generator--alternator

[whizzernick]

I am told that someone has a alternator that looks like stock 33-34 generator.
if so i wonder if it charges at idle ? also a friend has a look alike model a gen-alt he says it must have high rpm to charge ?

[rotorwrench]

Alternators and generators both require rotation to generate a current flow and the speed or rpm of that rotation varies from one design to another. On an alternator, the voltage control system also plays a part at what rpm the unit starts to generate. The generator depends on the cut out for the same thing. Most alternators are set up to be controlled by solid state control units either internal or external. Rotation speed depends on the idle speed of the engine and the ratio of the drive pulley sheave by it's diameter. Different size pulley sheaves can be used to slow down some units and speed up others. The other concern here is the fan when it's attached to the drive sheave. A very small sheave may over speed the fan at high rpm if the blades are very long so there can be limitations there. Obviously the sheave can only be so small and still hold a fan so that's another limitation.

In any case the alternator should start to generate very close to the idle speed. If not then there may be a problem with the alternator's control system. I would contact the people that make the alternator and ask them. They should know. If this is for a B motor then I'm not sure who alters them. Most just have a late type alternator installed. There are less limitations on them.

[51504bat]

Check out E.J. Whitney Company in Fullerton, CA. Nice units but not cheap.
http://www.ejwhitneyco.com/automotive.html

[whizzernick]

thanks

[Drbrown]

I've had both "one-wire" and "three-wire" Alt's in my '47 .... non-stock looking commonly available Delco 10's and 12's. I don't know the "engineering" but the one-wire needed to be raised above idle for the Alt's "exciter" to trigger charging. The three-wire, properly connected, generates a charge at any rpm.

[JSeery]

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The Whitney conversions are not the GM/Delco style of alternator so they work a little different. They will build them as a one-wire or I believe what they call a two-wire. The Delco one-wire issue is somewhat unique to these alternators (which work better wired as a three-wire). However, any alternator or generator is going to require some rpms and flatheads are capable of idling at very low rpms.

[cas3]

this topic comes up often, and i wonder why anyone would care if its charging at an idle? heck my ol' 56 bmw bike running on magneto (too poor to buy a battery) would have no lights at all when sitting at a stop light unless i gave it some throttle, which i only did when when other traffic was around. damn kids! but, any way most my cars do not charge much at idle and i dont worry about it

[john in illinois]

The Whitney alternator uses the stock Ford generator pulley and will not charge at idle due to the large diameter of the pulley. As you take off it charges fine. This is a non issue. we usually do not have air conditioners etc running at idle. If you have a lot of extra loads, then this is not for you.

I do have Halogen lights, but the Whitney keeps my battery charged fine.

John

[Bored&Stroked]

Well, my roller-cammed flathead 'idles' at about 1100 RPM . . . and after starting, I see the Whitney alternator pretty much peg the 20 amp gauge. It doesn't take long for the AMP gauge to get back to zero - just a few minutes.

[whizzernick]

Not to change subject . Roller-cammed flathead ????

[38bill]

My one wire alt charges just fine at idle but you have to blip the throttle (or start driving) to raise the rpms to the get it to start charging.

[supereal]

Be advised that the popular GM alternator used for "one wire" conversionss requires more rpms than the old cars can provide at idle. We made a smaller pulley for it, but still have to use high engine speed to turn it on. That requires very tight belt tension which is hard on the water pump bushings. I finally installed a push button switch to kick it on.

[Bored&Stroked]

Originally Posted by whizzernick

Not to change subject . Roller-cammed flathead ????

Yes - and a big ole' nasty one at that! LOL. It is .420 lift and a huge amount of duration - 272 degrees at .050, 314 degrees advertised.

I worked with Ed Isky when I was about 21 years old to make the cam ---> I made the billet cores and he ground the profiles. Sat in a box for 35 years - decided I needed to "build an engine for it" . . . 4 1/8" stroke by 3 5/16 bore . . . is in my 32 Cabriolet.

I wondered if I could run it on the street - given the duration, aluminum flywheel and 25T Zephyr gears. Surprisingly, it runs really well - and sounds better than just about any engine I've built (other than a blown one). I obviously have open headers below . . .

On the dyno:

https://www.youtube.com/watch?v=BIP-62vgtuw

Idling in the Garage - Prior to heading to a show:

https://www.youtube.com/watch?v=p8ay3IkefVw

Enjoy the flathead music . . .

Dale

[flatford8]

That thing sounds like wicked fun!!!!!.......Mark

[tubman]

Boy, I sure would have liked to have been able to read the numbers on the display when the camera panned over to it. Alas, these poor old eyes could not quite make them out. Would you care to disclose them?

[Bored&Stroked]

Originally Posted by tubman

Boy, I sure would have liked to have been able to read the numbers on the display when the camera panned over to it. Alas, these poor old eyes could not quite make them out. Would you care to disclose them?

It made right at 150 HP at the rear wheels. The probably equals somewhere around 170 - 190 at the crank.

It could surely use more carbs, but I wanted to keep it with the early 40's style - so I'm stuck with 2 Stromberg 48's at the moment.

I am going to try a couple Holley 2110's on it - and port the riser - just to see if more air helps. I damaged the stock rear in that dyno pull (the early/weak one), so I'm building a 33/34 for it - with a Columbia on the outside and 8620 steel Columbia parts and 8" Ford 28 spline axles. The stock rears are just a bit weak for flogging!