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John Deere dynamo

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Beemer

Joined: 26 Aug 2006
Posts: 87
Location: Middle Georgia

Posted: Mon Aug 11, 2008 7:06 am Post subject: John Deere dynamo

Hi all,

I have a question concerning using a dynamo at higher engine speeds. I am looking at reducing my FWF weight, and considering some of the smaller alternator installs. I am currently using a ND IR alt, which is fine, but in lurking around, I'm becoming rather concerned about the weaknesses of these units. Unfortunately, not much else is available in this class; i.e. size and weight. All of the externally regulated alternators I've seen are much too large and heavy for my application.



I'm installing Z-13RB on my new plane, and plan on incorporating Z-24 alt disconnect contactor in line with the OV module.



However, my Suzuki G10 three cylinder runs at 5000rpm in cruise, and 5500rpm on takeoff. The JD AM877557 PM alt puts out 20amps at 2500rpm. I'm running double that. Short of re-doing my belt drive setup with a 12 inch pulley, what are the ramifications of running this little alt at these speeds? by the looks of it, the small pulley on the unit would spin it up to 10,000 rpm. I'm aware of the mechanical limits (bearings, etc), my question concerns the power output to the system. 



Any help would be much appreciated.



Bradley 

Kitfox 2/3

Middle Georgia

JD AM877557 dynamo.bmp

Description:

John Deere AM877557 dynamo

Filesize:

960.05 KB

Viewed:

1100 Time(s)

_________________
Beemer
KF2 (and now an M3!)
Suzuki G10 three-banger
Middle Georgia

nuckolls.bob(at)cox.net
Guest

Posted: Mon Aug 11, 2008 2:34 pm Post subject: John Deere dynamo

At 07:52 AM 8/11/2008 -0700, you wrote:

 	  Quote: 	
		  



Hi all,

I have a question concerning using a dynamo at higher engine speeds. I am 

looking at reducing my FWF weight, and considering some of the smaller 

alternator installs. I am currently using a ND IR alt, which is fine, but 

in lurking around, I'm becoming rather concerned about the weaknesses of 

these units.


	


   Can you give us your perceptions of "weakness"?



 	  Quote: 	
		    Unfortunately, not much else is available in this class; i.e. size and 

 weight. All of the externally regulated alternators I've seen are much 

 too large and heavy for my application.



I'm installing Z-13RB on my new plane, and plan on incorporating Z-24 alt 

disconnect contactor in line with the OV module.

   ??? I got lost here. Z-24 speaks to classic,
	


   wound field alternators like ND . . . are you

   looking for a wound field or permanent magnet

   fielded machine?



 	  Quote: 	
		  However, my Suzuki G10 three cylinder runs at 5000rpm in cruise, and 

5500rpm on takeoff. The JD AM877557 PM alt puts out 20amps at 2500rpm. I'm 

running double that. Short of re-doing my belt drive setup with a 12 inch 

pulley, what are the ramifications of running this little alt at these speeds?


	


   Mechanically, no problem. Raising the speed increased the

   AC voltage to be "rectified and regulated" down to

   14v for operating your equipment. There ARE switch-mode

   regulator designs that would handle this job nicely

   but that's a whole separate development program.



 	  Quote: 	
		    by the looks of it, the small pulley on the unit would spin it up to 

 10,000 rpm. I'm aware of the mechanical limits (bearings, etc), my 

 question concerns the power output to the system.


	


   Valid concerns as I've suggested above. Those things

   run 20-30 VAC output at 5000 rpm so you need to plan

   on 2x that at 10,000. Increasing speed is a good way

   to get more energy OUT of the PM package as long as

   the electronics can handle it but it's doubtful that

   any regulator presently exists that fill your

   requirements.



   Bob . . .

echristley(at)nc.rr.com
Guest

Posted: Mon Aug 11, 2008 5:47 pm Post subject: John Deere dynamo

Beemer wrote:

 	  Quote: 	
		   However, my Suzuki G10 three cylinder runs at 5000rpm in cruise, and 5500rpm on takeoff. The JD AM877557 PM alt puts out 20amps at 2500rpm. I'm running double that. Short of re-doing my belt drive setup with a 12 inch pulley, what are the ramifications of running this little alt at these speeds? by the looks of it, the small pulley on the unit would spin it up to 10,000 rpm. I'm aware of the mechanical limits (bearings, etc), my question concerns the power output to the system. 



 Any help would be much appreciated.

   

Have you considered running a motorcycle generator coaxially?
	




http://ernest.isa-geek.org/Delta/Pictures/EngineGeneratorParts.jpg

http://ernest.isa-geek.org/Delta/Pictures/EngineGeneratorTest.jpg

http://ernest.isa-geek.org/Delta/Pictures/EngineGeneratorMount.jpg

http://ernest.isa-geek.org/Delta/Pictures/EngineGeneratorMounted2.jpg

http://ernest.isa-geek.org/Delta/Pictures/EngineGeneratorAirIntakeAndCooling.jpg



-- 



http://www.ernest.isa-geek.org

klehman(at)albedo.net
Guest

Posted: Mon Aug 11, 2008 5:50 pm Post subject: John Deere dynamo

Bradley



I have a couple of hundred hours on a JD 20 amp PM alternator spinning 

at about 8500 rpm with the JD regulator. Occasionally up to around 

11,000 rpm.  My somewhat hazy memory is that it needs more like 6500 rpm 

to put out 20 amps. Someone (Langford??) has a website with a bunch of 

info on using these. I fitted a multi-v pulley that probably loads the 

bearings a bit less than the original single v pulley.



