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  #31  
Old 01-14-2006, 07:12 AM
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robertahegy robertahegy is offline
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If you all would spend this much energy building, you all would be flying instead of arguing. Please go exercise that rivet gun instead of exercising futility.

Roberta
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  #32  
Old 01-14-2006, 08:12 AM
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Quote:
Originally Posted by gmcjetpilot
Last: you did not answer the question, what is a cheap alternator?

You throw out a condescending
"Go with a cheap alternator, and that is kinda to be expected."

What are you talking about.
What cheap alternator?
Why should we expect failure?
What kind of failure?
I take back that statement about cheap alternators, because I don't have any hard data to back it up.

All I can say is -- I read that quote about somebody having gone through 5 alternators in ~2300 hours. I know him personally and recall that he said he uses an inexpensive alternator. I don't know exactly what type, where he got it, etc. I just know it's not one of the expensive B&C ones (and yes, I agree B&C stuff is overpriced...but I still buy it for the warm fuzzies it gives me).

GMC, I'm not saying my choices are smarter or the right ones. They're the right ones for me, though. And that's what counts. These are experimental amateur built airplanes, which means you can do it your way.

Back to the topic...cooling blast tube. You can do it your way. If it gives you warm fuzzies to put in a cooling blast tube, by all means do it.

)_( Dan
RV-7 N714D
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  #33  
Old 01-15-2006, 03:52 AM
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gmcjetpilot gmcjetpilot is offline
 
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Default Warm Fuzzies back at Ya

Quote:
Originally Posted by dan
Back to the topic...cooling blast tube. You can do it your way. If it gives you warm fuzzies to put in a cooling blast tube, by all means do it. )_( Dan RV-7 N714D
As usual it turns out we where in 100% a agreement or have mutual appreciation of the other opinions in the end, after all, even if they may not be our own. Thanks Dan, I feel warm fuzzies all over my little body. It tickles. Cheers George.
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  #34  
Old 01-15-2006, 04:25 PM
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gmcjetpilot gmcjetpilot is offline
 
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Default Yes but you missed the point

Quote:
Originally Posted by jcoloccia
With all due respect, George, Pentiums have about as much in common with alternators and voltage regulators as hemp rope has in common with a joint. They're made out of the same "stuff", but I fail to see the relevance of the video as it relates to alternators. They're totally different in function and characteristics. (NOT REALLY)

On the other hand, if someone intends on installing an AMD Duron under their cowl, I think you have quite a strong case that additional cooling air is a good idea.
Boy talk about taking it literal, it is a valid point I made, and I'll explain. There is an IC chip (like a CPU) in an internal voltage regulator, and they can have and do have DIGITAL process control. Did you know that. I didn't and was surprised to see how complicated they are. They are in fact little microprocessors. Here is a spec sheet for a automotive voltage regulator IC chip: (page 2)

http://www.ortodoxism.ro/datasheets/...la/MC33099.pdf

It is no Pentium 4 (with 55 million equivalent transistors) but the voltage regulator it is way more complex than I think you might imagine. Some VR's are simple and made from a few discrete components, with a handful of transistors. However ND alterantors have fault detection, hi/lo volt warning, short protection, load dump protection, over voltage protection, timers and soft start functions to name only a few. These are things that B&C voltage regulators don't do, but urban legend has it the stock I-VR does not protect against Over Voltage (OV) or is reliable and is subject to failure. Nothing can be further from the truth. It is silly stuff. Most of these things come from old electrical systems an Cessna's or Pipers, which frankly are old 50's auto technology. There where all kind of issues. Trust me a cool ND alternator with a I-VR is many many times more reliable and stable.


Also in the VR package on an internal regulator is a field driver power transistor (separate from the IC chip): This FET or Insulated Gate Bipolar Transistor (IGBT like a power NPN) is pumping up to 4-5 amps at max output and can run hot. Again cooling is good, heat bad. Really, trust me. If you don't believe me watch the Pentium 4 blows up clip one more time. The same thing can happen to a diode, resistor, transistor or any part that exceeds its thermal limit, whether in a stereo or voltage regulator. That is the point. COOLING IS GOOD

I assume you know about electronics. So I am sure you believe "cooling is good for semi conductors". Its like CHT. Sure you can fly around at 420F all day but 380F is a lot better for the valves. Both are in the limits. Same with the voltage regulator, keep it cool it will be happier.

