On Wed, 29 Dec 2004 16:17:01 -0800, Frank Gilliland
wrote:

On Wed, 29 Dec 2004 17:55:16 -0600, itoldyouiamnotiamnotgeorge
wrote in
:

Frank Gilliland wrote in
m:

Current equalizing resistors is another way to do it. It's common
practice in SS audio amps to use emitter resistors to equalize the
currents between parallel transistors. But I would hesitate using them
with modern alternators because I don't know how it would screw with
the regulators -- some have a local sense line and others have a
remote sense line -- a resistor in the load might send the regulator
into seizures.


Frank it is very easy a single regulator will control the field voltage on
both alternators. This way they would run the same and share the "Load"


I thought about that, but wouldn't the rotors need to be locked in
phase?


Phase? The control voltage is DC, the outputs are DC, am I missing
something? I know that the output of an alternator isn't "pure' DC,
but it will never be 180 degrees out.

On Thu, 30 Dec 2004 16:46:42 GMT, Lancer wrote in
. com:

On Wed, 29 Dec 2004 16:17:01 -0800, Frank Gilliland
wrote:

On Wed, 29 Dec 2004 17:55:16 -0600, itoldyouiamnotiamnotgeorge
wrote in
:

Frank Gilliland wrote in
:

Current equalizing resistors is another way to do it. It's common
practice in SS audio amps to use emitter resistors to equalize the
currents between parallel transistors. But I would hesitate using them
with modern alternators because I don't know how it would screw with
the regulators -- some have a local sense line and others have a
remote sense line -- a resistor in the load might send the regulator
into seizures.


Frank it is very easy a single regulator will control the field voltage on
both alternators. This way they would run the same and share the "Load"


I thought about that, but wouldn't the rotors need to be locked in
phase?


Phase? The control voltage is DC, the outputs are DC, am I missing
something? I know that the output of an alternator isn't "pure' DC,
but it will never be 180 degrees out.


Auto alternators are three-phase alternators. As such, the rectified
output never drops to zero, but it does have significant ripple. The
regulator obviously controls the DC component. So I guess the question
is if the regulator also smooths the ripple. If it does then parallel
alternators must be locked in phase. But if it just controls the DC
component then current equalizing resistors will do the job (although
I would think about putting a ripple filter on the sense lines).

http://www.geocities.com/mopedzadumd...?1082158996910

"Lancer" wrote in message
ews.com...
On Wed, 29 Dec 2004 16:17:01 -0800, Frank Gilliland
wrote:

On Wed, 29 Dec 2004 17:55:16 -0600, itoldyouiamnotiamnotgeorge
wrote in
:

Frank Gilliland wrote in
:

Current equalizing resistors is another way to do it. It's common
practice in SS audio amps to use emitter resistors to equalize the
currents between parallel transistors. But I would hesitate using them
with modern alternators because I don't know how it would screw with
the regulators -- some have a local sense line and others have a
remote sense line -- a resistor in the load might send the regulator
into seizures.


Frank it is very easy a single regulator will control the field voltage
on
both alternators. This way they would run the same and share the "Load"


I thought about that, but wouldn't the rotors need to be locked in
phase?


Phase? The control voltage is DC, the outputs are DC, am I missing
something? I know that the output of an alternator isn't "pure' DC,
but it will never be 180 degrees out.

Alternators deliver 3 phase, approximately 120 volts output at working RPM.

U Know Who wrote:


"Lancer" wrote in message
ews.com...
On Wed, 29 Dec 2004 16:17:01 -0800, Frank Gilliland
wrote:

On Wed, 29 Dec 2004 17:55:16 -0600, itoldyouiamnotiamnotgeorge
wrote in
:

Frank Gilliland wrote in
m:

Current equalizing resistors is another way to do it. It's common
practice in SS audio amps to use emitter resistors to equalize the
currents between parallel transistors. But I would hesitate using them
with modern alternators because I don't know how it would screw with
the regulators -- some have a local sense line and others have a
remote sense line -- a resistor in the load might send the regulator
into seizures.