 From memory the unit is around 4.5 lb plus regulator compared to around 

6 lb for the conventional 40 amp ND alternator that I mentioned earlier, 

so not a big weight saver. I don't have any reason to think either is 

more reliable. In fact it seems that the JD regulator will fail if you 

start the engine with a totally dead or disconnected battery. A small OV 

relay will suffice on the JD unit instead of a heavy contactor though 

and mine is wired between the alternator and the regulator. There are 

smaller PM units available such as Kubota units.



Ken



Beemer wrote:

 	  Quote: 	
		   

 

 Hi all,

 I have a question concerning using a dynamo at higher engine speeds. I am looking at reducing my FWF weight, and considering some of the smaller alternator installs. I am currently using a ND IR alt, which is fine, but in lurking around, I'm becoming rather concerned about the weaknesses of these units. Unfortunately, not much else is available in this class; i.e. size and weight. All of the externally regulated alternators I've seen are much too large and heavy for my application.

 

 I'm installing Z-13RB on my new plane, and plan on incorporating Z-24 alt disconnect contactor in line with the OV module.

 

 However, my Suzuki G10 three cylinder runs at 5000rpm in cruise, and 5500rpm on takeoff. The JD AM877557 PM alt puts out 20amps at 2500rpm. I'm running double that. Short of re-doing my belt drive setup with a 12 inch pulley, what are the ramifications of running this little alt at these speeds? by the looks of it, the small pulley on the unit would spin it up to 10,000 rpm. I'm aware of the mechanical limits (bearings, etc), my question concerns the power output to the system. 

 

 Any help would be much appreciated.

 

 Bradley 

 Kitfox 2/3

 Middle Georgia

 

 --------

 Beemer

 KF2 (and now an M3!)

 Middle Georgia

Beemer

Joined: 26 Aug 2006
Posts: 87
Location: Middle Georgia

Posted: Tue Aug 12, 2008 5:38 am Post subject: Re: John Deere dynamo

 	  nuckolls.bob(at)cox.net wrote: 	
		  At 07:52 AM 8/11/2008 -0700, you wrote:

<snip>

>>>Can you give us your perceptions of "weakness"?

Only what I've read of your attitude/opinion (for lack of a better term) on them around the list. Correct me if I'm wrong, but I get the overall impression that you do not believe IR alternators belong on aircraft. Of course, it is possible that you don't agree with how John Q Builder tends to install them, i.e. no OV protect, no Alt disconnect contactor, etc. I get this from some old postings on the subject, and the deletion of any schematics that show IR alternator installations. I should add that there isn't much available for my type of engine (Geo Metro auto conversion), and weight is a significant issue up on the nose of the Kitfox.

 	  Quote: 	
		  <snip>

   >>> ??? I got lost here. Z-24 speaks to classic,

   >>>wound field alternators like ND . . . are you

   >>>looking for a wound field or permanent magnet

   >>>fielded machine?

What I'm looking for, ultimately, is to shave about 10lbs from the nose of my aircraft. To that end, I'm exploring options for various components. More specifically, I'm looking for 20-40 reliable amps for my electrically dependent FI engine. Beyond that, I'm open to suggestions.

I was referring to the old Z-24 that depicted the alternator disconnect contactor for the IR alternator, driven by the alt field wire, that completely disconnects the alternator from the battery (system) in case of OV condition. That's what I'm running now on my current install. The note on the new Z-24 again leads me to believe you are not in favor of IR alternators on aircraft. Again, correct me if I'm wrong here.

 	  Quote: 	
		  <snip>

   >>> Mechanically, no problem. Raising the speed increased the

   >>>AC voltage to be "rectified and regulated" down to

   >>>14v for operating your equipment. There ARE switch-mode

   >>>regulator designs that would handle this job nicely

   >>> but that's a whole separate development program.

That's why I'm asking. I should point out that I'm not very electrically/electronically savvy (..got to know my limitations). That's why you, this list, and Aeroelectric.com are such valuable resources for me. I'm asking the advice of those much smarter than I on such things.

 	  Quote: 	
		  <snip>

   >>>Valid concerns as I've suggested above. Those things

   >>>run 20-30 VAC output at 5000 rpm so you need to plan

   >>>on 2x that at 10,000. Increasing speed is a good way

   >>>to get more energy OUT of the PM package as long as

   >>>the electronics can handle it but it's doubtful that

   >>>any regulator presently exists that fill your

   >>>requirements.

   >>>

   >>>Bob . . .

My electronics are minimal. I'm running an EFIS that draws about 100mA max, my GPS and Radio are handhelds that are plugged in to charge, and a small portable intercom. I've got Kuntzleman strobes and LED Navs, and two 55watt landing lights. If it all dies, my pressure driven AoA gives me speed, and a ball keeps me centered, the rest is VFR (blue up/brown down). GPS gets me to "Nearest", and my radio will last a while all by itself. I'm strictly Day VFR, with no provision or desire to night or IFR. Night someday, NEVER IFR in this plane. So my number one concern is keeping the EFI and fuel pump running. My new plane will have Z-13RB installed to this end. I don't even plan to put in the endurance bus, as I've got nothing that needs it. It even works to the end of having the second small battery in the back to help offset the CG of the heavier engine, rather than just putting in dead weight.

In the end, I think the JD dynamo will not be cost effective. For what they cost, I'd be shelling out $40 per lb for the weight savings. Probably not worth it overall.