I guess we all will agree to dis-agree. I till say that cooling will have positive affect on reliability of alternators, especially those with on board VR's. Keep cool my Babies. That is the end of that for me. Be hot be cool do as you like. I think it is worth it. If you have a B&C I would follow their recommendations.


UNDERSTANDING THE INTERNAL VOLTAGE REGULATOR VS. EXTERNAL


The only way to do get all the advanced functions in an I-VR is with advance IC chip technology verses discrete components like a B&C VR. I am guessing the ND voltage regulator (IC) has 100's if not 100's equivalent transistors, including digital control!!!! (like a computer processor). In fact future alternators will have a digital data connection to the car's computer, but we digress. The B&C regulator is fine, but is only made with a hand full of discrete parts. It is really a true voltage regulator with something called a crow bar on top to protect from over voltage. The crow bar SHORTS itself to ground to blow a circuit breaker to stop the alternator. It works but it does it by throwing the proverbial "Crow bar" across you buss to gound. Ouch!

This is not a put down of B&C. THEY MAKE GREAT STUFF. It works and is dead simple which is an advantage, not a draw back. This is why people like B&C and Bob are comfortable with it. It works and is simple and they have been doing it this way in one form or another for 30 years. If it ain't broke don't fix it. However the auto industry has moved on, and since we rely on automotive alternators for your experimental planes, there just are not any good alternators set up for external regulation since the early 80's. Those are around but they are not up to the standards of later designs, including internal dual cooling fans. (AGAIN COOLING MADE ALTERNATORS MORE reliable.) I can't emphasise how important cooling is. Really there just are not good (small) alternators made today that don't have I-VR. So you are left with using it as is, removing it yourself, clumsy and a bit of a kludge, or going with B&C (AND COOLING IT). All valid choices.


As far as B&C and their recommendation, they are proponents of external regulation (and only sell modified ND alterantors with the VR removed). They do not speak for the internally regulated ND alternators that are in 1000's of experimental home built planes (not to mention the millions of cars). In fact they have a long standing "doctrine" of not recommending internally regulated alternators. That's cool. The thing is internal regulation is the state of the art, and if an internally regulated alternator is installed, operated as intended with in the limits (including temp), they are very reliable.


Some of the "bad luck" I-VR users can trace their issues to one of three problems: They are operating the alternator improperly (turning it on and off under load), Wired it incorrectly (not using the remote volt sense or the integral warning/fault light available on most models) and last they are buying poor quality rebuilds**. Part of the problem may be a combo of lower quality rebuilds or parts, combined with over temperature. Again COOLING.

Prove I am wrong please. B&C would love everyone to toast their ND alternator and buy their product. If I was them I also would want that. Nothing wrong with capitalism. I am not saying B&C want non B&C alternators to fail, but they are NOT advocates, or are they to be used as a source of info on how to install and use internally regulated alternators. It is not their expertise. There not going to help you, since frankly it is not a sales. Nice guys yes but internal regulator champions, no.


I have tracked many of the rumors and urban legends. If you get a good quality alternator (rebuild or new), don't turn the ALT switch on an off with the engine turning, cool it (out of conservatism and knowing cool electronics are happy electronics) and wire the warning/fault light up and remote sense (if that model has it), you will eliminate 99% of the problems I have seen.

The OV protection BTW defaults to 17 volts (not infinity as legend says). Some have had problems but it is because they don't know how the regulator works and the proper procedures to handle a "NON normal" condition. The only truly reliable way to isolate a failed alternator output (with an internal VR) is have a pull-able Circuit Breaker (CB) in the instrument panel, for on the output lead (called the b-lead). This is where wiring in the fault light comes in. It illuminates you pull the CB. It does require pilot action. 17 volts should not damage battiers or avionics, which now almost all avionics run on 10-30 volts, at least if you turn the alternator off sooner than later.

To be fair their (B&C) solution was to move the VR to a remote cooler location. Hey that works and it is an advantage, but with modern electronics and manufacturing VR's can live on a hot and vibrating alternator just fine. The ND VR has a heat sink on it for a reason. Blowing air on it (convective cooling can do wonders, see computer blowing up clip again).

