Matronics Email Lists :: View topic - Modifing an ND alternator regulator

Matronics Email Lists
Web Forum Interface to the Matronics Email Lists

Get Email Distribution Too! FAQ Search Memberlist Usergroups Register

Profile Log in to check your private messages Log in

Modifing an ND alternator regulator

Matronics Email Lists Forum Index -> AeroElectric-List

View previous topic :: View next topic

Author Message

paulm(at)olypen.com
Guest

Posted: Sat Jul 01, 2006 9:35 pm Post subject: Modifing an ND alternator regulator

Brian,

  

 The ND generic alternator uses a  different way of powering the regulator. The 3 diodes you mention are not used  (missing from the design) in the ND brand. The regulator gets its power directly  from the "B" lead and the connection is part of a bolted stack of connections  that are not easy to isolate for the builder. 

  

 The MI brand, also popular, as its  small and light (for the 50+amp current output) has the 3 diodes you mention and  a simple snip of an internal link does the job you suggest (also covered in  the Contact! article {Years old BTW}).

  

 Its very easy to modify the regulator  to make the alternator 100% external regulation but the resulting modification  requires a ground switching external regulator, not the more common positive  switching regulator (LR3 for example). Transpo and most other regulator  manufacturers have both types and have proven quite reliable in the trucking  industry.

  

 It does not seem easy to keep the  internal regulator usable because of the way the "B" lead is connected  mechanically. Possible but only with some mechanical mods which I would not  recommend for most builders. Low cost external regulators are a much better way  to go; If one is worried about the concerns, by many, about some failure modes  of internal regulators.

  

 The above modification takes around one  hour from start of regulator removal to completion and reassembly. No case  splitting etc is required. Its very simple to do. The end bells. bearings,  and armature are not disturbed. A really neat design for simple repairs etc.  This approach does have one fault mode of possible concern as the ground switch  in the regulator can short. This is simple to provide for with a relay as it  only switches the field not the HI current "B" lead.

  

 This mod is 100% contained within the  bolt on regulator module so getting a replacement alternator that fits is  much simpler as all you need do is exchange the regulator with your converted  one which is a 10 min task.

  

 I am willing (if there is enough  interest) to make a brand new PDF showing the details with new pictures etc. It  would take a couple of weeks to do as this coming week is Arlington air show  where I am a long time volunteer.

  

 For the record I know of NO B&C  alternator failure. I have in my possession a failed LR3 regulator that burned  up internally (part(s) charred) and did not pop the CB!. I have not heard of any  other LR3 failures so that pricey system is very reliable in my opinion. The  above (my) suggested approach is around $100 (and up) for a brand new ND  alternator Lester #14684, one hour of your time, and a $25 ground switching regulator (no I do not  have a part number handy). I am not convinced there is any measurable  reliability difference for the extra $600+. The 14684 is rated for 18,000 rpm by  the manufacturer.

  

 On the other hand I know of NO Brand  New ND alternator (with internal regulator) that failed except for quite a few  where there was a crowbar module and a common contactor in the "B" lead. That  setup with (out other/different parts etc) has both a theoretical analysis and  demonstrated high chance of failing a good alternator from false or intentional  tripping. The typical contactor is not designed to break the electrical load of  the alternator and the use of a diode across the contactor makes it 5-10  times more likely the result will burn out the alternator that  otherwise was good. Also lots of used repaired alternators failing.  Repaired is what is done, rebuilt is misleading.

  

 Thus, if you throw out the rebuilt  failures and the crow bar/contactor failures, I know of NO failures of the Stock  new ND alternator.

  

 The above for data demanders (I am  one also)

  

  Paul

  

 PS I only post when my name comes up  and I feel its important to comment.



  

 ---

- The Matronics AeroElectric-List Email Forum -

Use the List Feature Navigator to browse the many List utilities available such as the Email Subscriptions page, Archive Search & Download, 7-Day Browse, Chat, FAQ, Photoshare, and much more:

http://www.matronics.com/Navigator?AeroElectric-List

brian

Joined: 02 Jan 2006
Posts: 643
Location: Sacramento, California, USA

Posted: Sun Jul 02, 2006 5:58 am Post subject: Modifing an ND alternator regulator

On Jul 2, 2006, at 1:34 AM, Paul Messinger wrote:



 	  Quote: 	
		   Brian,



 The ND generic alternator uses a different way of powering the  

 regulator. The 3 diodes you mention are not used (missing from the  

 design) in the ND brand. The regulator gets its power directly from  

 the "B" lead and the connection is part of a bolted stack of  

 connections that are not easy to isolate for the builder.