Bradley

_________________
Beemer
KF2 (and now an M3!)
Suzuki G10 three-banger
Middle Georgia

nuckolls.bob(at)cox.net
Guest

Posted: Wed Aug 13, 2008 3:33 pm Post subject: John Deere dynamo

At 06:38 AM 8/12/2008 -0700, you wrote:

 	  Quote: 	

nuckolls.bob(at)cox.net wrote:

 > At 07:52 AM 8/11/2008 -0700, you wrote:

 >

 > > >>>Can you give us your perceptions of "weakness"?

Only what I've read of your attitude/opinion (for lack of a better term) 

on them around the list. Correct me if I'm wrong, but I get the overall 

impression that you do not believe IR alternators belong on aircraft.

   That's a popular myth promulgated mostly by two individuals

   who are demonstrably un-qualified to judge my work.

   They appear to have never read and/or understood design

   goals I (and hundreds of my colleagues) have embraced as

   aircraft system integrators and component designers for 30+ years.

 	  Quote: 	
		    Of course, it is possible that you don't agree with how John Q Builder 

 tends to install them, i.e. no OV protect, no Alt disconnect contactor, 

 etc. I get this from some old postings on the subject, and the deletion 

 of any schematics that show IR alternator installations. I should add 

 that there isn't much available for my type of engine (Geo Metro auto 

 conversion), and weight is a significant issue up on the nose of the Kitfox.

   I'm not sure you understand the spirit and intent of

   my offerings here on the List and elsewhere. I think we

   can agree that airplanes, with all the potential for

   utility and pleasure, are exceedingly unforgiving machines.

   The environment in which we operate them can be equally

   unforgiving. Everything I've bolted to an airplane has

   these design goals in mind. (1) Utility (function as

   specified/advertised). (2) Weight. (3) Cost of ownership.

   and last but not least (4) Risk Mitigation.

   In categories 1-3, the stock automotive alternator is

   a stellar performer and quite suited to the task aboard

   airplanes but with two shortcomings"

   In the category of UTILITY: ON/OFF control at any time

   under any conditions without risk to itself or other

   components in the system. This is how alternators/generators

   have functioned in aircraft since day-one. There are both

   operational and risk mitigation advantages for giving the pilot

   and OV protection systems a means of managing alternator operations . . .

   and RISK MITIGATION: I have seen no design to data for

   which the risk of OV runaway is zero. Further, the potential

   for a high-energy even in a runaway alternator is significant.

   See:

http://aeroelectric.com/articles/When_is_110V_not_Over_Voltage.pdf

   Since day one in aircraft, independent monitoring of bus voltage

   COMBINED with the ability to shut an alternator/generator off

   at will relieves the system designer of a time-consuming

   and costly effort of designing, proving and maintaining a system

   reliability in the 10-to-the-minus-9-failures-per-flight-hour

   category (FAA-speak for 'never happens').

   Failure tolerance is integral to every design and goes directly

   to both Cost of Ownership and Risk Mitigation.

   Example: I'm working on a line of smart actuators that communicate

   on serial data busses, move flight surfaces, and while failure to

   move does not generate a serious situation for aircraft and

   crew, a failure that produces an un-commanded is bad. The neat

   thing is that there are flight systems management computers

   on all these aircraft that control everything. Hence Level-A

   qualification for software. Normally, an actuator such as

   we've proposed would require Level-A qualification too . . .

   except.

   Since Level-A software already exists that sends me commands

   and monitors my response to those commands, all I need to

   do is place the entire monitoring duties on the machines already

   endowed with the ability to monitor abnormal behavior. I

   provide a hard discrete enable line to that computer that

   actually powers the level shifters between low level logic

   and the motor drivers. If that 28v disappears, the actuator

   cannot move.

   Now, my software can be crafter to Level-C or even Level-D

   because it has no ability to generate hazardous conditions

   that are not already being monitored and controlled by another

   part of the system qualified to Level-A.

   By making my part of the program failure tolerant without

   adding risk to the overall flight system, costs of ownership

   goes down, and parts-count goes down (driving reliability

   up). But even if my gizmo craps every 1000 hours, it's not

   a safety of flight issue - only a cost of ownership issue.

  >

 	  Quote: 	
		   >    >>> ??? I got lost here. Z-24 speaks to classic,

 >    >>>wound field alternators like ND . . . are you

 >    >>>looking for a wound field or permanent magnet

 >    >>>fielded machine?

What I'm looking for, ultimately, is to shave about 10lbs from the nose of 

my aircraft. To that end, I'm exploring options for various components. 

More specifically, I'm looking for 20-40 reliable amps for my electrically 

dependent FI engine. Beyond that, I'm open to suggestions.

   If I were building an airplane, it WOULD have a

   stock automotive alternator with Z-24 installed as

   an interim solution to get flying and laying the

   ground work for installation of a permanent solution

   at a later date as described in:

http://www.aeroelectric.com/articles/Adapting_IR_Alternators_to_Aircraft.pdf

 	  Quote: 	
		  I was referring to the old Z-24 that depicted the alternator disconnect 

contactor for the IR alternator, driven by the alt field wire, that 

completely disconnects the alternator from the battery (system) in case of 

OV condition. That's what I'm running now on my current install. The note 

on the new Z-24 again leads me to believe you are not in favor of IR 

alternators on aircraft. Again, correct me if I'm wrong here.