Also I-VR was introduced in the 70's. No doubt the first ones are not as good. However from my research Nippondenso (ND) has one of the best designs, most protection and reliability. HOW CAN I SAY THAT? I research 30 years of The Highway safety foundation the data base for alternator issues of all brands. This is a data base that tracks all the Service bulletins, recalls, consumer complaints and accidents caused but defective automotive designs. The ND brand has a fantastic trouble free history. Not true of some other brands, Bosch, Hitachi and of course a smattering of Ford, Chrysler and Chevy alternators. ND is the best followed by Mitsubishi, IN MY OPINION.


G

** State of the automotive electrical industry, rebuild alternators:

The automotive electronics rebuild industry is getting away from rebuilding old cores. Cores are getting older now and by the time you tear it down and rebuild it, its cheaper to build a new alternator made of 100% after market parts. Now the debate is are after market parts as reliable as genuine ND parts. I have researched it and the answer is yes and no; there are many aftermarket part makers; some are better than others, but it is the wave of the future. I would not buy and use a rebuilt alternator myself if new was available. In the past new was not available at all from some models (genuine or after-market), but that's changing as the after-market has stepped up and decided to make all components. It is like the clone Lycomings. They (Superior and ECI) always made cylinders, but eventually they made more and more parts until they could make a whole engine. Same with the non-OEM auto electric part makers. The demand for alternators from the 80's and 90's is still there. New alternators for cars are so large they are not as suitable for out needs. The only new alternator from Nippondenso are the smaller industrial units or the large car alternators.

Last edited by gmcjetpilot : 01-15-2006 at 11:42 PM.
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  #35  
Old 01-15-2006, 06:31 PM
jcoloccia jcoloccia is offline
 
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Default re: exploding computers

Here's a better link with the full clips. Watch the final clip and decided for yourself if all the smoke billowing out from under the table and the "hissing" sound is from an exploading pentium or a very large firecracker (the stupid chip miraculously doesn't even "explode" in the last clip but the heat sink goes flying off...hmmm)

http://edge.i-hacked.com/make-processors-explode

Some components have lithium batteries in them, and you can make those overheat and explode by shorting out the appropriate pins (very dangerous when this happens).

Anyhow, the question isn't does it need cooling. The question is how hot can it get until it's performance/life degrades unexceptably, and how hot is it currently getting in a specific installation (if you're worried about that sort of thing). Since we're all running (or in my case will be running) installations that are different than everyone elses, I suspect that there are some that are fine with no additional cooling, and some that are being slowly cooked to death even with additional cooling.

This is why I intend to run a couple of extra wires through my firewall and into my engine monitor or fluke meter. I'll be able to temporarily install a thermocouple (or whatever) anywhere I want to answer just this sort of question if I ever feel like it. What can I say? I'm an engineer, and I like having telemetry.
__________________
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www.ballofshame.com
Former builder, but still lurking 'cause you're a pretty cool bunch...
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  #36  
Old 01-15-2006, 08:23 PM
jamiller jamiller is offline
 
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This brings up a question. I have an RV wired pretty much according to Van's plans - thus a seperate switch for the alternator field. I've been starting the engine and THEN switching on the alt field. Is this harmful to the Van's internally regulated 60 amp alternator? Or should one turn on the alt. before you start cranking?

Thanks,

John Miller
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  #37  
Old 01-15-2006, 09:39 PM
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gmcjetpilot gmcjetpilot is offline
 
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Default Great Question!!!!!!!!!!!!!!!

Quote:
Originally Posted by jamiller
This brings up a question. I have an RV wired pretty much according to Van's plans - thus a separate switch for the alternator field. I've been starting the engine and THEN switching on the alt field. Is this harmful to the Van's internally regulated 60 amp alternator? Or should one turn on the alt. before you start cranking?

Thanks,

John Miller
YES YES YES turn it on BEFORE cranking. BAD BAD BAD idea to do it after engine is running, in my opinion. This is why I take the time to write this and hope it helps you.

How does it work in a Cessna or Piper? We have all flown them right. Do you turn alternators ON and OFF separately? NO you usually turn the ALT ON with the master, before engine start and OFF with the master, after you shut the engine down.

In a car how do you start the engine and turn the alternator ON? You put the key in and turn it, first you get ignition than start. When you turn your car off you turn the key to off. As the engine revs up the alternator comes on line. When you turn the key to turn your car off, the alternator goes "off line" when it sense the IGN signal or no longer can maintain internal voltage as RPM decays. Don't get fancy with switch throwing. LET IT DO IT OWN THING, WHICH IS A SOFT START AND SOFT SHUT DOWN.

