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mstewart(at)iss.net
Guest

Posted: Wed Jun 28, 2006 3:47 am Post subject: Alternator failure. Info provided

After 250 hours my 14684 ND alternator finally gave way. Of course I was a thousand miles from home when it did. Went running around the big city of Denver for hours getting a replacement. Best I could come up with was a 14870 for a 1988 Chevy Sprint. Most auto part shops did not even show the 14684 number. Although the mount ears on the 14870 were in a different location, as was the bat post, I was able to finagle washers and new bolts to get her back up and flying for the ride home.   

The 14684 alternator I bought from Vans for my RV-8 behaves differently than the new 14870 Im now running. The 14684, once the field was excited, would keep charging as long as the pulley was turning. You could turn off the field and it would keep charging. The new 14870 will shut off when the field is off. I have the OV protection on a contactor. Also sometime during the alternator failure, my Lightspeed ignition blew its 3 amp fuse. Klaus said I should have a 5 amp in there anyway.   

   

I took the 14684 to an alternator shop for repair when I got home and he said it looked like the stator was cooked, but he could not get any parts for it. So its now a door stop.  

   

Information for the group if you happen to be on the road and cant find the 14684 locally. You can get the 14870 to work on your RV and a lyco mount with new bolts and washers to shim for alignment.   

Best  

Mike Stewart

mstewart(at)iss.net
Guest

Posted: Wed Jun 28, 2006 6:45 am Post subject: Alternator failure. Info provided

Yes the new alternator 14870 is a 55amp alternator. So was the old one.  

It’s a ND bought from Autozone in stock, lifetime warrantee whos receipt is now permanently in the plane.   

The ears were oriented correctly, it was the ear spacing that was off. I run at 12 amps normally.   

Damn all these alternator problems anyway. In 1800 hours of RV flying in 2 planes, this is my 5th alternator. ARGH!  

A friend recommended I put the 4” pulley on. Im very tight in the cowl with my 6cyl installation. Not sure if I could get it in there.  

   

Mike  

   

   

         

  

From: Charlie Kuss [mailto:chaztuna(at)adelphia.net] 

 Sent: Wednesday, June 28, 2006 9:46 AM

 To: Stewart, Michael (ISS Atlanta)

 Subject: Re: AeroElectric-List: Alternator failure. Info provided  

  

   

Mike

  Thanks for the report. Could you tell me what brand or what auto parts store you found your alternator at? Are these the 35 amp or 60 amp models? FYI, you can easily "clock" the two case housing halves to get the ears oriented like your original alternator. Many of the various alternator part numbers differ only in how the case halve are oriented to each other, as required by the auto manufacturer's requirements.

  I'm a firm believer in using parts which are automotive based and readily available. Your 4 hour ordeal is proof of the wisdom of this. I like the starter shown below. It's off of a Toyota pick up truck. See

 

 http://cgi.ebay.com/ebaymotors/Airboat-Starter-forTextron-Lycoming-Engines-149tfw-NR_W0QQcmdZViewItemQQcategoryZ26439QQihZ002QQitemZ4580254772QQtcZphoto 

 

 FYI  for maximum alternator life, your nominal current draw from the alternator shouldn't exceed 60% of it's rated output. Forcing a 35 amp unit to produce 25 amps for long periods is a sure route to short life. The rectifier diodes are heat sensitive. These items are the weak link in most alternators. Cheapo rebuilds use cheapo diodes. Real ND, NAPA or other name brand diodes go a long way to ensuring long life.

 

 Charlie Kuss

 

 

 

   

After 250 hours my 14684 ND alternator finally gave way. Of course I was a thousand miles from home when it did. Went running around the big city of Denver for hours getting a replacement. Best I could come up with was a 14870 for a 1988 Chevy Sprint. Most auto part shops did not even show the 14684 number. Although the mount ears on the 14870 were in a different location, as was the bat post, I was able to finagle washers and new bolts to get her back up and flying for the ride home. 