   Why would I have even crafted Z-24 if I were attempting

   to quash the use of IR alternators? And why would I

   follow up the Z-24 interim with the new-and-improved

   alternative? I'll suggest that these two drawings are

   a positive if not enthusiastic endorsement of the

   value offered by a host of automotive alternator

   products.

   No, I have never said that IR alternators do not belong

   on aircraft. I have said that I cannot RECOMMEND them because

   the current state of our art does not allow me to integrate

   them in satisfaction of the design goals cited above.

   Z-24 was a first crack at meeting those design goals.

   It has some short comings which are discussed in detail in

   publications on my website. Those short comings will

   be addressed in due course.

 	  Quote: 	

 >    >>> Mechanically, no problem. Raising the speed increased the

 >    >>>AC voltage to be "rectified and regulated" down to

 >    >>>14v for operating your equipment. There ARE switch-mode

 >    >>>regulator designs that would handle this job nicely

 >    >>> but that's a whole separate development program.

 >

That's why I'm asking. I should point out that I'm not very 

electrically/electronically savvy (..got to know my limitations). That's 

why you, this list, and Aeroelectric.com are such valuable resources for 

me. I'm asking the advice of those much smarter than I on such things.

   First, there are ways to make ANY selection of engine driven

   power source suited to use in the aircraft environment.

   Further, if you choose not to embrace my design goals, then

   there is still good value to be received from bolting a stock

   automotive alternator to your airplane. As long as you

   understand and accept the risks and perhaps lack of utility

   compared to the majority of the GA fleet, then I have

   no heartburn with it. But if you're being mis-advised into

   believing there is little or no increased risks as

   compared to contemporary aircraft design philosophies,

   you owe it to yourself to at least elevate your understanding

   to the level needed to make a well considered decision.

   Don't do anything based on my (or anyone else's recommendations)

   unless you understand and personally embrace the design

   goals that go along with those recommendations.

 	  Quote: 	
		  My electronics are minimal. I'm running an EFIS that draws about 100mA 

max, my GPS and Radio are handhelds that are plugged in to charge, and a 

small portable intercom. I've got Kuntzleman strobes and LED Navs, and two 

55watt landing lights. If it all dies, my pressure driven AoA gives me 

speed, and a ball keeps me centered, the rest is VFR (blue up/brown down). 

GPS gets me to "Nearest", and my radio will last a while all by itself. 

I'm strictly Day VFR, with no provision or desire to night or IFR. Night 

someday, NEVER IFR in this plane. So my number one concern is keeping the 

EFI and fuel pump running. My new plane will have Z-13RB installed to this 

end. I don't even plan to put in the endurance bus, as I've got nothing 

that needs it. It even works to the end of having the second small battery 

in the back to help offset the CG of the heavier engine, rather than just 

putting in dead weight.

   Sounds like a 3.5# SD-8 would do nicely for you. There are

   thousands of LongEz and VariEz aircraft flying with this

   machine as the only source of engine driven power.

 	  Quote: 	
		  In the end, I think the JD dynamo will not be cost effective. For what 

they cost, I'd be shelling out $40 per lb for the weight savings. Probably 

not worth it overall.

   But if you wanted to put a little 35 or 40A wound

   field alternator on, that would not be a bad

   decision either . . . internally or externally

   regulated.

   Let's channel this discussion toward establishing

   your design goals and then meeting them. Please set

   aside any notions that I or anyone else here on the

   list is going to twist your arm to do anything except

   perhaps those things which are overtly foolhardy or

   dangerous.

   Have you completed a load analysis of just what

   your energy requirements are?

   See:

http://www.aeroelectric.com/PPS/Load_Analysis/Blank_Form.pdf

   This form is designed to facilitate a study of your

   true energy needs. Until those are known, may I

   suggest that alternator selection for the purpose

   of minimizing weight is premature?

   Bob . . .

Beemer

Joined: 26 Aug 2006
Posts: 87
Location: Middle Georgia

Posted: Thu Aug 14, 2008 1:15 pm Post subject: Re: John Deere dynamo

 	  nuckolls.bob(at)cox.net wrote: 	
		  At 06:38 AM 8/12/2008 -0700, you wrote:



<snip>



   That's a popular myth promulgated mostly by two individuals

   who are demonstrably un-qualified to judge my work.

   They appear to have never read and/or understood design

   goals I (and hundreds of my colleagues) have embraced as

   aircraft system integrators and component designers for 30+ years. 	
  



Well, my design goals are different than someone building a Lancair IV. They are also different than Cessna's. I think the overall objective should be the same - supply me 12 volts and don't hurt me. I see that you are leading us toward this objective.



I have no desire to re-hash opinion differences nor point fingers. I want to wire my Kitfox.



<snip>



 	  Quote: 	
		  

   I'm not sure you understand the spirit and intent of

   my offerings here on the List and elsewhere. I think we

   can agree that airplanes, with all the potential for

   utility and pleasure, are exceedingly unforgiving machines.

   The environment in which we operate them can be equally

   unforgiving. Everything I've bolted to an airplane has

   these design goals in mind. (1) Utility (function as

   specified/advertised). (2) Weight. (3) Cost of ownership.

   and last but not least (4) Risk Mitigation.