Frank it is very easy a single regulator will control the field voltage
on
both alternators. This way they would run the same and share the "Load"


I thought about that, but wouldn't the rotors need to be locked in
phase?


Phase? The control voltage is DC, the outputs are DC, am I missing
something? I know that the output of an alternator isn't "pure' DC,
but it will never be 180 degrees out.

Alternators deliver 3 phase, approximately 120 volts output at working
RPM.

Yes I know that, The output (at least on most automotive applications is
DC.)
I have seen modifed alternators with 3 transformers on them to provide
higher voltages for B+ for transmitters.

On Fri, 31 Dec 2004 00:40:51 GMT, Lancer wrote:

U Know Who wrote:


"Lancer" wrote in message
ews.com...
On Wed, 29 Dec 2004 16:17:01 -0800, Frank Gilliland
wrote:

On Wed, 29 Dec 2004 17:55:16 -0600, itoldyouiamnotiamnotgeorge
wrote in
:

Frank Gilliland wrote in
om:

Current equalizing resistors is another way to do it. It's common
practice in SS audio amps to use emitter resistors to equalize the
currents between parallel transistors. But I would hesitate using them
with modern alternators because I don't know how it would screw with
the regulators -- some have a local sense line and others have a
remote sense line -- a resistor in the load might send the regulator
into seizures.


Frank it is very easy a single regulator will control the field voltage
on
both alternators. This way they would run the same and share the "Load"


I thought about that, but wouldn't the rotors need to be locked in
phase?


Phase? The control voltage is DC, the outputs are DC, am I missing
something? I know that the output of an alternator isn't "pure' DC,
but it will never be 180 degrees out.

Alternators deliver 3 phase, approximately 120 volts output at working
RPM.

Yes I know that, The output (at least on most automotive applications is
DC.)
I have seen modifed alternators with 3 transformers on them to provide
higher voltages for B+ for transmitters.

BTW Randy, I wasn't trying to be a smart ass with my answer.

"Lancer" wrote in message
ews.com...
On Fri, 31 Dec 2004 00:40:51 GMT, Lancer wrote:

U Know Who wrote:


"Lancer" wrote in message
ews.com...
On Wed, 29 Dec 2004 16:17:01 -0800, Frank Gilliland
wrote:

On Wed, 29 Dec 2004 17:55:16 -0600, itoldyouiamnotiamnotgeorge
wrote in
:

Frank Gilliland wrote in
news:q9i5t09kfa8oceo2bsc8sp2fri7hl2d4bo@4ax. com:

Current equalizing resistors is another way to do it. It's common
practice in SS audio amps to use emitter resistors to equalize the
currents between parallel transistors. But I would hesitate using
them
with modern alternators because I don't know how it would screw with
the regulators -- some have a local sense line and others have a
remote sense line -- a resistor in the load might send the regulator
into seizures.


Frank it is very easy a single regulator will control the field
voltage
on
both alternators. This way they would run the same and share the
"Load"


I thought about that, but wouldn't the rotors need to be locked in
phase?


Phase? The control voltage is DC, the outputs are DC, am I missing
something? I know that the output of an alternator isn't "pure' DC,
but it will never be 180 degrees out.

Alternators deliver 3 phase, approximately 120 volts output at working
RPM.

Yes I know that, The output (at least on most automotive applications is
DC.)
I have seen modifed alternators with 3 transformers on them to provide
higher voltages for B+ for transmitters.

BTW Randy, I wasn't trying to be a smart ass with my answer.

I didn't take it that way. NP!

On Fri, 31 Dec 2004 00:52:30 GMT, Lancer wrote in
:

snip
I still don't quite see why you would need to have the alternators run in
phase. If you were taking the 3 phase out before rectifying it, yes.