 The 14684 alternator I bought from Vans for my RV-8 behaves differently than the new 14870 Im now running. The 14684, once the field was excited, would keep charging as long as the pulley was turning. You could turn off the field and it would keep charging. The new 14870 will shut off when the field is off. I have the OV protection on a contactor. Also sometime during the alternator failure, my Lightspeed ignition blew its 3 amp fuse. Klaus said I should have a 5 amp in there anyway. 

  

 I took the 14684 to an alternator shop for repair when I got home and he said it looked like the stator was cooked, but he could not get any parts for it. So its now a door stop.

  

 Information for the group if you happen to be on the road and cant find the 14684 locally. You can get the 14870 to work on your RV and a lyco mount with new bolts and washers to shim for alignment. 

 Best

 Mike Stewart

frank.hinde(at)hp.com
Guest

Posted: Wed Jun 28, 2006 7:40 am Post subject: Alternator failure. Info provided

Uh-oh...I have an Autozone 60A (Toyota Camry) alt on my 7a  (not flying yet)...Hope I did'nr make a bad decision here.

  

 BTW...Autozone have your name in their computer so they can  find you by your phone number if you show up with a dead part a long ways from  home.

  

 Frank

  

 Do not archive



   From:  owner-aeroelectric-list-server(at)matronics.com  [mailto:owner-aeroelectric-list-server(at)matronics.com] On Behalf Of  Stewart, Michael (ISS Atlanta)

Sent: Wednesday, June 28, 2006 7:42  AM

To: aeroelectric-list(at)matronics.com

Subject: RE:  Alternator failure. Info provided

 

  

Yes the new alternator  14870 is a 55amp alternator. So was the old one. 

It’s a ND bought from  Autozone in stock, lifetime warrantee whos receipt is now permanently in the  plane.  

The ears were oriented  correctly, it was the ear spacing that was off. I run at 12 amps normally.   

Damn all these  alternator problems anyway. In 1800 hours of RV flying in 2 planes, this is my  5th alternator. ARGH! 

A friend recommended I  put the 4” pulley on. Im very tight in the cowl with my 6cyl installation. Not  sure if I could get it in there. 

  

Mike 

  

  

     

 

From: Charlie  Kuss [mailto:chaztuna(at)adelphia.net] 

Sent: Wednesday, June 28, 2006 9:46  AM

To: Stewart, Michael (ISS  Atlanta)

Subject: Re: Alternator  failure. Info provided

 

  

Mike

 Thanks for the report. Could you tell me  what brand or what auto parts store you found your alternator at? Are these the  35 amp or 60 amp models? FYI, you can easily "clock" the two case housing halves  to get the ears oriented like your original alternator. Many of the various  alternator part numbers differ only in how the case halve are oriented to each  other, as required by the auto manufacturer's requirements.

 I'm a firm  believer in using parts which are automotive based and readily available. Your 4  hour ordeal is proof of the wisdom of this. I like the starter shown below. It's  off of a Toyota  pick up truck. See



http://cgi.ebay.com/ebaymotors/Airboat-Starter-forTextron-Lycoming-Engines-149tfw-NR_W0QQcmdZViewItemQQcategoryZ26439QQihZ002QQitemZ4580254772QQtcZphoto  



FYI  for maximum alternator life, your nominal current draw from  the alternator shouldn't exceed 60% of it's rated output. Forcing a 35 amp unit  to produce 25 amps for long periods is a sure route to short life. The rectifier  diodes are heat sensitive. These items are the weak link in most alternators.  Cheapo rebuilds use cheapo diodes. Real ND, NAPA or other name brand diodes go a long way  to ensuring long life.



