What can fry an alternator?

43mod

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Sure sounds like the alternator is a symptom not a cause . If you have been through 5 of them and do not have a separate ground wire yet do it now .
 

Chris_Wilson

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Could it be overheating because its next to the header or mounted such that the fan is blowing backwards (like on a motor plate facing away from engine so its spinning reverse?)
The other thing to check is the rpm it's spinning. You know your engine rpm, then just multiply times the ratio of the crank pulley to alternator pulley. They quit with too much rpm.
It it getting excessive silt dumped into it because of the layout of your car? Maybe a shield to reduce this? I've seen a 2-16 car with dual alternators mounted (second as a spare with belt in place but zip tied out of way for quick activation). But this was back in the days of high current draw lighting.
 

Reece Pettersen

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My family is putting a 1k bounty on this issue. Come fix the problem, if it makes it 1000 miles without blowing an alternator you get paid $1000

Call Jim at Richer Auto & Truck Electric in Oceanside. He is the best when it comes to alternations and solving issues. Lots of experience with off-road race cars too. Tell him I sent you!
 

brad inch

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ok ,its time to stop dicking around. build a complete STAND ALONE system. just run a new wire straight from the batt to the dash.put a new on /off switch .just for this wire only. go next to the lite or gauge ,then straight to the alt. then run + side of the alt straight to the batt.next run a ground from the alt housing staight to the batt.if this works then you can put in relays,fuse,bs. all change out the lite or gauge and batt.

if this does not work,then its heat.the backing sheet metal installed wrong, or to many rpm.


if this does not work you will need to call a priest.

tell your dad and uncle i said hi.

again all of this system must be stand alone only.
good luck brad







=
 

Racer Tim

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Sounds to me like Motor to chassis to battery ground's
I'd definitely agree with with the issue being related to ground strap between motor and chassis or motor and alternator.

The symptoms are right, when a motor is cold it may make a decent enough ground through the motor mounts or else where but when its hot and the alternator is drawing high amounts your ground is going away and it burns them up, we had it happen on a prerunner with a bad ground strap.
 

jon coleman

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i remember that sheet metal thing when i switched my bug from a generator to an alternator, it was important on the cooling requirements( bet the problem is a gremlin thats so obvious it is overlooked, all my troubleshooting fiascos were that simple stupid overlooked thing
 

Jacob Wisdom

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Sounds to me like Motor to chassis to battery ground's
We were concerned about the same thing so added an auxiliary grounding strap from the alternator straight to a bare metal ground on the chassis. Wasn't it unfortunately
Sure sounds like the alternator is a symptom not a cause . If you have been through 5 of them and do not have a separate ground wire yet do it now .
Absolutely, that was one of the first things we tried
try a napa generic stock alt , sometimes ' trick racing' stuff sucks
We tried everything from stock to trick, no change
Could it be overheating because its next to the header or mounted such that the fan is blowing backwards (like on a motor plate facing away from engine so its spinning reverse?)
The other thing to check is the rpm it's spinning. You know your engine rpm, then just multiply times the ratio of the crank pulley to alternator pulley. They quit with too much rpm.
It it getting excessive silt dumped into it because of the layout of your car? Maybe a shield to reduce this? I've seen a 2-16 car with dual alternators mounted (second as a spare with belt in place but zip tied out of way for quick activation). But this was back in the days of high current draw lighting.
We considered heat but it was not an issue when we won SF250 so it's difficult to accept that it would spontaneously become a problem.

Likewise for the car's layout, this is an older Raceco chassis with thousands of race miles. It was never a problem before
Call Jim at Richer Auto & Truck Electric in Oceanside. He is the best when it comes to alternations and solving issues. Lots of experience with off-road race cars too. Tell him I sent you!
Thank you for the recommendation, they did consult with Richer on this issue
ok ,its time to stop dicking around. build a complete STAND ALONE system. just run a new wire straight from the batt to the dash.put a new on /off switch .just for this wire only. go next to the lite or gauge ,then straight to the alt. then run + side of the alt straight to the batt.next run a ground from the alt housing staight to the batt.if this works then you can put in relays,fuse,bs. all change out the lite or gauge and batt.

if this does not work,then its heat.the backing sheet metal installed wrong, or to many rpm.


if this does not work you will need to call a priest.

tell your dad and uncle i said hi.

again all of this system must be stand alone only.
good luck brad







=
The car was completely rewired twice to try and fix this, still failed. One major difficulty is that it takes as much as 100 miles to fail, so proving a solution is very time consuming.

