The high end cars nowadays have water-cooled alternators, using 200 deg water.

 

FYI, those are called TEWAC's.
https://forums.cat.com/t5/Power-Gene...tem/td-p/11620

 

Those alternators probably don't run in excess of the maximum ratings where a LOT of automotive alternators (GMC Suburbans and Ford F-series trucks to name a couple) end up running near max current ratings a lot and are positioned right behind the radiator fan.


"cooling" air in that case ends up at around 200+ deg F. Dropping the air supply 100F would make a pretty big difference.

Also, a lot of the problem alternators in cars and trucks today are supposedly "rated" at 100A or more but are really no different than lower 40-60A models. They'll produce 100 or more amps but only for a very short period because of the heat rise. but run them at max "rating" continuously and they get really hot....... cooler (than 200F) air would certainly mitigate that....

I would bet that most ag equipment are getting alternators that are realistically and conservatively rated.

ANY TEFC machine (AC, DC, 3-PH Synchronous, etc electric motor or generator) is designed to run continuously at rated speed and torque indefinitely [with a specified maximum temp rise over a specified ambient temp range] Non-automotive stuff is frequently rated for -20C to +40C ambient temps etc....

Automotive under-hood temps are higher and have gotten higher over the years.

Providing a cool(er) source of cooling air to an alternator will probably always be better than the hot blast from the radiator.

Here's a great article on it. https://www.electronics-cooling.com/...r-electronics/

 

Our trucks have a lot more room under the hood and the power requirements are significantly less than more modern vehicles. The under-hood temps are certainly less with no-catcons or other emission controls. One of the biggest draws are non-LED high intensity headlamps. Of course they usually are used at night when the ambient temperatures are lower.

Even on todays vehicles alternators are a very reliable component and OEM warranty is relatively low.

 

I would agree with that generally......I bought my 94 Surburban new and sold it in 2014.

Had it 20 years! I was on the 3rd alternator when I sold it! Not all that bad I suppose. But they ran REALLY HOT being right behind the radiator and fan output.

Luckily 2 of them were "lifetime" warranted!

I suspect I would have not had a failure if I had plumbed some "cool" air into it.

 

1234567890

 

Built on a Monday during hunting season? I think that I would be looking somewhere else other than the alternator for root cause of these failures. Maybe loose or bad wiring, accessory problems, etc. Cooling might have just masked the problem until rapid oxidation occurred at the fault.

 

Rebuilt alternators, even the "lifetime" warranted, have very few truly new parts in them. They aren't expected to last a real lifetime, it's just a sales tool.

I had a Bosch alternator rebuilt at a local shop. They had a 55-gallon drum of alternator bearings that they'd pulled out during rebuilds. Someone picked them up monthly. I remarked that bearing steel was likely worth quite a bit. He said, oh, they don't smelt them, they re-use them in China... even re-grease them and package them in SKF/Timken boxes and sell them, "Just look on eBay"....

 

I'm a novice at the electrical side of things, so I bought Vintage Auto Garage parts put together as a kit. Kinda pricey but having all or more than I needed to do the job was also reassuring.

I replaced the battery, installd a 100 amp alterntor, replaced the coil, starter selenoid, light bulbs. I installed a resister for the heater blower, tried to install one for the wipers but put it in backwards and burnt it. They also sold me resistors for the guages, but so far they are working except for the charge indicator light. I also replaced the horn relay. The starter is the original 6v and it whizzis.

When I switched to negative ground I found that the coil had been wired backwards. It worked, but not as it should I've read somewhere.

Hope this helps. Good luck!

 

It was more likely the OEM alternator was just undersized for the job. If you turned all the accessories on and then turned on the rear defogger, you came dangerously close to or exceeded max current output. Since everybody used the front and rear air and other "stuff" it placed a very heavy draw on the alt. An external cooling air supply would have probably helped.

But I suppose but the real "fix" would have been an alternator rated for at least 50% more current.

On many of the newer trucks, FOMOCO has even added a second alternator. I know my 2005 F350 had that option.

 

I noticed the 6 volt positive ground heater motors I have from a 54 and a 55 run the same way if run on 12 volt. I assumed they would turn the wrong way if ran on neg ground, but no they both turn the same way if tested on the bench using a 12 volt battery, reversing the leads, I'm pretty sure they are running faster than intended for 6 volt. I am hoping to find a complete heater assembly from a 56 and also a wiper assembly but pretty tough around here being that 56 was a stand alone year. My truck is a hodge podge between a 55 truck and a 56 dash/windshield/roof/ doors. I also bought it as a basket case with a lot of parts/wiring in boxes. I know the 57 heater assembly was completely different but I wonder if just the motor would work??

 

I used a kit produced by these guys. It included everything needed for the conversion to 12 volts. The alt, lights, coil, regulator, everything. All of it, including the new alt mount, for a 2/3 of the price Vintage Auto Garage charges.

Certified Auto Electric, Inc. They have a facebook page and sell from the store and ebay.

 

Somehow I'm not surprised....
I work for a bearing manufacturer that builds most of their stuff in old Federal Mogul plants back East that we bought from them when they decided to overseas source most of their stuff. I've been "eating their lunch" for a few years now and slowly taking over their accounts. Let 'em play their Chinese games, I've got bonuses to earn.

Here's my 12si Delco alternator bracket......