-------------- Original message from Charlie England <ceengland@bellsouth.net>: --------------


> Marv, I hope this doesn't step on too many toes, but here goes:
>
> Well, he did identify himself as having a financial stake in his
> statements.
>
> Some of that stuff is probably true for *some* a/c alternators. Some of
> it is not universally true; some may not be true, period. Some alts have
> canted brushes, some have perpendicular brushes. Fan orientation will
> affect airflow to some degree, but thousands of auto alts. are being run
> successfully in a/c with no fan at all, using blast tubes. The ones with
> fans still attached still move air when spun the other way. Some car
> engines spin the alt in the same direction as a/c engines. Some a/c alts
> might have locking tabs, but not all. According to auto docs, some auto
> alts are wound delta & some are wound Y. He mentions that alts are
> birotational then later says that a/c alts are wound backward for
> backward rotation. He says that the rotor shaft is shorter but the cases
> are identical. While he's probably correct about special insulations,
> coatings, etc for turbo'd & turbine hardware designed for extreme
> altitudes, I strongly doubt that much if any of that applies for stuff
> found on NA piston singles. It doesn't seem to apply for some electric
> gear retract pumps, which are straight out of marine outdrive tilt
> mechanisms. I've witnessed certified a/c alternators work just fine
> after being rebuilt in greasy floored auto electric shops with auto
> components. Not on my airplane of course... If anyone needs something
> overhauled, bring it with you to the rotary spring fling thing & we'll
> run it 9 miles down the road to the uncertified repair station.
>
> If there's interest, I'll post the article on the aeroelectric list &
> let Bob Nuckolls critique it.
>
> Charlie
> (feeling irritable after a day of figuring out how much it has cost me
> this past year to have my money spent where & in ways I don't want it
> spent)
>
> Kelly Troyer wrote:
>
> > I do not know about everyone elses engines but my 13B turns the same
> > direction as A/C engines built in the US !! I do not know enough to
> > comment about the other differences noted.......
> > --
> > Kelly Troyer
> > Dyke Delta/13B/RD1C/EC2
> >
> >
> >
> >
> > -------------- Original message from "Marvin Kaye"
> > : --------------
> >
> >
> > > I thought you'd find this interesting.
> > >
> > >
> > >
> > >
> > > Posted by "Hamid A. Wasti" to the Lancair Mail List:
> > >
> > > I saw this posted on another list. I am passing it along for
> > general
> > > interest, with no warranty for the accuracy of the information
> > contained in
> > > it.
> > >
> > >
> > > From Pifer's Airmotive, Inc. Pontiac MI
> > >
> > > DIFFERENCES BETWEEN AIRCRAFT & AUTO ALTERNATORS USING A FORD
> > BELT DRIVEN 12v
> > > OR 24v ALTERNATOR FOR A COMPARISON
> > >
> > > 1. Although alternators are bi-rotational, aircraft engines turn
> > opposite of
> > > automotive. This means cooling fans must be canted in the
> > opposite direction.
> > > Also, pulley and belt size vary due to coming-in speed.
> > >
> > > 2. The thru bolts are of a higher tensile strength utilizing an
> > > anti-rotation
> > > device in the form of a lock tab. The rectifier assembly has a
> > heavy duty
> > > diode with higher voltage and amp. capacity. Also, one excites
> > at 90 PIV (Peak
> > > Inverse Voltage) and the other at 150 PIV. Radio suppression is
> > designed for
> > > 108 frequencies and up which is the VHF and 108 and down which
> > is FM band.
> > >
> > > 3. The brushes have a higher graphite content and they utilize a
> > tin plate
> > > on
> > > the brush leads to prevent corrosion.
> > >
> > > 4. The stator is of the Delta wind rather than the “Y" wind and
> > it does not
> > > utilize the stator terminal. The aircraft unit also carries “H"
> > insulation
> > > which is capable of 200 degrees centigrade temperatures. It also
> > is rated at
> > > 60 amp. instead of 55.
> > >
>
> > > 5. The rotor has a shorter shaft and a smaller thread size.
> > Because of the
> > > opposite rotation it is wound in the opposite direction. It also
> > uses "H”
> > > insulation and Havel varnish.
> > >
> > > 6. The front and rear housings are the same as automotive.
> > >
> > > With this brief description, I hope I have enlightened you on the
> > > differences
> > > between aircraft and automotive alternators. Using automotive
> > units in an
> > > aircraft creates a potential safety hazard as well as a short
> > alternator life
> > > and unreliability.
> > >
> > >
> > >
> > >
> > >
> > >
> > > >> Homepage: http://www.flyrotary.com/
> > > >> Archive: http://lancaironline.net/lists/flyrotary/List.html
> >
>
>
>
> >> Homepage: http://www.flyrotary.com/
> >> Archive: http://lancaironline.net/lists/flyrotary/List.html