   In categories 1-3, the stock automotive alternator is

   a stellar performer and quite suited to the task aboard

   airplanes but with two shortcomings"



   In the category of UTILITY: ON/OFF control at any time

   under any conditions without risk to itself or other

   components in the system. This is how alternators/generators

   have functioned in aircraft since day-one. There are both

   operational and risk mitigation advantages for giving the pilot

   and OV protection systems a means of managing alternator operations . . .



   and RISK MITIGATION: I have seen no design to data for

   which the risk of OV runaway is zero. Further, the potential

   for a high-energy even in a runaway alternator is significant.

   See:



http://aeroelectric.com/articles/When_is_110V_not_Over_Voltage.pdf



   Since day one in aircraft, independent monitoring of bus voltage

   COMBINED with the ability to shut an alternator/generator off

   at will relieves the system designer of a time-consuming

   and costly effort of designing, proving and maintaining a system

   reliability in the 10-to-the-minus-9-failures-per-flight-hour

   category (FAA-speak for 'never happens').



   Failure tolerance is integral to every design and goes directly

   to both Cost of Ownership and Risk Mitigation.



   <snip>



   By making my part of the program failure tolerant without

   adding risk to the overall flight system, costs of ownership

   goes down, and parts-count goes down (driving reliability

   up). But even if my gizmo craps every 1000 hours, it's not

   a safety of flight issue - only a cost of ownership issue.

 

	
 



I don't see any debate here. I'm not a fan of the "more is better" philosophy. KISS is the rule on the K'fox. I'm agonizing over following Z-19RB, but with my EFI engine, I feel the redundancy outweighs the complicity.



<snip> 



 	  Quote: 	
		  

   If I were building an airplane, it WOULD have a

   stock automotive alternator with Z-24 installed as

   an interim solution to get flying and laying the

   ground work for installation of a permanent solution

   at a later date as described in:



http://www.aeroelectric.com/articles/Adapting_IR_Alternators_to_Aircraft.pdf



	




Wow. Telling statement, that. It quite well answers the question "What would Bob do...?"



 	  Quote: 	
		  



   Why would I have even crafted Z-24 if I were attempting

   to quash the use of IR alternators? And why would I

   follow up the Z-24 interim with the new-and-improved

   alternative? I'll suggest that these two drawings are

   a positive if not enthusiastic endorsement of the

   value offered by a host of automotive alternator

   products.



   No, I have never said that IR alternators do not belong

   on aircraft. I have said that I cannot RECOMMEND them because

   the current state of our art does not allow me to integrate

   them in satisfaction of the design goals cited above.

   Z-24 was a first crack at meeting those design goals.

   It has some short comings which are discussed in detail in

   publications on my website. Those short comings will

   be addressed in due course.

	




But you just said you would use one, yet not recommend one. Am I mis-interpreting this somehow?



<snip>

 	  Quote: 	
		  

   First, there are ways to make ANY selection of engine driven

   power source suited to use in the aircraft environment.

   Further, if you choose not to embrace my design goals, then

   there is still good value to be received from bolting a stock

   automotive alternator to your airplane. As long as you

   understand and accept the risks and perhaps lack of utility

   compared to the majority of the GA fleet, then I have

   no heartburn with it. But if you're being mis-advised into

   believing there is little or no increased risks as

   compared to contemporary aircraft design philosophies,

   you owe it to yourself to at least elevate your understanding

   to the level needed to make a well considered decision.

   Don't do anything based on my (or anyone else's recommendations)

   unless you understand and personally embrace the design

   goals that go along with those recommendations.



	




By installing Z-13RB with Z-24 integrated, I'm providing for the bad alternator all together, by disconnecting it from the system entirely. From then on, I am carried by the battery(s), and need to design enough ah margin to get me home or nearest, anyway.



 	  Quote: 	
		  

   Sounds like a 3.5# SD-8 would do nicely for you. There are

   thousands of LongEz and VariEz aircraft flying with this

   machine as the only source of engine driven power.

	




Ummm, I'm sure they're great units, and would do fine. But I can't use the gear drive.

 

<snip>



 	  Quote: 	
		  

   But if you wanted to put a little 35 or 40A wound

   field alternator on, that would not be a bad

   decision either . . . internally or externally

   regulated.



   Let's channel this discussion toward establishing

   your design goals and then meeting them. Please set

   aside any notions that I or anyone else here on the

   list is going to twist your arm to do anything except

   perhaps those things which are overtly foolhardy or

   dangerous.



   Have you completed a load analysis of just what

   your energy requirements are?



   See:



http://www.aeroelectric.com/PPS/Load_Analysis/Blank_Form.pdf



   This form is designed to facilitate a study of your

   true energy needs. Until those are known, may I

   suggest that alternator selection for the purpose

   of minimizing weight is premature?



   Bob . . . 	


No ones talking me into anything. I'm trying to decide how to proceed on my new airplane.



I haven't analyzed it. I have no idea how to check the ECM and coil draw. Right now I have 55amps, Z-24, and 17ah running the motor just fine. I have two readily available alternator options, both 40amp, one weighs 6.5lbs, the other 4.5 lbs. I'm just trying to figure out if there's a better way to wire up the new airplane. If I can install the JD dynamo with external reg, spin it up to 9000rpm, and live to tell the tale, I'll consider it on its merits. But I would like to know if it's feasible to do so, or a bad choice due to something I'm not being told by the advertising.



Bradley

_________________
Beemer
KF2 (and now an M3!)
Suzuki G10 three-banger
Middle Georgia

ed(at)muellerartcover.com
Guest

Posted: Thu Aug 14, 2008 3:44 pm Post subject: John Deere dynamo

If you have the engine actually running, can't you turn all the other  

electrics off and measure the draw of the ECM and coil?