Charlie  Kuss



 

After 250 hours my 14684 ND alternator finally gave way.  Of course I was a thousand miles from home when it did. Went running around the  big city of Denver for hours getting a replacement. Best I  could come up with was a 14870 for a 1988 Chevy Sprint. Most auto part shops did  not even show the 14684 number. Although the mount ears on the 14870 were in a  different location, as was the bat post, I was able to finagle washers and new  bolts to get her back up and flying for the ride home. 

The 14684 alternator  I bought from Vans for my RV-8 behaves differently than the new 14870 Im now  running. The 14684, once the field was excited, would keep charging as long as  the pulley was turning. You could turn off the field and it would keep charging.  The new 14870 will shut off when the field is off. I have the OV protection on a  contactor. Also sometime during the alternator failure, my Lightspeed ignition  blew its 3 amp fuse. Klaus said I should have a 5 amp in there anyway.  

 

I took the 14684 to an alternator shop for repair when I got home  and he said it looked like the stator was cooked, but he could not get any parts  for it. So its now a door stop.

 

Information for the group if you  happen to be on the road and cant find the 14684 locally. You can get the 14870  to work on your RV and a lyco mount with new bolts and washers to shim for  alignment. 

Best

Mike  Stewart

nuckollsr(at)cox.net
Guest

Posted: Wed Jun 28, 2006 7:50 am Post subject: Alternator failure. Info provided

At 10:42 AM 6/28/2006 -0400, you wrote:



 	  Quote: 	
		  Yes the new alternator 14870 is a 55amp alternator. So was the old one.



It s a ND bought from Autozone in stock, lifetime warrantee whos receipt 

is now permanently in the plane.



The ears were oriented correctly, it was the ear spacing that was off. I 

run at 12 amps normally.



Damn all these alternator problems anyway. In 1800 hours of RV flying in 2 

planes, this is my 5th alternator. ARGH!



A friend recommended I put the 4 pulley on. Im very tight in the cowl with 

my 6cyl installation. Not sure if I could get it in there.


	


   Why the 4" pulley? Running an alternator "fast" bears

   on mechanical wear rate issues. Aside from B&C's

   conclusion that "fast" alternators were at-risk

   for vibration induced bearing failures (for which

   they elected to carefully balance new alternators)

   there are no issues I'm aware of that warrant

   slowing the alternator down with a larger pulley.



   Alternator speed does not bear on electrical failures

   unless they are aggravated by heating where turning

   faster moves more air.



   Bob . . .

Mark Phillips in TN

Joined: 10 Jan 2006
Posts: 431
Location: Columbia, TN

Posted: Wed Jun 28, 2006 7:55 am Post subject: Alternator failure. Info provided

In a message dated 6/28/06 9:54:14 AM Central Daylight Time, mstewart(at)iss.net writes:

 

  	  Quote: 	
		  5th alternator. ARGH! 	


 

 MIke- any B&Cs in this gang of five?

 

 Mark do not archive

_________________
From The PossumWorks...

mstewart(at)iss.net
Guest

Posted: Wed Jun 28, 2006 9:14 am Post subject: Alternator failure. Info provided

No.   

First 3 were the old vans 35 amp alt. . 79 Honda Civic was the application as I recall.  

Next 2 were the 14684 ND ones.  

Mike  

   

         

  

From: owner-aeroelectric-list-server(at)matronics.com [mailto:owner-aeroelectric-list-server(at)matronics.com] On Behalf Of Fiveonepw(at)aol.com

 Sent: Wednesday, June 28, 2006 11:53 AM

 To: aeroelectric-list(at)matronics.com

 Subject: Re: AeroElectric-List: Alternator failure. Info provided  

  

   

In a message dated 6/28/06 9:54:14 AM Central Daylight Time, mstewart(at)iss.net writes:

 

 

   

5th alternator. ARGH!  



 

 MIke- any B&Cs in this gang of five?

 

 Mark do not archive

ainut(at)hiwaay.net
Guest

Posted: Wed Jun 28, 2006 10:16 am Post subject: Alternator failure. Info provided

Over the years, I've have terrible luck with Autozone electrical items, 

alternators, starters, and etc.  I won't put them on my cars now. 

