CASE VAC alternator conversion question

[Soldier Tom]

I have just about got everything ready to go. I noticed however that the alternator will be turning "backwards" when the engine is running. Question is; does this matter? My gut tells me it does.
Any suggestions or advice is welcome.
~Walk in peace~
Tom

 

[Duner Wi]

Should not matter which way it runs. If it won't cool get a fan from a Corvair or a marine reverse rotation engine.

 

[mj]

(quoted from post at 19:29:42 02/26/08) I have just about got everything ready to go. I noticed however that the alternator will be turning "backwards" when the engine is running. Question is; does this matter? My gut tells me it does.
Any suggestions or advice is welcome.
~Walk in peace~
Tom

The stamped metal fan blade that mounts behind the pulley will be running backwards - blowing away from the alternator instead of towards it - as much air as the VAC's fan blows you should be alright though. I'd remove the alternator fan to run it that way. 8)

 

[Bob]

If you have mounted the alternator in place of the generator, it will NOT be turing backwards.

Or, have you mounted it in some obscure fashion?

IF you HAVE mounted it so it actually runs backwards, ELECTRICALLY it doesn't matter. HOWEVER, the pulley is NOT keyed to the shaft, and will tend to loosen the nut, and fall off.

 

[Soldier Tom]

Bob, When I crank the engine over it spins the alternator so that the fan on it runs backwards. I put it right back where the generator was. Durndest thing.
Tom

 

[Soldier Tom]

MJ, that is what I will do. I will pull the pulley back off (That will be fun, it did NOT want to go on to begin with) and run the alternator without a fan for a while until I see if it overheats or whatnot. Thanks much!
Walk in peace!
Tom

 

[Bob]

Tom,

If the alternator is turning CW, looking at the pulley, just like the generator did, it's NORMAL.

The alternator fan blades slant BACKWARDS of rotation, so air is pulley INTO the back of the alternator, pulled through the rotor/stator area, and thrown outward by the alternator's fan.

 

[Soldier Tom]

Thanks much! I appreciate the input. Tomorrow I'll pull it back off and remove the little fan blades. That will help the pulley seat better anyway, it stuck out a little too far for my taste.
Yall are a great information source!
Walk in peace
Soldier Tom

 

[Bob]

DON'T remove the fan. Read my other post as to how the air is drawn THROUGH the alternator, from the BACK to the FRONT.

As the air enters the back, it cools the rectifier and voltage regulator.

With the relatively low amperage that this tractor alternator will be required to put out, you would probably get by with removing the fan, by WHY take the chance... you guys are looking at what the fan does in a BACKWARDS fashion, and ASSUMING it's supposed to blow air INTO the front of the alternator, but that's NOT how it's supposed to work!

 

[Soldier Tom]

Oh, I can see how that would work. Looking at the shape and angle of the blades, I assumed the blades were to push the air from front to back of the alternator.
Do all alternators do it like that? (Did I mention that I am NOT a mechanic and don't claim to be?!) If that is the case, I should not do anything to it, just run it as-is. Right?
Thanks much again, good info!
Walk in peace

 

[Soldier Tom]

Bob, Got it.
I appreciate your taking time to explain that to me. I was doing just what you said. ASSuming that it was working one way when it wasn't. Thanks for setting me right, I will be running it just like it sits, and happy to do it that way.
Again, I appreciate you setting me on the right path.
Walk in peace!

 

[Bob]

I can't say ALL alternators are cooled that way, but MOST common alternators certainly are.

 

[Bob]

We have a lot of (simple) fun around here sometimes, don't we!

How are you doing with the GREEN #5 mower?

 

[Soldier Tom]

Now how about you remembering that?
I plan to use it this spring to mow the hay with and some of the pastures too for kicks and giggles. I got the grassboard finished, and it should be good to go now.
I want to see how the (green)720 does with it. We had it running last fall behind the MF, but not JUST RIGHT. I am kindof anxious to see how the little VAC will do with it too.
Thank you so much for asking!
Walk in peace

 

[Bob]

In my younger years, I mowed more TOUGH prairie hay than I care to remember with a #5. I thought it was NEAT that you were resurrecting one!

 

[greygoat]

If the fan is pulling the air through from the
back to the front...isn't that going to be
opposed by the air being pulled through the
radiater, from front to back?

 

[Bob]

Yep, that's the way it works, and WELL, too, I might add!