Ed

On Aug 14, 2008, at 5:15 PM, Beemer wrote:



 	  Quote: 	
		   

 nuckolls.bob(at)cox.net wrote:

> At 06:38 AM 8/12/2008 -0700, you wrote:

>

>    That's a popular myth promulgated mostly by two individuals

>    who are demonstrably un-qualified to judge my work.

>    They appear to have never read and/or understood design

>    goals I (and hundreds of my colleagues) have embraced as

>    aircraft system integrators and component designers for 30+ years.

 Well, my design goals are different than someone building a Lancair  

 IV. They are also different than Cessna's. I think the overall  

 objective should be the same - supply me 12 volts and don't hurt me. I  

 see that you are leading us toward this objective.



 I have no desire to re-hash opinion differences nor point fingers. I  

 want to wire my Kitfox.





>

>    I'm not sure you understand the spirit and intent of

>    my offerings here on the List and elsewhere. I think we

>    can agree that airplanes, with all the potential for

>    utility and pleasure, are exceedingly unforgiving machines.

>    The environment in which we operate them can be equally

>    unforgiving. Everything I've bolted to an airplane has

>    these design goals in mind. (1) Utility (function as

>    specified/advertised). (2) Weight. (3) Cost of ownership.

>    and last but not least (4) Risk Mitigation.

>

>    In categories 1-3, the stock automotive alternator is

>    a stellar performer and quite suited to the task aboard

>    airplanes but with two shortcomings"

>

>    In the category of UTILITY: ON/OFF control at any time

>    under any conditions without risk to itself or other

>    components in the system. This is how alternators/generators

>    have functioned in aircraft since day-one. There are both

>    operational and risk mitigation advantages for giving the pilot

>    and OV protection systems a means of managing alternator  

> operations . . .

>

>    and RISK MITIGATION: I have seen no design to data for

>    which the risk of OV runaway is zero. Further, the potential

>    for a high-energy even in a runaway alternator is significant.

>    See:

>

> http://aeroelectric.com/articles/When_is_110V_not_Over_Voltage.pdf

>

>    Since day one in aircraft, independent monitoring of bus voltage

>    COMBINED with the ability to shut an alternator/generator off

>    at will relieves the system designer of a time-consuming

>    and costly effort of designing, proving and maintaining a system

>    reliability in the 10-to-the-minus-9-failures-per-flight-hour

>    category (FAA-speak for 'never happens').

>

>    Failure tolerance is integral to every design and goes directly

>    to both Cost of Ownership and Risk Mitigation.

>

>    By making my part of the program failure tolerant without

>    adding risk to the overall flight system, costs of ownership

>    goes down, and parts-count goes down (driving reliability

>    up). But even if my gizmo craps every 1000 hours, it's not

>    a safety of flight issue - only a cost of ownership issue.

 I don't see any debate here. I'm not a fan of the "more is better"  

 philosophy. KISS is the rule on the K'fox. I'm agonizing over  

 following Z-19RB, but with my EFI engine, I feel the redundancy  

 outweighs the complicity.





>

>    If I were building an airplane, it WOULD have a

>    stock automotive alternator with Z-24 installed as

>    an interim solution to get flying and laying the

>    ground work for installation of a permanent solution

>    at a later date as described in:

>

> http://www.aeroelectric.com/articles/ 

> Adapting_IR_Alternators_to_Aircraft.pdf

 Wow. Telling statement, that. It quite well answers the question "What  

 would Bob do...?"

>

>

>    Why would I have even crafted Z-24 if I were attempting

>    to quash the use of IR alternators? And why would I

>    follow up the Z-24 interim with the new-and-improved

>    alternative? I'll suggest that these two drawings are

>    a positive if not enthusiastic endorsement of the

>    value offered by a host of automotive alternator

>    products.

>

>    No, I have never said that IR alternators do not belong

>    on aircraft. I have said that I cannot RECOMMEND them because

>    the current state of our art does not allow me to integrate

>    them in satisfaction of the design goals cited above.

>    Z-24 was a first crack at meeting those design goals.

>    It has some short comings which are discussed in detail in

>    publications on my website. Those short comings will

>    be addressed in due course.

>

 But you just said you would use one, yet not recommend one. Am I  

 mis-interpreting this somehow?



>

>    First, there are ways to make ANY selection of engine driven

>    power source suited to use in the aircraft environment.

>    Further, if you choose not to embrace my design goals, then

>    there is still good value to be received from bolting a stock

>    automotive alternator to your airplane. As long as you

>    understand and accept the risks and perhaps lack of utility

>    compared to the majority of the GA fleet, then I have

>    no heartburn with it. But if you're being mis-advised into

>    believing there is little or no increased risks as

>    compared to contemporary aircraft design philosophies,

>    you owe it to yourself to at least elevate your understanding

>    to the level needed to make a well considered decision.

>    Don't do anything based on my (or anyone else's recommendations)

>    unless you understand and personally embrace the design

>    goals that go along with those recommendations.

 By installing Z-13RB with Z-24 integrated, I'm providing for the bad  

 alternator all together, by disconnecting it from the system entirely.  

 From then on, I am carried by the battery(s), and need to design  

 enough ah margin to get me home or nearest, anyway.

>

>    Sounds like a 3.5# SD-8 would do nicely for you. There are

>    thousands of LongEz and VariEz aircraft flying with this

>    machine as the only source of engine driven power.