Autozone does make good on the warranty but I hate having to replace 

things multiple times.  On a plane, the risk is high.  Get one from a 

reputable jobber.  Cost is about the same.



David M.

Hinde, Frank George (Corvallis) wrote:



 	  Quote: 	
		   Uh-oh...I have an Autozone 60A (Toyota Camry) alt on my 7a (not flying 

 yet)...Hope I did'nr make a bad decision here.

  

 BTW...Autozone have your name in their computer so they can find you by 

 your phone number if you show up with a dead part a long ways from home.

  

 Frank

brinker(at)cox-internet.c
Guest

Posted: Wed Jun 28, 2006 11:05 am Post subject: Alternator failure. Info provided

AMEN

---

Dick Sipp

Joined: 11 Jan 2006
Posts: 215
Location: Hope, MI

Posted: Wed Jun 28, 2006 7:25 pm Post subject: Alternator failure. Info provided

Mike:

  

 Have a look at the new Plane Power alternators. http://www.plane-power.com/

  

 I have one for the 10, nice piece of work and dirt simply to  wire as well as a bolt on for the 540. Integrated regulator and overvoltage  protection.

  

 Frogman

 [quote]   ---

brian

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

Posted: Wed Jun 28, 2006 7:28 pm Post subject: Alternator failure. Info provided

On Jun 28, 2006, at 1:06 PM, Stewart, Michael (ISS Atlanta) wrote:

 	  Quote: 	
		  

No.

First 3 were the old vans 35 amp alt. . 79 Honda Civic was the application as I recall.

Next 2 were the 14684 ND ones.

	
So, in terms of time and trouble, do you think that maybe the B&C alternator and controller would be cheaper in the long run?



 Brian Lloyd                         361 Catterline Waybrian-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

_________________
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

mstewart(at)iss.net
Guest

Posted: Thu Jun 29, 2006 3:01 am Post subject: Alternator failure. Info provided

Hmm. Good ?  

I would say its about a wash at this point. Since Im measuring against 2 planes and since I do not know what the failure rates are on the B&C.  

Lets suppose this. Lets suppose I only care about the money, which practically speaking I do.  

Lets say the the B&C should last as long as an automotive device should. If I were to assume the average car today made it 100,000 miles on an alternator (which I think is low ball since I have 2 cars with combined 300,000 miles with no alternator change). And I assume average 36mph(that’s what my car says I average). That’s 2777 hours of operation before failure. My MTBF of the 4 replacements has been 500 hours. That means I would be by buying 5.5 units to make 2777 hours of operation. (at)$118 per unit that’s $650 worth of alternators to make the 2777 hours.  

   

I really need the failure rate of the B&C now to make a comparison.  

Mike  

Do not archive  

   

         

  

From: owner-aeroelectric-list-server(at)matronics.com [mailto:owner-aeroelectric-list-server(at)matronics.com] On Behalf Of Brian Lloyd

 Sent: Wednesday, June 28, 2006 11:26 PM

 To: aeroelectric-list(at)matronics.com

 Subject: Re: AeroElectric-List: Alternator failure. Info provided  

  

   

       

On Jun 28, 2006, at 1:06 PM, Stewart, Michael (ISS Atlanta) wrote:  

  



 

     

No.  

First 3 were the old vans 35 amp alt. . 79 Honda Civic was the application as I recall.  

Next 2 were the 14684 ND ones.  

    

So, in terms of time and trouble, do you think that maybe the B&C alternator and controller would be cheaper in the long run?  

  

       

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

Hopperdhh(at)aol.com
Guest

Posted: Thu Jun 29, 2006 4:39 am Post subject: Alternator failure. Info provided

 

 I know that it is really a bummer to have alternator problems.  Almost  all of these problems are due to excessive temperature.