INTERNAL REGULATED ALTERNATORS are differnt than external regulated ones. They are really more sophisticated and designed to be ON at all times. The start up and shut down are automatic.

Internal VR's know how to handle coming ON line at certain voltages and off at certain voltage as RPM builds or drops off. Some have time delays and soft start (ramp voltage slowly). Not all are the same, and differnt ND alterantors have differnt characteristics. Now if the alternator is at high RPM and you tell it to "come alive" what will happen? It may deal with it. It may surge. It may just sacrifice itself to avoid a large volt/amp overshoot, burning out a component. There's NO advantage doing the extra (abrupt) step of cycling the alternator switch, none. The alternator takes so little HP to turn it is nil.

So don't turn the ALT on after start, turn it ON before cranking and leave it ON until the engine is shut down.


Anecdotal evidence/case studies: I have talked to two guys (one directly and another second hand) who had problems with their ND alterantor. The common thread was they turned there alterantors ON and OFF under load while the engine was still spinning.

In the first case the builder / pilot liked to throw switches and turned his 55 amp ND on after start and before shut down. The alternator was fine for awhile, but voltage started to become unstable. The voltage varied and dropped with load, which was above 14.5 volts (but below 16-17 volts). He also could NOT turn the alternator off using his panel switch for the ALT (IGN) as he had before. ****

****( The IGN wire on a ND alternator is NOT a FIELD wire. THE IMPORTANT POINT IS if the alternator regulator fails, the IGN wire may no longer control the VR, so you may not be able to shut it down? THE ONLY SURE METHOD TO ISOLATE THE ALTERNATOR IS TO PULL THE B-LEAD (CB). This definitively and without question will protect the aircraft and isolate the alternator, independent of anything. Some are using fuses on the B-lead and no CB as aeroelectrics suggest. I think its a bad idea. You loose a manual way to isolate the alternator.)

Also Van suggest not using an OV modules because they tend to damage alterantors. Since internal voltage regulators have OV protection already (internally, Yes they do), its not necessary in my opinion. Add on OV protection to an internally regulated alternator is a Rube Goldberg contraption, it adds weight, cost, parts and potential for nuisance trips. Again internal and external voltage regulation are different concepts, don't mix and match.



The second case the guy was flying and for some reason with all his electrics on he wanted to turn the alternator off to see if the battery would work? Really. Well when he turned the alternator back on the voltage spiked and weird things happened. He was able to turn it off again by turning the ALT switch off. The alternator was fried. What fried I don't know. I would love to get one of these abused alternators and see whats what.

What is happening? There is a big demand for power, the voltage is down to 12.6 volts or less, the alternator is spinning (fast) and has a large potential to produce lots of power, the alternator switch is thrown and the alternator surges and tries to ramp up the voltage fast. I have no exact failure mode since most guys do NOT do an analysis. Its only a theory on my part. Its based on the knowledge of the original intended application and the fact when you throw switches against how they where intended, they fail. People who leave them alone, have no problem. 1 + 1 = 2. (Note: If you get 1 + 1 = chair; stop reading).


HERE IS MY OFFER TO THE GROUP: IF THIS EVER HAPPENS TO YOU (regulator failure) PLEASE SEND YOUR REGULATOR TO ME. I HAVE CONTACTS AT A MAJOR AUTO ELECTRONICS COMPANY WHO MAKES VOLTAGE REGULATORS, AND THEY WILL DO A FAILURE ANALYSIS AND TEST IT USING SOPHISTICATED EQUIPMENT, X-RAY AND DISASSEMBLE THE REGULATOR TO SUB COMPONENTS TO FIND WHAT FAILED. Drop me a note and send me your damaged regulator. (There will be no charge to analyze your failed regulator, but you will have to pay to ship and will not get your damaged regulator back.)



HOW TO WIRE THE ND ALTERNATOR WITH INTERNAL REGULATION

Here is the way to wire it. When the master is ON, the ALT is ON. When the master is OFF, the ALT is OFF. For NON-normal conditions in the event of a failure of some kind, you should provide a way to turn the ALT off while the master is still on. This can be done with a pull-able circuit breaker (CB) or a "Cessna Style" split master switch. I don't don't like the Cessna switch, because its possible (easy) to turn the master ON without the ALT unknowingly.** At least you can't turn the ALT ON with BAT OFF which is Bad news.

