Fried Alternator?

[Ue413]

Was going to take my A2 on a road trip, got about 15 miles away and started smelling something burnt. Pulled over and could determine source the alternator.

got back in to go back home, and voltmeter drpped into yellow...and stayed there.

when I got back, I turned off top lever, and engine immediately stopped (normally you have to turn off lower lever.)

any one experience this and any thoughts why this happened?

 

[98G]

Sequence counts when shutting down the truck. Bottom lever first for shutdown.

 

[The HUlk]

This is common, see this post...

http://www.steelsoldiers.com/showthread.php?146113-M931A1-losing-magic-smoke

 

[infidel got me]

alt. prob.

Queen had a song called -- ANOTHER ONE BITES THE DUST -- look to the delco changeover-- we have had good results with these and the price is right.

 

[MuleMac01]

By turning the top switch off first you might have damaged alternator, If you did it a few time before this happened.

 

[swbradley1]

I even shut down my 813 in sequence. That way I get into a 939 and I'm ready.

 

[74M35A2]

Stock alternator licks. Just be aware the <$200 Delco conversions are actually non-branded Chinese Delco clones. Some work, some work for only 200 miles, some don't work, and some places don't answer the phone for warranty returns. Pulley also is not a direct swap over. But, you do have a lot of choices.

 

[infidel got me]

74M your not swinging the delco bat today what happened?

 

[todds112]

Yup it fried. Odd, it seems these things come in waves. Lots of recent posts on this. I guess they are all about the same age though. Seems like if you have a m939, you will be replacing an alternator.

 

[Andyrv6av8r]

74M your not swinging the delco bat today what happened?

 

[74M35A2]

I'm not pro-Delco, actually. I work for an OE starter/alternator company that is not Delco, nor Chinese either. I'n trying to establish myself as a distributor for our product, but it may be a conflict of interest.. If so, then I will simply setup my neighbor or friend as a vendor. I want to bring our 130A 24v to save the day against these crummy alts.

 

[The HUlk]

By turning the top switch off first you might have damaged alternator, If you did it a few time before this happened.

I have read some technical material that explains what happens when disconnecting a battery from an externally excited alternator while it is still spinning. It is explained that the output voltage spikes very high as 74M35A2 mentioned in a recent post. This stresses the rectifying diodes frequently damaging them.

It sounds like the OPs alternator died from the same cause as mine did, old age. The thin insulating laquer on the field windings degraded and shorted out. The heat burned off the laquer which smells terrible. I could see small bits of laquer ash emitting from it when it was "frying".

 

[Ue413]

When you think of the amount of electrical demand on this alternator and compare to hours of use, I've got equipment with smaller alternators, greater loads, and 10x the hours and still going strong. Hard to reconcile.....

 

[Justgaudot]

Also one thing to consider when replacing or rebuilding that alt. Make sure whatever you get is insulated to handle complete immersion into water. I know it sort of goes without saying but what a bad day that could be on the trail.

 

[silverstate55]

Mine fried on the drive home after the Veteran's Day parade...I always shut down in proper sequence so it must just be age/vibration/etc.

Crap.

 

[74M35A2]

Just a low cost design. Not a robust part. Operates with little to no margin in new condition in a new system. Age and heat cycle it a few times, throw in some hungry batteries, and it is doomed. Lots of threads of them self destructing attempting to charge low batteries. That's silly, as that is its dam job. This is mostly a cooling air issue, the regulator components are not a high enough temperature rating to do full field with low alternator cooling air flow. I'm an alternator guy, and the stock one is still in my truck, but I run a pretty busy schedule at work and home, so I'm not swapping parts just to do it yet unless it fails. These stock alternators are best to be smelted down and molded into pretty Christmas tree ornaments.

 

[swbradley1]

I'm not pro-Delco, actually. I work for an OE starter/alternator company that is not Delco, nor Chinese either. I'n trying to establish myself as a distributor for our product, but it may be a conflict of interest.. If so, then I will simply setup my neighbor or friend as a vendor. I want to bring our 130A 24v to save the day against these crummy alts.

So are you saying you have a higher capacity alternator available somewhere?

 

[74M35A2]

Yes, there is one in my garage.

Over double the capacity, and half the size. 130A, twin fans, temperature compensated voltage regulator, and even spits out duty cycle load % (PWM). Remote sense terminal but not required to use. Super reliable. Includes 8 rib serpentine pulley. Fits SAE standard J-180 short mounts. Can be adapter to long mount with a spacer. Can trade pulley out for V belt type.

But, if I list it for sale here, I'll be spanked for selling in a thread, and double spanked for acting as a vendor without being one. You know how those moderators are.

You can currently buy it on the market, but at what I call an unreasonable price level, almost $400. I want to bring it here at the $250 price point and 3 year warranty.

 

[infidel got me]

So how hard is it to become a vendor?

 

[74M35A2]

On here, simple, just pay a very reasonably small fee. It is securing the product from my work legitimately that take a pinch longer.