More efficient alternator/power usage


8thTon

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20 some yrs ago I had an electric radiator fan and a heater blower fan motor lose their magnetics. (GM Pontiacs) Really surprised me too.
To demagnetize the permanent magnets in those motors to the point where you would notice the change would require a massive demagnetizing field or raising the temperature past the Curie temperature, and if either of those things happened the motors would be the least of your worries. Given how unlikely it is to have that happen on two motors (on the same vehicle?), more than likely it was a misdiagnoses and the real problem got corrected while the parts were being replaced.

https://sciencing.com/demagnetize-magnet-5071154.html
 


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Denisefwd93

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Different cars and times. We didn't spend a whole lot of time being scientific about it, found they weren't working and replaced them.
 
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Dirtman

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Im no scientist but the magnets themselves wouldn't need to become demagnetized to reduce the efficiency of the magnetic field and in turn raise the current draw on an old motor.

Dirt, hair and typical garbage grinding away at and creating a shield around the armature for 30 years can do that just fine. :dunno:
 

8thTon

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Im no scientist but the magnets themselves wouldn't need to become demagnetized to reduce the efficiency of the magnetic field and in turn raise the current draw on an old motor.

Dirt, hair and typical garbage grinding away at and creating a shield around the armature for 30 years can do that just fine. :dunno:
Magnetic fields go right through those things, you would need a bunch of iron in that dirt to have any effect. Much more likely the brushes wore out or got dirty in those motors. Can't tell you how many failed motors of various types I've fixed simply by taking them apart and cleaning the commutators and brushes with scotchbrite and brake clean. Blower motors, window motors, starters, etc. Grease up the bearings and they're good to go.

They are very simple, but sometimes you have to make some sort of tool to hold the brushes apart while they go back together.
 

Nez'sRanger

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Awesome! I'll clean the blower motor and see how it goes! Gotta wait a couple paychecks to change my alternator, but I can clean that thing any day...
 

4x4junkie

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I put a 95A 3G alternator from a '95 F-150 (300 I6 engine) on my '90 2.9L... The alternator itself bolts up exactly to the 2.9L mounts, other than I recall having to use a different upper bolt or something very minor (I've since removed it to swap to an on-board welder setup, which I had to modify the upper mounting bracket for).

There are some slight electrical modifications that are needed for the 3G unit (which is for the better anyway, this gets rid of that crappy shit plastic plug that likes to burn up on the 2G units), and you'll need to swap the V-belt pulley from your old 2G alt onto it.

This was the best mod I did before I changed to the onboard welder (before that I had tried a 2G unit that was "modified" to be 100A, but even with everything in good order, it couldn't maintain voltage at an idle, which I later found out this is common with such modified alts). The 95A 3G unit however worked flawless.
 

PetroleumJunkie412

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Second on the 3G alternator swap. Pulled mine from a 1995 windstar. Make sure to slice open the harness of the donor vehicle to get everything. The windstar alternator and harness wired up so well that it looks factory. Major improvement across the board, but I run electric fans, a 400w stereo, and 1500w inverter off of mine.

Only modifications I made was to run a 150 amp mega fuse between the alternator and everything else, and a Chevy 350 alternator bracket. Took maybe an hour or two.
 


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