The problem is if they slip out of phase then the ripple from each
will be mixed. At 60 degrees shift the ripple between the two will be
twice that of one alternator. That can't be good for a battery. Also,
as the alternators continue to rotate against each other the output
will change from very smooth to twice as bumpy, and will do so at a
very low frequency. The problem here lies with how the regulator
senses the DC output. It's doubtful that the regulator will see true
RMS, so the result is that you will get a low frequency variation of
the DC output. Another problem is how that variation will be fed back
to the rotors from the regulator..... but that's all moot:

I did a little research and found out that only a few alternators have
regulation fast enough to smooth the ripple. That's good news because
there is no need to use a single regulator or to lock the phase of the
alternators. All that's needed is current equalization with resistors.

And for the sake of mentioning it, I also found out that most of the
newer alternators (like the Delco CS130 in my truck) use a 'switching'
type regulation scheme, which may be why alternator whine in the radio
is becoming much more common.

On Thu, 30 Dec 2004 17:39:10 -0600, itoldyouiamnotiamnotgeorge
wrote in
:

Frank Gilliland wrote in
:

On Thu, 30 Dec 2004 14:59:40 GMT, Lancer wrote in
:

Frank Gilliland wrote:

On Wed, 29 Dec 2004 17:55:16 -0600, itoldyouiamnotiamnotgeorge
wrote in
:

Frank Gilliland wrote in
om:

Current equalizing resistors is another way to do it. It's common
practice in SS audio amps to use emitter resistors to equalize the
currents between parallel transistors. But I would hesitate using
them with modern alternators because I don't know how it would
screw with the regulators -- some have a local sense line and
others have a remote sense line -- a resistor in the load might
send the regulator into seizures.


Frank it is very easy a single regulator will control the field
voltage on
both alternators. This way they would run the same and share the
"Load"


I thought about that, but wouldn't the rotors need to be locked in
phase?

Phase? The control voltage is DC, the output is DC, am I missing
something?


The control (field) current is fluctuating DC, isn't it? Isn't that
how the regulator smooths the output (which would be fluctuating DC if
the field current was steady)?


When the rectified DC from each of the three-phase windings is added
together, the peaks overlap to produce a much cleaner DC with much less
ripple. Lead-acid auto batteries last longer when charged with pure DC
than high ripple rectified DC. Three-phase windings were designed into
alternators to produce DC of great purity.


When you quote someone else it's good practice to cite the source:

http://mysite.verizon.net/res00d4r/a...or_Theory.html

On Fri, 31 Dec 2004 03:24:29 GMT, Lancer wrote in
. com:

On Thu, 30 Dec 2004 18:30:21 -0800, Frank Gilliland
wrote:

On Fri, 31 Dec 2004 00:52:30 GMT, Lancer wrote in
:

snip
I still don't quite see why you would need to have the alternators run in
phase. If you were taking the 3 phase out before rectifying it, yes.


The problem is if they slip out of phase then the ripple from each
will be mixed. At 60 degrees shift the ripple between the two will be
twice that of one alternator. That can't be good for a battery. Also,
as the alternators continue to rotate against each other the output
will change from very smooth to twice as bumpy, and will do so at a
very low frequency. The problem here lies with how the regulator
senses the DC output. It's doubtful that the regulator will see true
RMS, so the result is that you will get a low frequency variation of
the DC output. Another problem is how that variation will be fed back
to the rotors from the regulator..... but that's all moot:

True, I just thought that the battery saw anywhere from 13 to 15 or
16 from the alternator that it wouldn't be all that big a deal.


Feed a charged battery with more than 14 volts or so and it will go
dry very quickly.


I did a little research and found out that only a few alternators have
regulation fast enough to smooth the ripple. That's good news because
there is no need to use a single regulator or to lock the phase of the
alternators. All that's needed is current equalization with resistors.

And for the sake of mentioning it, I also found out that most of the
newer alternators (like the Delco CS130 in my truck) use a 'switching'
type regulation scheme, which may be why alternator whine in the radio
is becoming much more common.


My truck also has that. Mine went out last year, it took three tries
to get a rebuilt replacement that would work correctly. I guess they
have different regulators that sense starting or resting voltage.


Beats me, but from what I have found out so far I'm about ready to
swap mine out for a 10SI I bought as a spare for another truck. It has
a lower current rating, but I've never had one go out on me (hence the
reason I still have the spare).