>

 Ummm, I'm sure they're great units, and would do fine. But I can't use  

 the gear drive.





>

>    But if you wanted to put a little 35 or 40A wound

>    field alternator on, that would not be a bad

>    decision either . . . internally or externally

>    regulated.

>

>    Let's channel this discussion toward establishing

>    your design goals and then meeting them. Please set

>    aside any notions that I or anyone else here on the

>    list is going to twist your arm to do anything except

>    perhaps those things which are overtly foolhardy or

>    dangerous.

>

>    Have you completed a load analysis of just what

>    your energy requirements are?

>

>    See:

>

> http://www.aeroelectric.com/PPS/Load_Analysis/Blank_Form.pdf

>

>    This form is designed to facilitate a study of your

>    true energy needs. Until those are known, may I

>    suggest that alternator selection for the purpose

>    of minimizing weight is premature?

>

>    Bob . . .



 No ones talking me into anything. I'm trying to decide how to proceed  

 on my new airplane.



 I haven't analyzed it. I have no idea how to check the ECM and coil  

 draw. Right now I have 55amps, Z-24, and 17ah running the motor just  

 fine. I have two readily available alternator options, both 40amp, one  

 weighs 6.5lbs, the other 4.5 lbs. I'm just trying to figure out if  

 there's a better way to wire up the new airplane. If I can install the  

 JD dynamo with external reg, spin it up to 9000rpm, and live to tell  

 the tale, I'll consider it on its merits. But I would like to know if  

 it's feasible to do so, or a bad choice due to something I'm not being  

 told by the advertising.



 Bradley



 --------

 Beemer

 KF2 (and now an M3!)

 Middle Georgia





 Read this topic online here:



 http://forums.matronics.com/viewtopic.php?p=198613#198613

nuckolls.bob(at)cox.net
Guest

Posted: Thu Aug 14, 2008 4:51 pm Post subject: John Deere dynamo

 	  Quote: 	
		  

I have no desire to re-hash opinion differences nor point fingers. I want 

to wire my Kitfox.


	


   Understood.



 	  Quote: 	
		  



I don't see any debate here. I'm not a fan of the "more is better" 

philosophy. KISS is the rule on the K'fox. I'm agonizing over following 

Z-19RB, but with my EFI engine, I feel the redundancy outweighs the complicity.


	


   No debated intended. Are you interested in any time, any

   conditions ON/OFF and/or ov protection for your alternator

   of choice?



 	  Quote: 	
		   >    If I were building an airplane, it WOULD have a

 >    stock automotive alternator with Z-24 installed as

 >    an interim solution to get flying and laying the

 >    ground work for installation of a permanent solution

 >    at a later date as described in:

 >

 > 

 http://www.aeroelectric.com/articles/Adapting_IR_Alternators_to_Aircraft.pdf

 >

 >

Wow. Telling statement, that. It quite well answers the question "What 

would Bob do...?"


	


   Or anyone else who is interested in design goals cited . . .



 	  Quote: 	
		   >

 >

 >    Why would I have even crafted Z-24 if I were attempting

 >    to quash the use of IR alternators? And why would I

 >    follow up the Z-24 interim with the new-and-improved

 >    alternative? I'll suggest that these two drawings are

 >    a positive if not enthusiastic endorsement of the

 >    value offered by a host of automotive alternator

 >    products.

 >

 >    No, I have never said that IR alternators do not belong

 >    on aircraft. I have said that I cannot RECOMMEND them because

 >    the current state of our art does not allow me to integrate

 >    them in satisfaction of the design goals cited above.

 >    Z-24 was a first crack at meeting those design goals.

 >    It has some short comings which are discussed in detail in

 >    publications on my website. Those short comings will

 >    be addressed in due course.

 >

But you just said you would use one, yet not recommend one. Am I 

mis-interpreting this somehow?


	


    The time when I was unable to recommend them was BEFORE Z-24

    was crafted . . . I've designed dozens of engine driven power

    systems for both OBAM and TC aircraft. Until about 10 years

    ago, the alternators of choice were externally regulated . . .

    but mostly because that's the way we've been doing it for

    quite some time.



    The IR alternator was obviously future king-of-the-market

    even in airplanes. The challenge was to figure out how

    one could take any size, any brand, any pedigree IR

    alternator and integrate it into an aircraft while not

    giving up control and protection philosophies that have

    served us well.



    Z-24 was the first crack at it . . . but if the pilot

    operates the system to turn the alternator OFF while

    it's running loaded and at RPM, then there was risk

    of a load-dump transient killing the alternator's own

    regulator. A few folks experienced this unhappy event

    which did place a cloud over the Z-24 control/protection

    philosophy.



    We went back to the drawing board and crafted a product

    that will drop into an existing Z-24 installation that

    takes care of the load-dump, protects the el-cheeso

    contactor from arcing, provides any time, any

    conditions ON/OFF control -AND- OV protection in

    a single product.

 	  Quote: 	
		  By installing Z-13RB with Z-24 integrated, I'm providing for the bad 

alternator all together, by disconnecting it from the system entirely. 

 From then on, I am carried by the battery(s), and need to design enough 

ah margin to get me home or nearest, anyway.


	


    Yes, as long as you don't exercise the ON/OFF switch

    except at low rpm (pre takeoff, pre parking) then

    Z-24 does offer OV protection.



 	  Quote: 	
		   >

 >    Sounds like a 3.5# SD-8 would do nicely for you. There are

 >    thousands of LongEz and VariEz aircraft flying with this

 >    machine as the only source of engine driven power.