  

 Even a 35 amp alternator would last a lot longer (probably at least a 1000  hours) if it had a decent cooling fan.  Even one turning the wrong  direction would be a lot better than none at all.  Alternators are only  about 50 percent efficient so there is a lot of heat to get rid of.  If  you're going to count on only the blast tube, make a good shroud for the back of  the alternator.

  

 There is a lot of this information in the archives, so do not  archive.

  

 Dan Hopper

 Walton, IN

 RV-7A

brian

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

Posted: Thu Jun 29, 2006 4:54 am Post subject: Alternator failure. Info provided

On Jun 29, 2006, at 6:54 AM, Stewart, Michael (ISS Atlanta) wrote:

 	  Quote: 	
		  

Hmm. Good ?

I would say its about a wash at this point. Since Im measuring against 2 planes and since I do not know what the failure rates are on the B&C.

Lets suppose this. Lets suppose I only care about the money, which practically speaking I do.

Lets say the the B&C should last as long as an automotive device should. If I were to assume the average car today made it 100,000 miles on an alternator (which I think is low ball since I have 2 cars with combined 300,000 miles with no alternator change). And I assume average 36mph(that’s what my car says I average). That’s 2777 hours of operation before failure. My MTBF of the 4 replacements has been 500 hours. That means I would be by buying 5.5 units to make 2777 hours of operation. (at)$118 per unit that’s $650 worth of alternators to make the 2777 hours.

 

I really need the failure rate of the B&C now to make a comparison.

	


If Bill Bainbridge of B&C is to be believed, the failure rate of B&C alternators is very close to zero. When I first talked to him 7-8 years ago he claimed that the only failures had been the result of misinstallation and not from outright mechanical or electrical failure. I am sure there have been some failures but barring the customer doing something wrong with it, there have been precious few.



(And before I really stick my foot in my mouth I have to state again that my conversation with Bill on this is many years old and could very well be wrong. OTOH, I have never heard anyone complain about B&C alternators failing, only that they cost a lot of money.)



So you are at a wash on cost for the alternator but what about time and any costs incurred by being caught out somewhere else while fixing it, e.g. hotel room, taxi or car rental, restaurant, etc.? It is amazing how much the total cost of even a simple failure while on the road can add up.



There are pretty much three options for the CJ6A: the stock Russian or Chinese generator, a Delco truck alternator with a modifed shaft and adaptor plate, or a B&C alternator. I am going to go with a B&C alternator. I prefer flying to fixing and anything I can do to make the airplane more reliable is what I am going to do.

 Brian Lloyd                         361 Catterline Waybrian-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

FLYaDIVE(at)aol.com
Guest

Posted: Fri Jun 30, 2006 12:09 am Post subject: Alternator failure. Info provided

In a message dated 6/29/06 7:08:40 AM Eastern Daylight Time, mstewart(at)iss.net 

writes:



 	  Quote: 	
		   

  I really need the failure rate of the B&C now to make a comparison.

  

  Mike

====================================
	


Mike:



No, what you really need to do is stop being a bean counting manager and 

become an engineer and look at the installation.  The variable in the equation is 

NOT the alternator but the installation.  Alternators come off the assembly 

line much faster, for more planes and with much tighter tolerances than the 

planes do.  



LQQK at what is failing and why.  The problems I see and I have seen a lot, 

way more than 2 planes; is the install.  

Belts too tight

Belts too loose

Alignment of the alternator sheave to the ring gear out of whack

Wrong Belts being used - There is a difference in 'V' grove between aviation 

and automotive.

Belts not seating properly in the sheave

Alternator not mounted secure - Too much vibration

Cracked alternator mounts 

Cracked alternator tension brackets

Improper nuts & bolts used - Course thread Vs fine thread

Ridiculous stacking of washers in attempts to align alternator with ring gear

Bracket mounting bolts not torque correctly

No safety tabs on mounting bolts

No safety wire on tension bracket bolts

Safety wire installed incorrectly

OVER torquing of Field and B+ nuts

No securing method on alternator bells

Improper wire length and No service loop on alternator wires

POOR electrical grounds on the entire engine and plane



So, you can see, you have to LQQK at the entire picture and not micro manage 

one device.  



