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John Deere PM alternator regulator

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klehman(at)albedo.net
Guest

Posted: Sat Sep 09, 2006 12:31 pm Post subject: John Deere PM alternator regulator

I can now say for certain that the AM101406 regulator will not come to 

life with a totally dead battery.  Since I was at homebase, without 

power for a charger, and like to experiment, I attempted to charge the 

dead battery by closing the Z-14 cross feed contactor and charging the 

dead battery with the good alternator for a few minutes until the PM 

alternator came to life. I wouldn't recommend that and in this case it 

seems to have caused the regulator to fail full on. I don't really know 

why it failed as the rpm was modest (well below the max output 

capability of the 20 amp PM alternator) and it is not particularly 

uncommon to have dead batteries on the small tractors that these are 

original equipment on. Further the regulator is on the cool side of the 

firewall.



My best theory is that  the totally dead small AGM battery allowed the 

output to overvoltage some component in the regulator. I do not have a 

battery contactor so I felt that there was no need for a large 

electrolytic capacitor on the  output since the battery would never be 

disconnected. The oem application doesn't have a capacitor. AFAIK 

totally dead batteries can be reluctant to take a charge at first so 

maybe it wasn't absorbing enough current initially to dampen the output 

pulses?? Again I wouldn't  have expected that to fail a regulator 

designed to work with up to 200vac open circuit voltage from the alternator.



The OVM worked perfectly. It is wired to interupt the line from the 

alternator to the regulator. In further experimenting, the little 40 amp 

relay does not seem to have suffered noticeably from a few 20 amp 

disconnects.  I also learned that a single 9ah battery will start the 

subaru rather nicely so all in all I have obtained some value for the 

cost of my experimentation    I guess I also obtained some value from 

the OVM modules 



As a shot in the dark I am thinking of putting a capacitor on the output 

of the regulator. That would leave the capacitor permanently wired 

across the battery through the b-lead circuit breaker.  I don't think 

transorbs there would help. Any other suggestions? The obvious one is to 

charge the battery first but that is not always convenient as sooner or 

later I will likely run a battery dead again in some out of the way place.



I do not have a charging indicator lamp wired to the regulator but I am 

assuming that is irrelevant.



Ken

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dcarter11(at)sbcglobal.ne
Guest

Posted: Sat Sep 09, 2006 8:37 pm Post subject: John Deere PM alternator regulator

Ken,



For my info what is your last name?  I thought at first you would be Ken 

Powell who I have shared info with about Deere PM alternators, but the 

e-mail address is different.



In any case, could you will in some of the "scenario":



1. The battery was dead, and you charged the battery from a non-PM 

alternator after starting the engine.

. . . So, you have two batteries, 1 was dead, 1 was OK enough to start 

engine.

. . . You have two alternators (a PM and a "standard" - not a bad idea when 

building experience with an unproven application like a Deere on an 

airplane)

. . . . . and used the non-PM to attempt to charge the dead battery.



2.  Was the PM alternator isolated from the good battery so it or its Deere 

voltage regulator lacked some needed "excitation"?



Looks like we need a "functional test" (experiment) to determine 

characteristics of a Deere PM alternator and VR to see how it performs in 

our application:  We should find out "on a bench" that the Deere system 

won't work with a dead battery.



Actually, there are two dead battery cases that come to mind:

1.  Before flight, battery is dead.  Don't fly with dead battery - so this 

is a ground maintenance scenario.

2.  During flight, battery dies and I want to continue flight with my PM 

alternator to some suitable landing spot, either "soon" or "procede to final 

destination" (whatever my risk analysis and good judgement and experience 

and prior planning for this scenario may indicate is "safe enough")

. . . I plan to have two batteries, so 2. would have to include loss of BOTH 

batteries or some portion of the electrical circuit.



Does you experience in this case you are reporting indicate that the PM 

alternator system might stop putting out voltage and current if battery 

power is lost?



David Carter



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klehman(at)albedo.net
Guest

Posted: Sun Sep 10, 2006 4:38 am Post subject: John Deere PM alternator regulator

David Carter wrote:



 	  Quote: 	
		   

 <dcarter11(at)sbcglobal.net>



 Ken,



 For my info what is your last name?  I thought at first you would be 

 Ken Powell who I have shared info with about Deere PM alternators, but 

 the e-mail address is different.

 In any case, could you will in some of the "scenario":



 1. The battery was dead, and you charged the battery from a non-PM 

 alternator after starting the engine.

 . . . So, you have two batteries, 1 was dead, 1 was OK enough to start 

 engine.

 . . . You have two alternators (a PM and a "standard" - not a bad idea 

 when building experience with an unproven application like a Deere on 

 an airplane)

 . . . . . and used the non-PM to attempt to charge the dead battery.


	


Yes with a Z-14, you just clost the crossfeed contactor to  parallel the 

batteries.



