Sonerai Alternator Regulator/Rectifier

You could also try the 'regulator' from your rotax dealer for the 912 -
altho it's truly overpriced for the crude job it does.

I'd think that an automotive regulator would be the best choice also, if
they can indeed handle the crude output waveforms.

Cheers,
Pete
Europa A239

"Model Flyer" wrote in message
...

"AWV" wrote in message
...
Hi,
Got a little Sonerai that runs a VW 1835cc motor with a Great
Plains
alternator that runs on the Flywheel end of the crank. I had a
homemade
rectifier regulator that is giving problems. I am thinking that
maybe there
could be an off the shelf automotive type regulator/rectifier that
would
suite for this purpose? I tried talking to a number of local spares
shops
and automotive auto electricians, but no success.


I think it's the motorcycle crowd that you want to enquire from. some
bikes use simmilar crude alternator systems that use very simple
regulator systems.
--

.
--
Cheers,
Jonathan Lowe
modelflyer at antispam dot net

Antispam trap in place


The basic specs a
1. Two wires come from the alternator.
2. Voltage between the two wires vary between 25VAC and 40VAC
depending on
RPM.
3. Also Voltage between each individual wire and ground is between
12.5VAC
and 20VAC depending on RPM.

I have found the test instructions on the Great Plains web site and
all that
tests OK.

Any ideas on what regulator/rectifier would work for this scenario?
And also how to connect it?
Regards
Andre

Andre,
Yes, this approach works. I have a '71 Norton Commando (British 750cc
twin)that has a similar alternator (see later comment on "similar").
Norton uses a two-wire alternator that produces about 18 or 20 VAC at
a couple thousand rpm. The AC is rectified and applied directly across
the battery. There is a high-current 13 (approx) Volt Zener diode
also across the rectifier/battery to provide some shunt regulation to
avoid overcharging the battery. The variation on this theme is to
eliminate the battery and allow the Zener to "regulate" and stabilize
the voltage. This is the scheme I am currently using with my Norton.
The Zener must be sized (power rating) to be able to handle (ie.,
waste (turn into heat))the maximum output of the alternator as would
be the case where you had no electrical load on the running engine (no
radios or lights, etc...)
You did not say, but I will assume your VW has a starter so you will
be using a battery.
So, all you need is a:
1) rectifier (full-wave recommended altho half wave is simpler and is
ok if your electrical load is light and you are primarily only
recharging the battery after a start).
2) shunt regulator (Zener diode) of sufficient power handling
capacity. Finding a high-power 13.5 (approx) Volt Zener diode may be a
problem. Years ago, thay were common but not so anymore. An
alternative equivalent is to make up a shunt regulator with a
low-power Zener and power transistors.... all cheap parts but requires
some "design" and experimenting.
Now, the comment on "similar". Your reported measurements indicate
that you have a center-tapped alternator winding with the center tap
connected to Ground. My Norton alternator winding is two-wire
floating so a simple full-wave bridge rectifier is appropriate. With
your grounded center-tap winding, you will use what is essentially a
half-bridge.

Also, many (most?) of these type alternator systems use a large
(several thousand microFared) electrolytic capacitor across the system
bus to reduce alternator noise. You may not need this... try without
first.

And finally, as an aside, Revmaster (California VW engine builder)
also uses a simple alternator system.

And really finally, I am not aware of any "off-the-shelf" automotive
solution.
Regards,

Sid Knox
Velocity N199RS
Starduster N666SK
KR2 N24TC
W7QJQ


I think it's the motorcycle crowd that you want to enquire from. some
bikes use simmilar crude alternator systems that use very simple
regulator systems.
--

.
--
Cheers,
Jonathan Lowe
modelflyer at antispam dot net

"AWV" wrote in message
...
Hi,
Got a little Sonerai that runs a VW 1835cc motor with a Great Plains
alternator that runs on the Flywheel end of the crank. I had a homemade
rectifier regulator that is giving problems. I am thinking that maybe
there
could be an off the shelf automotive type regulator/rectifier that would
suite for this purpose? I tried talking to a number of local spares shops
and automotive auto electricians, but no success.

The basic specs a
1. Two wires come from the alternator.
2. Voltage between the two wires vary between 25VAC and 40VAC depending on
RPM.
3. Also Voltage between each individual wire and ground is between 12.5VAC
and 20VAC depending on RPM.

I have found the test instructions on the Great Plains web site and all
that
tests OK.

Any ideas on what regulator/rectifier would work for this scenario?
And also how to connect it?
Regards
Andre


I am certain that one of these will do it for you:

http://mikes.automated-shops.com/cgi..._prod.html?p_p


beware the line wrap. The two yellow wires connect to your two wires coming
from your alternator. The red wire goes to battery "+" and the black wire
goes to battery "-". Bolt it to some metal part of the airplane for a heat
sink. You can get these at most any snowmobile or jetski shop.

Sorry I'm a bit ignorant?
What do you mean by "beware the line wrap?"
Does this device rectify between the earth centre tap and the two yellow
wires or is it only dependant on the output from the two wires coming from
the alternator?

"Jerry Wass" wrote in message
...
Also, a lot of the smaller farm & garden tractors, riding mowers etc have
this
type regulator, Jerry.

Rick Pellicciotti wrote:

"AWV" wrote in message
...
Hi,
Got a little Sonerai that runs a VW 1835cc motor with a Great Plains
alternator that runs on the Flywheel end of the crank. I had a
homemade
rectifier regulator that is giving problems. I am thinking that maybe
there
could be an off the shelf automotive type regulator/rectifier that
would
suite for this purpose? I tried talking to a number of local spares
shops
and automotive auto electricians, but no success.

The basic specs a
1. Two wires come from the alternator.
2. Voltage between the two wires vary between 25VAC and 40VAC
depending on
RPM.
3. Also Voltage between each individual wire and ground is between
12.5VAC
and 20VAC depending on RPM.

I have found the test instructions on the Great Plains web site and
all
that
tests OK.

Any ideas on what regulator/rectifier would work for this scenario?
And also how to connect it?
Regards
Andre


I am certain that one of these will do it for you:


http://mikes.automated-shops.com/cgi..._prod.html?p_p


beware the line wrap. The two yellow wires connect to your two wires
coming
from your alternator. The red wire goes to battery "+" and the black
wire
goes to battery "-". Bolt it to some metal part of the airplane for a
heat
sink. You can get these at most any snowmobile or jetski shop.

Wow!
Suddenly it makes perfect sense! Thanx.

"Morgans" wrote in message
...

"AWV" wrote in message
...
Sorry I'm a bit ignorant?
What do you mean by "beware the line wrap?"
Does this device rectify between the earth centre tap and the two yellow
wires or is it only dependant on the output from the two wires coming
from
the alternator?

It has nottin' to do with the regulator. What he mean is, that the link
that he gave you will most likely not work when you click on it, because
it
is so long that your browser will split it into two separate lines. Thus
the browser is "wrapping" the link, instead of keeping it together so it
will work.
--
Jim in NC

P.S. The only dumb question is the one left un-asked. :-)