Barry

"Chop'd Liver"



QA/QA Manager

SPC

Q1

ISO 9001

Tech Sales Engineering

A&P

brian

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

Posted: Fri Jun 30, 2006 1:53 am Post subject: Alternator failure. Info provided

On Jun 30, 2006, at 3:59 AM, FLYaDIVE(at)aol.com (FLYaDIVE(at)aol.com) wrote:

 	  Quote: 	
		  --> AeroElectric-List message posted by: FLYaDIVE(at)aol.com (FLYaDIVE(at)aol.com)

In a message dated 6/29/06 7:08:40 AM Eastern Daylight Time, mstewart(at)iss.net (mstewart(at)iss.net) 

writes:

  	  Quote: 	
		  



 I really need the failure rate of the B&C now to make a comparison.

 Mike

 	
====================================

Mike:

No, what you really need to do is stop being a bean counting manager and 

become an engineer and look at the installation.  The variable in the equation is 

NOT the alternator but the installation.  Alternators come off the assembly 

line much faster, for more planes and with much tighter tolerances than the 

planes do.  

	


Your points about installation are well taken and should be heeded by all those using automotive alternators.



OTOH, what Mike said was that the stator was fried. That is what happens to an alternator operated too close to its maximum current rating. Automotive alternators, unless they are "hot rated", cannot operate anywhere near their ratings without self-destructing. This is a failure mode that occurs all the time with boats where the alternator is called upon too recharge the deep-cycle battery bank. It also happens all the time in cars that have megawatt stereo systems that draw huge amounts of power from the electrical system.



How do I know about this? Well, I became really good friends with the guy who rebuilds alternators in the Virgin Islands as I was a member of the "stator of the month" club. He was very up front about not providing a warrantee on rebuilt automotive alternators to boats with big battery banks (me) or people with big stereos in their cars. In fact, I keep a couple of stators in my spares kit. (I got so I could change a stator in about an hour including removal and reinstallation of the alternator on the engine.) I learned to be careful to monitor current output and alternator temperature to minimize failure.



The solution is simple: if you are using an automotive alternator that is not explicitly designed to operate near its rated output (hot rated), make sure your average current consumption is below 50% of the rated output of the alternator. 50A alternator? Don't design your electrical system to require more than 25A under normal, continuous operation. Intermittent loads like landing lights (unless you leave them on all the time), gear retraction systems, comm radios while transmitting, etc., are not the problem as you only use them for short periods of time. Everything else that gets turned on and left on counts.



I know that Bob recommends keeping the load on the alternator below 80% of max rating but IMHO that is not conservative enough for most automotive alternators. (Maybe it is if you have really good cooling.)



The bottom line is that, regardless of proper installation, alternators can and will self destruct if operated at their rated output. Only those that are "hot rated", i.e. have their output specified at a higher operating temperature, usually something like 100C, will be able to deliver their max output under continuous load conditions.



Oh, and hot-rated alternators cost more.



 Brian Lloyd                         361 Catterline Waybrian-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

Dale Ensing

Joined: 11 Jan 2006
Posts: 571
Location: Aero Plantation Weddington NC

Posted: Fri Jun 30, 2006 3:56 am Post subject: Alternator failure. Info provided

No securing method on alternator bells



What are alternator bells?

Dale

do not archive

_________________
Dale Ensing
RV-6A
Aero Plantation
Weddington NC

FLYaDIVE(at)aol.com
Guest

Posted: Fri Jun 30, 2006 4:24 am Post subject: Alternator failure. Info provided

In a message dated 6/30/06 5:57:51 AM Eastern Daylight Time, 

brian-yak(at)lloyd.com writes:



 	  Quote: 	
		   OTOH, what Mike said was that the stator was fried. That is what  

  happens to an alternator operated too close to its maximum current  

  rating. Automotive alternators, unless they are "hot rated", cannot  

  operate anywhere near their ratings without self-destructing. 