I prefer a Double Poll Single Throw (DPST) toggle or Rocker switch that handles both the Master (BAT) and ALT; you know they will always be On or OFF together. In the event you need to shut the ALT lead OFF, use a pull-able CB for emergency ALT shut down. NEVER have the alternator on with the battery OFF. The DPST or Cessna Master will prevent this, and separate independent toggles or switches for the BAT and ALT are not a good idea at all, for this reason.

** (Always have a Hi/Lo volt indication (idiot light) if not the internal warning light provided by the alternator an after market warning device. Many engine monitors provide hi/lo volt warning. A volt meter is great if you check it all the time.)

Van does not recommend or show the use of the warning light (from what I hear). WHY NOT USE THIS GREAT FEATURE???? They just don't connect it to anything. That is a mistake in my opinion. Its also a fault indication, as well as high and low voltage indication. That was the way it was meant to be wired, wire it that way.

Most ND's have a plug with 2 or 3 wires: They all have IG or IGN, for ignition. The next common connection is "L" for light. This is the warning / fault light, which has varying functions between models. The next connector is "S", for remote voltage SENSE. The other wire is the large gage wire to the post, that is the output or B-lead.

Van also does not use the remote voltage sense (from what I hear). Some ND alterantors do not have remote voltage sense and use the b-lead or IGN wire to sense buss voltage. Van recommends you just tie the IGN wire and the S wire (sense wire) together (if you have a S wire, some don't). If you have a "S" wire and tie it to the IG wire, it works, but its not how it was designed.

The remote Volt-"S"ense goes direct to the battery and not the main buss. To be honest the "S" lead is more for cars that have long wire runs between the alternator, battery and fuse box. However its an input to the logic of the IC, and it uses that input to determine if things are OK. One big thing its checking for, is that the output (b-lead) is not shorted or disconnected, and it keeps the voltage at the battery more accurately controlled (as designed).

Pictures below: One is an alternator wired and another is expanded to show my no relay concept. Why have a BIG fat master relay sucking 3/4th amps of wasted power. Also most modern starters have their own relay. Why have two start relays? Some say you don't want the big battery cable HOT all the time. I think the risk is low, especially if you put a fuse on it (see my diagram). The other thing is starters with solenoids don't stick engaged like the old Bendix drive, so isolating the started is not critical.

One way to wire a ND alternator (error IGN wire should be 1 amp CB, 5 amps is not needed.) (Click to enlarge):

Here is an expanded diagram with the NO REALY concept. The master relay is a small solid state relay that only needs to handle 40 amps for example VS 400 amps. The emergency battery isolate is optional.

Even SkyTec Starters has Certified installations without a firewall Relay.

Last edited by gmcjetpilot : 01-16-2006 at 08:52 AM.
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  #38  
Old 01-16-2006, 10:12 AM
pauldan181 pauldan181 is offline
 
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Quote:


****( The IGN wire on a ND alternator is NOT a FIELD wire. THE IMPORTANT POINT IS if the alternator regulator fails, the IGN wire may no longer control the VR, so you may not be able to shut it down? THE ONLY SURE METHOD TO ISOLATE THE ALTERNATOR IS TO PULL THE B-LEAD (CB).
George,
So what does the IGN wire do if it does not provide the field voltage? You're saying that there are some failure modes where simply switching the master switch to BAT only will not kill the alternator? I have a 40 amp ND alternator and always assumed an unstable or overvoltage condition could be controlled with the master or pulling the "field" breaker. I for one am enjoying this thread
and want to understand how an alternator can produce voltage "by itself"
Thanks

Paul Danclovic
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  #39  
Old 01-16-2006, 06:19 PM
A6PILOT A6PILOT is offline
 
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Default One vote for cooling

Ive been following this thread with interest. I have blast tubes to my alternator and both mags. Why? Because Tony Bingelis said to do it in his book on engines. 900 TT hours on this RV6A - I have only flown the last 250. Don't know if the blast tubes help but they make me feel better and I don't have any cooling problems with the o320. Steve in TX
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  #40  
Old 01-16-2006, 10:23 PM
jamiller jamiller is offline
 
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Wow! Thanks, George. I much better understand now and will always turn on and off, Master and Alt. Fld., at the same time.

John Miller
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