ed,
>
>
>
> Great job handling the emergency! Very nice write up. I do have to admit that you made some unusual decisions in the electrical system. None of that stuff is new, electric Bob's advice is pretty sound. I think that the "master" solenoid is often called the "battery" master for a reason - it only isolates the battery. If you want to have another battery, have another battery master that truly isolates that battery. In your system, if either battery becomes a dead short - you have just taken out your essential buss with no way to recover in flight! All your buses (essential or not) should be on the other side of the 'master' solenoids. If you want to be able to isolate the alternator, that is a separate system. (crow-bar/solenoid/field switch/fuse link/breaker/whatever). I have come to the opinion that sudden over-voltage that frys your avionics is exceedingly unlikely. I have decided to only "isolate" my alternator with a fusible link. - nice and simple that way. The alternator also connects to the buss side of the battery master solenoids. To make one of the buses 'essential' provide an alternate path around any perceived possible points of failure. Batteries fail. I have seen it in cars, I'm sure you have too. Sure, it's mostly the older type, but a good solid short across a SLA could fail it as well.
>
>
>
> I also find it unusual that your voltmeter is not simply reading the main buss voltage - no fancy switch. That way, you know what you are getting, if you know what I mean. If you want to see how one or another power source is doing, isolate the other sources from the master buss. Lastly, what about you ammeter? Does it not measure current directly from either the battery or the alternator?
>
>
>
> I'm not sure that a diode is the solution you are looking for. I think what you really need is to re-do the big wires in your system altogether. If you have settled on a one-battery system, get rid of all that extra weight and do it according to the book. From what I know, you would use a diode to 1) re-route field decay spikes back to the battery, or 2) provide alternate path from a battery to an essential (always hot) buss. (i.e. If you wanted to use a diodes, your essential buss would be connected to the other side of the master contactors via diodes, and you would use a diode from each battery to the essential buss.) So at a minimum you would want 2 diodes, one from the alternator and another from your single battery to the essential buss.
>
>
>
> I know you are a WAY better gEEk than me (i cant even spell AC). So I suspect that you already know what I am saying and you just need a kick in the arse to bite the bullet and re-do the system.
>
>
>
> Highest regards as always,
>
>
>
> --
> David Leonard
>
> Turbo Rotary RV-6 N4VY
> http://N4VY.RotaryRoster.net
> http://RotaryRoster.net
>
> On Fri, Jun 5, 2009 at 4:47 AM, Ed Anderson <eanderson@carolina.rr.com> wrote:
>
>
>
> Jim Maher was kind enough to convert the large DXF files of my electrical
> system to JPG so perhaps more of you can examine it. Recall I have removed
> the 2nd battery stuff - so ignore that on the diagrams. Also the diagram
> does not show any of the detailed EC2/injector/ignition wiring - follow
> Tracy's recommendations on that.
>
> As you will note there is no "isolation" diode between alternator and
> battery and also that the battery voltage holds the master relay closed.
> That is another change I must make. I must have decided (10+ years ago)
> that the battery would never fail - only the alternator. Clearly (now),
> without battery voltage (in my design) to hold the master relay closed -
> when the battery voltage fall to around 6-7 volts (in my case) the relay
> opens and all that good electrical power being produced by the perfectly
> good alternator - can not reach any part of the electrical system. Clearly
> NOT good as I could have continued to fly perfectly well with just the
> alternator juice.
>
> Your design is not going to be any better than the accuracy of your
> assumptions. Clearly some of my assumptions make 10 years ago definitely
> need revising.
>
> Ed
>
>
> The message is ready to be sent with the following file or link attachments:
>
> DIAG_3B.jpg
> DIAG_2B.jpg
> DIAG_1B.jpg
>
>
> Note: To protect against computer viruses, e-mail programs may prevent
> sending or receiving certain types of file attachments. Check your e-mail
> security settings to determine how attachments are handled.
>
>
> __________ Information from ESET NOD32 Antivirus, version of virus signature
> database 3267 (20080714) __________
>
> The message was checked by ESET NOD32 Antivirus.
>
>
>
> --
> Homepage: http://www.flyrotary.com/
> Archive and UnSub: http://mail.lancaironline.net:81/lists/flyrotary/List.html
>
>
>
>
>
>
>
>
>
> __________ Information from ESET NOD32 Antivirus, version of virus signature database 3267 (20080714) __________
>
> The message was checked by ESET NOD32 Antivirus.
>
> http://www.eset.com
>
--
N93BD - Rotary Powered BD-4 - http://www.bob-white.com
3.8 Hours Total Time and holding
Cables for your rotary installation - http://roblinstores.com/
|
|