 	  Quote: 	
		  

 2.  Was the PM alternator isolated from the good battery so it or its 

 Deere voltage regulator lacked some needed "excitation"?


	


Yes. For experimentation I put a few short charges into the completely 

dead battery and kept trying the pm alternator. The pm alternator would 

not come alive until the dead battery was pretty much up to 12 volts. 

This does not bother me as in normal use a dead battery would mean the 

alternator has already failed and I have low voltage warning. Mostly I'm 

mentioning it in regards to the recent thread where with other 

architectures some guys are wiring their units to be able to come alive 

with no battery voltage present.



 	  Quote: 	
		  

 Looks like we need a "functional test" (experiment) to determine 

 characteristics of a Deere PM alternator and VR to see how it performs 

 in our application:  We should find out "on a bench" that the Deere 

 system won't work with a dead battery.


	


I believe I have confirmed that. What does bother me is that the VR 

failed while I was conducting the above scenario. I would like to 

prevent that in the future as sooner or later I will miss a switch and 

run the battery dead again. At home base I will charge it first but this 

aircraft will fly to a number of remote locations. At least the VR 

failed on rather than off. It seemed to run fine paralleled with the 

crossfeed closed as long as I had the total system loads above the pm's 

20 amp output.



 	  Quote: 	
		  

 Actually, there are two dead battery cases that come to mind:

 1.  Before flight, battery is dead.  Don't fly with dead battery - so 

 this is a ground maintenance scenario. 


	


Yes



 	  Quote: 	
		  

 2.  During flight, battery dies and I want to continue flight with my 

 PM alternator to some suitable landing spot, either "soon" or "procede 

 to final destination" (whatever my risk analysis and good judgement 

 and experience and prior planning for this scenario may indicate is 

 "safe enough")

 . 


	


This does not concern me at all. Loss of either of my systems is not a 

show stopper for me and I don't believe it is a significant risk in any 

event.



 	  Quote: 	
		   . . I plan to have two batteries, so 2. would have to include loss of 

 BOTH batteries or some portion of the electrical circuit.



 Does you experience in this case you are reporting indicate that the 

 PM alternator system might stop putting out voltage and current if 

 battery power is lost? 


	


Don't know. I donlt think one shorted cell would not stop it. I have 

seen several flooded batteries open circuit in operation though and I 

never even noticed til shutdown and subsequent restart attempt. I am not 

confident that would happen with this regulator though because I don't 

really know why it failed in this case. I am certain that it failed 

before it was heavily loaded and before it had a chance to heat up 

significantly. I suspect that it won't tolerate this scenario. Note that 

my OVM cut off power into the VR but the VR still failed.

Ken Lehman

(haven't put my last name on a list in years other than in my address 

but this list is pretty large now I guess)



[quote]



 David Carter



 ---

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N6030X(at)DaveMorris.com
Guest

Posted: Sun Sep 10, 2006 5:28 am Post subject: John Deere PM alternator regulator

Many in the Corvair group (www.FlyCorvair.com) are using this same 

John Deere generator/VR combo.  You might take up the question there 

and find out what people have witnessed.  The guy who's probably 

flown more hours with that combo than anybody is Gus Warren down at 

William Wynne's hangar in Florida.



Dave Morris



At 07:38 AM 9/10/2006, you wrote:

 	  Quote: 	
		  



David Carter wrote:



>

><dcarter11(at)sbcglobal.net>

>

>Ken,

>

>For my info what is your last name?  I thought at first you would 

>be Ken Powell who I have shared info with about Deere PM 

>alternators, but the e-mail address is different.

>In any case, could you will in some of the "scenario":

>

>1. The battery was dead, and you charged the battery from a non-PM 

>alternator after starting the engine.

>. . . So, you have two batteries, 1 was dead, 1 was OK enough to 

>start engine.

>. . . You have two alternators (a PM and a "standard" - not a bad 

>idea when building experience with an unproven application like a 

>Deere on an airplane)

>. . . . . and used the non-PM to attempt to charge the dead battery.

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klehman(at)albedo.net
Guest

Posted: Wed Sep 13, 2006 6:21 pm Post subject: John Deere PM alternator regulator

I can add one more interesting tidbit to this thread.  Disconnecting the 

Battery wire from the failed regulator does NOT stop the overvoltage. 

I'm told it does stop the alternator output with a good regulator but it 

does not do that on this failed unit.



Sounds similar to the automotive IR alternator where we also can not 

guarantee that disconnecting the IGN wire will stop the alternator 

output if the VR has already failed and is causing an overvoltage.



Ken



Dave N6030X wrote:



 	  Quote: 	
		   

 <N6030X(at)DaveMorris.com>



 Many in the Corvair group (www.FlyCorvair.com) are using this same 

 John Deere generator/VR combo.  You might take up the question there 

 and find out what people have witnessed.  The guy who's probably flown 

 more hours with that combo than anybody is Gus Warren down at William 

 Wynne's hangar in Florida.



 Dave Morris

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