	


That is odd. Without the diodes to provide isolation the battery  

would be providing power to the regulator even when the engine isn't  

running. Remember, most automobiles have the alternator connected to  

the battery all the time. This would drain the battery. I would like  

to see how they prevent the alternator from killing the battery.



 	  Quote: 	
		   The MI brand, also popular, as its small and light (for the 50+amp  

 current output) has the 3 diodes you mention and a simple snip of  

 an internal link does the job you suggest (also covered in the  

 Contact! article {Years old BTW}).


	


I understand. Sounds like you wrote a good article.



 	  Quote: 	
		   Its very easy to modify the regulator to make the alternator 100%  

 external regulation but the resulting modification requires a  

 ground switching external regulator, not the more common positive  

 switching regulator (LR3 for example). Transpo and most other  

 regulator manufacturers have both types and have proven quite  

 reliable in the trucking industry.


	


You might be able to break the path from the B-lead to the field and  

then have access to both field terminals. Then you can do what you  

want with it. And I agree, I prefer an externally regulated  

alternator myself.



 	  Quote: 	
		   It does not seem easy to keep the internal regulator usable because  

 of the way the "B" lead is connected mechanically. Possible but  

 only with some mechanical mods which I would not recommend for most  

 builders. Low cost external regulators are a much better way to go;  

 If one is worried about the concerns, by many, about some failure  

 modes of internal regulators.


	


Never having seen the inside of a ND alternator I knew I was going  

out on a bit of a limb. But it might not be that hard. Heck, if you  

have people building a whole airframe you have to assume they have  

learned how to properly drill a hole and install a bolt in it. 



 	  Quote: 	
		  

 The above modification takes around one hour from start of  

 regulator removal to completion and reassembly. No case splitting  

 etc is required. Its very simple to do. The end bells. bearings,  

 and armature are not disturbed. A really neat design for simple  

 repairs etc. This approach does have one fault mode of possible  

 concern as the ground switch in the regulator can short. This is  

 simple to provide for with a relay as it only switches the field  

 not the HI current "B" lead.



 This mod is 100% contained within the bolt on regulator module so  

 getting a replacement alternator that fits is much simpler as all  

 you need do is exchange the regulator with your converted one which  

 is a 10 min task.



 I am willing (if there is enough interest) to make a brand new PDF  

 showing the details with new pictures etc. It would take a couple  

 of weeks to do as this coming week is Arlington air show where I am  

 a long time volunteer.


	


I would certainly like to see it.



Brian Lloyd                         361 Catterline Way

brianl at lloyd dot com             Folsom, CA 95630

+1.916.367.2131 (voice)             +1.270.912.0788 (fax)



"Five percent of the people think.

  Ten percent of the people think they think.

  Eighty-five percent of the people would rather die than think."

        ---Thomas A. Edison





Brian Lloyd                         361 Catterline Way

brian-yak AT lloyd DOT com          Folsom, CA 95630

+1.916.367.2131 (voice)             +1.270.912.0788 (fax)



I fly because it releases my mind from the tyranny of petty things . . .

— Antoine de Saint-Exupéry

- The Matronics AeroElectric-List Email Forum -

Use the List Feature Navigator to browse the many List utilities available such as the Email Subscriptions page, Archive Search & Download, 7-Day Browse, Chat, FAQ, Photoshare, and much more:

http://www.matronics.com/Navigator?AeroElectric-List

_________________
Brian Lloyd
brian-yak at lloyd dot com
+1.916.367.2131 (voice) +1.270.912.0788 (fax)

I fly because it releases my mind from the tyranny of petty things . . .
- Antoine de Saint-Exupery

paulm(at)olypen.com
Guest

Posted: Sun Jul 02, 2006 7:21 am Post subject: Modifing an ND alternator regulator

The isolation is internal to the regulator to prevent high current drain 

when the battery is connected and the engine is off. The "IGN" lead 

controlls the "B" lead power to the regulator. There is some current drain 

which requires an auto to be started every 10-20 days to prevent large 

battery discharging which is not an issue in an aircraft. Its worth noting 

the ND regulator design for this ND series is 30 years old. The amount of 

standby drain varies with the specific regulator but I have seen as much as 

90 ma in an auto.



The start of this original failure thread had a comment that the IGN lead 

did not turn off the alternator. This tells me the "rebuilt alternator had a 

already failed regulator as a good ND regulator will turn on and off the 

power when running using the IGN lead.



I guess this is a clear warning about rebuilt alternators and associated 

quality control 



As for seperating the field, nothing is impossible but its not something I 

would want the average person to do and I see no point to having an internal 

regulator with total external control. I have looked into that and felt it 

was not for most people to try. Its hard to describe but the ND mechanical 

wiring is different from most alternators and that makes you idea harder to 

do.