=====================================
	


Brian:



Someone is feeding you a bunch of bunk!  

DON'T SPREAD THE BUNK!

Hot rated ... MADE UP NONSENSE!



The same companies that make automotive alternators make aircraft 

alternators.  For example: 

1972 Ford Pickup with A/C (61 amp), as this is what the DOFF-xxxxx P/N 

crosses to in the Ford books.

DOFF-10300J AL12-F60 <- FULL P/N



The ONLY difference is the NAME PLATE.



I have taken both plane and car alternators, disconnected the regulator and 

ran them with a variable load and up to 5000 RPM.  I was able to get 107 Amps 

out of a 60 Amp Alternator.  Sure it got hot, but it did not fail.  ALL 

alternators are under rated.  They have to be if you expect them to work.  Keeping 

the LOAD at 80% of the source is just GOOD design practices.  Just because a 

wire can handle 15 Amps does not mean you run it at 15 Amps.  



What is common between plane and boats is VIBRATION.  How does a Stator fail? 

 From Vibration.  The stator is basically a SOLID unit.  It does not fail ... 

The bearings and the bell fail Because of Vibration, which causes the stator 

to go off center and usually destroying the brushes and field coil.  I have 

NEVER seen a stator fail that did not involve the bearings or bell.



As far as auto Vs plane alternators ... Give me a NEW auto type any day.  

They keep up with technology.

Don't believe it?  Look at the smaller size and higher output that we have 

today.  Other than big business using data such as MTBF to set up a warranty 

program ... YES, they reduce the quality of the components to keep operational 

times just a farts breath longer than the warranty period.  THAT is why I do not 

rebuild with OEM parts.

Barry

"Chop'd Liver"

FLYaDIVE(at)aol.com
Guest

Posted: Fri Jun 30, 2006 4:31 am Post subject: Alternator failure. Info provided

In a message dated 6/30/06 8:00:48 AM Eastern Daylight Time, 

densing(at)carolina.rr.com writes:



 	  Quote: 	
		   No securing method on alternator bells

  

  What are alternator bells?

  Dale

===============================
	


Dale:



Good question, you are the only one to ask.

Motors, alternators and even starters have bells.  They are also called END 

BELL.  They are the front and rear housing that support the bearings.  They got 

their name from the old steel motors.  When they are removed from the rest of 

the housing and struck with a hammer they RING like a bell.  Today aluminum 

has replaced the steel end bells, both for lightness and heat transfer, as well 

as production cost.



Barry

"Chop'd Liver"

Hopperdhh(at)aol.com
Guest

Posted: Fri Jun 30, 2006 5:39 am Post subject: Alternator failure. Info provided

 

 Barry,

  

 Your list of failure modes is certainly extensive and all are installation  related, and I agree with each and every one.  However, I noticed that  none of the failures that you have seen were caused by overheating.  Even  if the installation is perfect in every respect and there is not enough cooling  air brought to the alternator, it will certainly fail.  A fan is very  desirable, if not essential.  It is possible that a properly installed  blast tube could do the job, but keep in mind that it should provide as  much airflow as the fan originally did.

  

 I worked with alternators back in the sixties.  Actually I was on the  design team that built the first regulators that were put inside the  alternator.  The first application was the 1968 Pontiac Gran Prix (when the  Gran Prix was the top of the line).  I learned then that alternators can  run at 100 percent output for hours on end at underhood temperatures (125  degrees C or 257 degrees F ambient) -- with a fan.  The current output is  higher at first when the stator winding is cool, and then drops  off to the rated current as it heats up.  Increasing the  voltage causes the current to go up due to increased field current.   At that time at least, alternators were rated conservatively and a 65 amp  alternator (twice the output of a typical generator of the time) would self  limit at 65 amps -- plus or minus a few percent depending on the exact  temperature and voltage.  But it would never destroy itself.   Exceptions to this would be if the cooling air were blocked off or if the fan  were not present.