 >

Ummm, I'm sure they're great units, and would do fine. But I can't use the 

gear drive.


	


    I didn't grasp until now that you were running an

    automotive conversion . . . okay, how about the 3.5

    pound cousin to the SD-8



http://aeroelectric.com/Pictures/Alternators/Kubota.jpg



    This critter is good for about 12-15A when turned

    fast enough and assuming that the companion regulator-

    rectifier isn't over-stressed by the higher input

    operating voltage.  I've prayed a bit over the

    schematics for an exemplar device . . .



http://aeroelectric.com/Pictures/Schematics/3-Phase_PM_Rectifier_Regulator.gif



    . . . and it seems likely that the device would

    tolerate the higher rpm. In a few months, I'll have

    a drive stand up and running and will be able to

    test the hypothesis in the shop. If you're willing

    to invest in the experiment, you can supply results

    that would be of interest to lots of other folks

    here on the List.



 	  Quote: 	
		  I haven't analyzed it. I have no idea how to check the ECM and coil draw. 

Right now I have 55amps, Z-24, and 17ah running the motor just fine. I 

have two readily available alternator options, both 40amp, one weighs 

6.5lbs, the other 4.5 lbs. I'm just trying to figure out if there's a 

better way to wire up the new airplane. If I can install the JD dynamo 

with external reg, spin it up to 9000rpm, and live to tell the tale, I'll 

consider it on its merits. But I would like to know if it's feasible to do 

so, or a bad choice due to something I'm not being told by the advertising.


	


   The risks for trying are low. The regulator's stability

   might be less than idea and/or the regulator could fail due

   to higher than design voltage. As long as you have OV protection,

   risks are to the regulator only.

   One thing we DO know is that automotive wound-field alternators

   do live happily in airplanes running 10,000+ RPM. This is the

   next-to-zero-risk approach.



   How much time are you willing to invest in the experiment

   to validate the 4.5# decision?



   Bob . . .

echristley(at)nc.rr.com
Guest

Posted: Sat Aug 16, 2008 8:06 am Post subject: John Deere dynamo

Robert L. Nuckolls, III wrote:

 	  Quote: 	
		  

    This critter is good for about 12-15A when turned

    fast enough and assuming that the companion regulator-

    rectifier isn't over-stressed by the higher input

    operating voltage.  I've prayed a bit over the

    schematics for an exemplar device . . .



 http://aeroelectric.com/Pictures/Schematics/3-Phase_PM_Rectifier_Regulator.gif 

Bob, this is a switching type regulator, isn't it?
	




I'm using a PM generator, and I'm unsure about the regulator that came 

with the kit. From what I can gather, it appears that Harley-Davidson is 

still using linear regulators.  I'd rather avoid that extra heat and 

wear if possible.



-- 



http://www.ernest.isa-geek.org

nuckolls.bob(at)cox.net
Guest

Posted: Sat Aug 16, 2008 12:17 pm Post subject: John Deere dynamo

At 12:05 PM 8/16/2008 -0400, you wrote:

 	  Quote: 	

<echristley(at)nc.rr.com>

Robert L. Nuckolls, III wrote:

>

>    This critter is good for about 12-15A when turned

>    fast enough and assuming that the companion regulator-

>    rectifier isn't over-stressed by the higher input

>    operating voltage.  I've prayed a bit over the

>    schematics for an exemplar device . . .

>

>http://aeroelectric.com/Pictures/Schematics/3-Phase_PM_Rectifier_Regulator.gif 

>

Bob, this is a switching type regulator, isn't it?

   Uhhh  . . . I guess you could call it that. It's not the

   legacy switch-mode regulator where duty-cycle controlled

   switches, inductors, capacitors and catch diodes do high

   efficiency voltage shifting.

   These are simple series switches that either reduce

   throughput by delaying the time between waveform zero-

   crossing and the firing of an SCR at the optimum later

   time to throttle throughput. It's exceedingly simple

   and adequate to the task if not terribly efficient.

   These regulators use single junction diodes AND

   4-layer SCRs. Total voltage drop in the on-state,

   especially in a 14v system chews up quite a chunk

   of system efficiency. They're better at the higher

   voltages so a 28v version is not quite so bad.

   I've often thought about rewinding one of these

   things for say 60-80 volts of 3-phase AC output

   that would then be rectified and conditioned by

   a REAL switch-mode supply. But pencilling the numbers

   wasn't a BIG improvement in efficiency and a BIG

   increase in parts-count.

 	  Quote: 	
		  I'm using a PM generator, and I'm unsure about the regulator that came 

with the kit. From what I can gather, it appears that Harley-Davidson is 

still using linear regulators.  I'd rather avoid that extra heat and wear 

if possible.

   I doubt that any one does a true linear regulator

   at these power levels. They HAVE moved from the

   pure shunt (waste what you don't need) type of

   regulator common to 1970 designs) to a series

   configuration that does not waste as much energy

   overall. The only heat issue is in keeping the

   regulator itself cool . . . and as you can see

   in pictures of the various products offered, the

   BIG guys are in cast housings with fins. There

   are no significant wear advantages between the

   various offerings as long as things stay cool

   enough.

   Bob . . .

        ----------------------------------------)

        ( . . .  a long habit of not thinking   )

        ( a thing wrong, gives it a superficial )

        ( appearance of being right . . .       )

        (                                       )

        (                  -Thomas Paine 1776-  )

        ----------------------------------------

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