Go one way or the other(internal or external). There are 100% safe ways of 

disconnecting the "B" lead but a just a common contactor is not a safe way. 

The only contactor available at a "reasonable" price rated to open that 

circuit is the kilovac. Electrical parts (External to the common contactor) 

can be added to make the contactor safe but that is a different issue not 

included here.



Paul



---

- The Matronics AeroElectric-List Email Forum -

Use the List Feature Navigator to browse the many List utilities available such as the Email Subscriptions page, Archive Search & Download, 7-Day Browse, Chat, FAQ, Photoshare, and much more:

http://www.matronics.com/Navigator?AeroElectric-List

brian

Joined: 02 Jan 2006
Posts: 643
Location: Sacramento, California, USA

Posted: Sun Jul 02, 2006 5:49 pm Post subject: Modifing an ND alternator regulator

On Jul 2, 2006, at 11:21 AM, Paul Messinger wrote:



 	  Quote: 	
		   

 <paulm(at)olypen.com>



 The isolation is internal to the regulator to prevent high current  

 drain when the battery is connected and the engine is off. The  

 "IGN" lead controlls the "B" lead power to the regulator. There is  

 some current drain which requires an auto to be started every 10-20  

 days to prevent large battery discharging which is not an issue in  

 an aircraft. Its worth noting the ND regulator design for this ND  

 series is 30 years old. The amount of standby drain varies with the  

 specific regulator but I have seen as much as 90 ma in an auto.



 The start of this original failure thread had a comment that the  

 IGN lead did not turn off the alternator. This tells me the  

 "rebuilt alternator had a already failed regulator as a good ND  

 regulator will turn on and off the power when running using the IGN  

 lead.


	


I guess I read this a different way. If the regulator has power  

applied and there are enough electrons flowing to allow the IGN lead  

to control the behavior of the regulator, the regulator is "on" to  

some extent. Kind of like most consume electronics that are drawing  

power and doing things with their microprocessors even when they are  

"off". Just because you turn the switch to "off" doesn't mean it  

isn't drawing power and doing something.



 	  Quote: 	
		  

 I guess this is a clear warning about rebuilt alternators and  

 associated quality control 



 As for seperating the field, nothing is impossible but its not  

 something I would want the average person to do and I see no point  

 to having an internal regulator with total external control. I have  

 looked into that and felt it was not for most people to try. Its  

 hard to describe but the ND mechanical wiring is different from  

 most alternators and that makes you idea harder to do.


	


That is certainly a possibility. I have no experience with the ND  

alternator.

 	  Quote: 	
		  

 Go one way or the other(internal or external). There are 100% safe  

 ways of disconnecting the "B" lead but a just a common contactor is  

 not a safe way. The only contactor available at a "reasonable"  

 price rated to open that circuit is the kilovac. Electrical parts  

 (External to the common contactor) can be added to make the  

 contactor safe but that is a different issue not included here.


	


And that issue has already been beaten to death. Having the pass/ 

switch transistor fail shorted will cause any IR alternator to turn  

on hard with no way to turn it off. It seemed to me if we could  

control the field excitation externally we could truly turn off the  

alternator.



I will now shut up about this. I plan to get a B&C alternator as B&C  

already has the mounting and adaptor plates for the Russian radial  

engine. I don't plan to use an ND alternator.



Brian Lloyd                         361 Catterline Way

brian-yak AT lloyd DOT com          Folsom, CA 95630

+1.916.367.2131 (voice)             +1.270.912.0788 (fax)



I fly because it releases my mind from the tyranny of petty things . . .

— Antoine de Saint-Exupéry

- The Matronics AeroElectric-List Email Forum -

Use the List Feature Navigator to browse the many List utilities available such as the Email Subscriptions page, Archive Search & Download, 7-Day Browse, Chat, FAQ, Photoshare, and much more:

http://www.matronics.com/Navigator?AeroElectric-List

paulm(at)olypen.com
Guest

Posted: Sun Jul 02, 2006 7:42 pm Post subject: Modifing an ND alternator regulator

---

- The Matronics AeroElectric-List Email Forum -

Use the List Feature Navigator to browse the many List utilities available such as the Email Subscriptions page, Archive Search & Download, 7-Day Browse, Chat, FAQ, Photoshare, and much more:

http://www.matronics.com/Navigator?AeroElectric-List

Display posts from previous:

	Matronics Email Lists Forum Index -> AeroElectric-List	All times are GMT - 8 Hours
Page 1 of 1

Jump to:

You cannot post new topics in this forum
You cannot reply to topics in this forum
You cannot edit your posts in this forum
You cannot delete your posts in this forum
You cannot vote in polls in this forum
You cannot attach files in this forum
You can download files in this forum