  

 Any copper wire will fry (burn up the insulation) if it gets too hot.   Blow some air on it and it will run cooler at the same current.  Almost any  failure mode will be less at a lower temperature.

  

 Dan Hopper

 RV-7A

  

  

 In a message dated 6/30/2006 4:13:36 A.M. Eastern Daylight Time,  FLYaDIVE(at)aol.com writes:

  	  Quote: 	
		  

LQQK    at what is failing and why.  The problems I see and I have seen a lot,    

way more than 2 planes; is the install.  

Belts too tight

Belts    too loose

Alignment of the alternator sheave to the ring gear out of    whack

Wrong Belts being used - There is a difference in 'V' grove between    aviation 

and automotive.

Belts not seating properly in the    sheave

Alternator not mounted secure - Too much vibration

Cracked    alternator mounts 

Cracked alternator tension brackets

Improper nuts    & bolts used - Course thread Vs fine thread

Ridiculous stacking of    washers in attempts to align alternator with ring gear

Bracket mounting    bolts not torque correctly

No safety tabs on mounting bolts

No safety    wire on tension bracket bolts

Safety wire installed incorrectly

OVER    torquing of Field and B+ nuts

No securing method on alternator    bells

Improper wire length and No service loop on alternator wires

POOR    electrical grounds on the entire engine and plane



So, you can see, you    have to LQQK at the entire picture and not micro manage 

one device.     



Barry

"Chop'd Liver"



QA/QA Manager

SPC

Q1

ISO    9001

Tech Sales Engineering

A&P

chaztuna(at)adelphia.net
Guest

Posted: Fri Jun 30, 2006 6:07 am Post subject: Alternator failure. Info provided

 	  Quote: 	
		  snipped

Brian:



Someone is feeding you a bunch of bunk!

DON'T SPREAD THE BUNK!

Hot rated ... MADE UP NONSENSE!

snipped

As far as auto Vs plane alternators ... Give me a NEW auto type any day.

They keep up with technology.

Don't believe it?  Look at the smaller size and higher output that we have

today.  Other than big business using data such as MTBF to set up a warranty

program ... YES, they reduce the quality of the components to keep 

operational

times just a farts breath longer than the warranty period.  THAT is 

why I do not

rebuild with OEM parts.


	


Barry,

  I work on auto electrical systems every day. I take exception with 

your opinion that OEM parts are all junk. Some manufacturers have cut 

back on parts quality. They are used in by only certain 

manufacturers. They are the ones you hear being on the verge of 

bankruptcy on the TV news.

  Nippon Denso is not one of them. ND electrical parts are extremely 

reliable, as are ND factory remanufactured. My experience is that the 

re-mans sold by discount auto stores like Advance Auto Parts and Pep 

Boys use much lower quality components in their remanufactured parts. 

Sure, they offer life time warranties. What do they care? Their unit 

costs are very low (thanks to using cheap parts and labor). In 

addition, they aren't the ones doing the labor twice (or more).

  As a professional auto mechanic, using poor quality parts is bad 

business for me. I only get paid once. My customer wants the repair 

done correctly the first time. If the repair fails, I get to fix it 

again for free the second time. Add to that, customer ill will, and 

it adds up to a losing proposition for me. Having an electrical 

component fail away from home gets expensive for all of us, as 

aircraft owners. Loss of time gets expensive, if you have to pay for 

overnight shipping, or worse, a rental car and a motel room.

  Buy B&C Specialties or purchase from an auto parts source. Just 

make sure you get high quality parts. You can't go wrong with genuine ND parts.

Charlie Kuss

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