It's time to call a priest.

I'll let them know you say hi!
I'd definitely agree with with the issue being related to ground strap between motor and chassis or motor and alternator.

The symptoms are right, when a motor is cold it may make a decent enough ground through the motor mounts or else where but when its hot and the alternator is drawing high amounts your ground is going away and it burns them up, we had it happen on a prerunner with a bad ground strap.
I wish you were right! We isolated this possibility early on by adding a grounding strap
I recommend that last page. To late now, they are in Baja.
They consulted early on with him. Initially we wanted to have him look the failed alternator over to offer insight but his availability was very limited
every original tip has been repeated
Indeed, by us and by every pro we have had look over the car. We have implemented every credible suggestion
i remember that sheet metal thing when i switched my bug from a generator to an alternator, it was important on the cooling requirements( bet the problem is a gremlin thats so obvious it is overlooked, all my troubleshooting fiascos were that simple stupid overlooked thing
You may be right, it has still not been discovered
 

Jacob Wisdom

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With no clear solution, we've been forced to withdraw from the race. We have implemented every credible solution and still have continued to experience the issue.

We're honestly in disbelief about this and it's hard to say where to even go from here, aside from putting hundreds of miles on the car while isolating each system separately until we find the culprit. It could be as simple as an internal fault in the radio, but if that's the case then it's only occurring in certain conditions because we have measured draw of every circuit separately and together, nothing is drawing more than is expected while sitting. Maybe in the rough that changes.
 

JEFFRPM

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Just remember to tell us what you found
These type things intreage me just by finding out absolutly without a doubt what the problem REALLY is
Knowledge is power



Although painfully sometimes
 

green787

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With no clear solution, we've been forced to withdraw from the race. We have implemented every credible solution and still have continued to experience the issue.

We're honestly in disbelief about this and it's hard to say where to even go from here, aside from putting hundreds of miles on the car while isolating each system separately until we find the culprit. It could be as simple as an internal fault in the radio, but if that's the case then it's only occurring in certain conditions because we have measured draw of every circuit separately and together, nothing is drawing more than is expected while sitting. Maybe in the rough that changes.
Bring it to my shop in Pasadena.... I would like to have a shot at it....
 

jon coleman

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like i said, its most likely gonna be a simple item, like, the ground wire install, was it checked?, are all connections soldered or just crimped?, i like the stand alone t/s method, eliminating the current wiring job& adding a Very rudimentary charging system to run Just the engine , then test to see if it fails, then if so call the priest..
 

partybarge_pilot

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Ok, went back and reread some of it, you said they looked like they were getting hot. What belt setup? Picks of it? Propper tension?
 

WALSHMOTORSPORTS

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What’s up guys. I have chased the same problem before. I’ve had the 4+ alternator race.
1 of the big things I did learn that if u roast the 1st alternator then u drive 20 minutes not charging then u pull into your pit, install the new alternator, get it started and take off!
This is where the next problem started.
Your car has say 40 Amps running stuff. U got a 75 amp alternator. That should be ok but now you asking your alternator to charge a 680 battery too. That’s where the chain effect of failure comes in.
If u roast an alternator u need to rapidly charge your batteries in ur pit for a good 20-30 minutes.
This really helped me out. The alternator is not a battery charger. It’s there to run accessories and sustain the voltage. Make sure batteries are fully charged!
Hope this helps. Good luck and be safe!
 

5racer

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are you running a 911 fan shroud and fan if so and you are using the fan ring for a ground move it to a different spot.
 
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