'Thane,
HMMMMM... It's easier to group them by manufacturer. Fairchild Na-1,
and nearly all Delco Remy are A circuit. Nearly all Bendix/Eclipse
are of the B variety. Yes the markings can tip you off. The difference
lies in how the fields are controlled. If you can look at the brush
leads and terminals, there are (on our simpler stuff) 2 brushes and
their respective leads, there should also be 2 leads from the fields.
Now most times one of the armature leads is grounded internally and
one is insulated and is the one that pours out the juice. IF THE
GENERATOR FIELD COIL LEAD IS CONNECTED TO THE INSULATED BRUSH INSIDE
THE GENERATOR, THE GENERATOR IS AN "A" TYPE CIRCUIT. IF THE GENERATOR
FIELD COIL LEAD IS CONNECTED TO THE GROUNDED BRUSH INSIDE THE
GENERATOR OR TO THE GENERATOR FRAME, THE GENERATOR IS A "B" TYPE
CIRCUIT.
The big idea here tho' is that A type has the fields fed system
voltage and the regulator controls the field through the ground lead.
Type B has the fields grounded and the regulator controls the power
going TO the fields. Sort of like putting a toggle switch between the
battery and a light bulb (type B), or putting the switch after the
bulb but before the ground or return path(type A).
We have seen type A circuit gens converted to B type externally so
be careful and don't assume anything. Open it up and take a peek. And
for Heaven's sake, flash the fields. Hopefully, you will resolve the
situation and should you come up with a properly matched controller.
You will be rewarded with a reliable power source. Many folks are of
the mind that modern alternators are the way to go but these units
suffer many drawbacks that these ol' CERTIFIED generators addressed
nigh on 50 years ago and are forgotten today by many well intentioned
mechanics.
-- In fairchildclub@y..., "pt19b2001" wrote:
> Is there a way to tell the difference between "A" circuit and "B"
by
> just looking at the generator?
>
> Thane Riffle
>
>
> -- In fairchildclub@y..., "ranger440c5" wrote:
> > Thane,
> > Try Zeftronics 1-800-362-8985. I know they have a generator
> > controller ( I call it a controller as voltage regulation is a
third
> > of its function, the rest being reverse current and overload
> > protection) for 12V/15A type "A" circuit perhaps they have a 28V
> unit
> > as well. The problem is they will be type A circuit. What gen.
you
> > using? Fairchild/Champion or Eclipse? Fairchild unit is type A
and
> > Eclpise is type B. Both units have isolated leads and therefore
be
> > cleverly dealt with. The skinny is your quandry can be solved but
> > there is a questionable legal manipulation involved as none of
this
> > is approved. Good luck.
> >
> > --- In fairchildclub@y..., "pt19b2001" wrote:
> > > I am in the process of installing an electrical system in my
PT. I
> > > finally found the original type Generator for installation. ( I
> > went
> > > this route so I could use the hand crank starter ) But now I'm
> > having
> > > a hard time finding a compatible voltage regulator 28V 15A. the
> > best
> > > I could find was a automotive type 28V 10A. All of the
> manufactures
> > > list them by part number which does not help me much. Any help
> > would
> > > be much appreciated. By the way my dad owns the other F-45. I
> think
> > > that there are only two flying, my dads and the one in Idaho. I
> > > posted photos in the photos area of the club site.
> > >
> > >
> > > Thane Riffle
'