EDAboard.com | EDAboard.eu | EDAboard.de | EDAboard.co.uk | RTV forum PL | NewsGroups PL

Automotive alternator windings & rectifier

Ask a question - edaboard.com

elektroda.net NewsGroups Forum Index - Electronics Equipment - Automotive alternator windings & rectifier

Goto page Previous  1, 2

Jasen Betts
Guest

Tue Aug 20, 2013 5:23 pm   



On 2013-08-19, Cydrome Leader <presence_at_MUNGEpanix.com> wrote:

Quote:
dumb question.

what EXACTLY does the charge lamp indicate?


current into the regulator not supplied by the altenator.

> what triggers it to go on and off?

basically a working altenator.

> can it simply be removed and ignored?

you could replace it with a short circuit

--
⚂⚃ 100% natural

--- news://freenews.netfront.net/ - complaints: news_at_netfront.net ---

Jim Thompson
Guest

Tue Aug 20, 2013 9:39 pm   



On Tue, 20 Aug 2013 04:24:20 +0000 (UTC), David Lesher
<wb8foz_at_panix.com> wrote:

Quote:
Mike Perkins <spam_at_spam.com> writes:

Where does the common winding terminal connect (there is a
connection on the rectifier plate)? Where do the other 2 diodes
connect?


That pictured alternator is one used on Hondas. ISTM it's a
Nippon-Densi or such.

I have too much experience with same. I went through 3-4
boneyard ones before I bought a rebuilt one from Retarded Auto
Parts. That brand/model alternator is nice because the diode
array unscrews easily. No unsoldering needed.

That particular alternator has 4 pairs of power diodes; the
center point of the wye has a pair from there as well.... and I
have no idea why... Jim??


They are a multitude of ways to implement the "idiot light" function,
some used relays, some were a part of the regulator.

I'm in the midst of moving right now, old house sold faster than new
one's construction, so I'm stuck in a snow-bird friend's loaner with
no access to my (paper) file cabinets.

When I get back on the air I'll retrieve those drawings and post.

Keep in mind I did no automotive after about 1973, so I'm not up on
any modern approaches.

Quote:

That said, all recent alternators also have a diode trio of tiny
diodes. Their function is to rectify enough power to excite the
rotor. It takes a few amps to drive it. Until it's up to speed,
that excitation comes from the battery, through the red idiot
light. When the alternator is up to speed, there is 12V on the
battery side of the lamp, and 12v on the load side....and it
goes out.


Or, like many GM alternators, the rotor was mildly magnetized to
provide "kick-start", minimum load requirement hidden by the
"daylight-safety" headlamp BS Wink

...Jim Thompson
--
| James E.Thompson | mens |
| Analog Innovations | et |
| Analog/Mixed-Signal ASIC's and Discrete Systems | manus |
| San Tan Valley, AZ 85142 Skype: Contacts Only | |
| Voice:(480)460-2350 Fax: Available upon request | Brass Rat |
| E-mail Icon at http://www.analog-innovations.com | 1962 |

I love to cook with wine. Sometimes I even put it in the food.

Cydrome Leader
Guest

Wed Aug 21, 2013 1:47 am   



In sci.electronics.equipment Mike Perkins <spam_at_spam.com> wrote:
Quote:
On 20/08/2013 08:04, Mike Cook wrote:
Not the alternators I've taken apart. The star point is typically
a crimp, and serves no other useful purpose.

The field, and regulator power, are normally taken from an
additional set of diodes, usually 3, ie one per phase, such that
the regulator is effectively isolated from the battery when the
engine is not turning.

But THAT'S why I'm asking here: this Denso alternator (used in MANY
Hondas, Toyotas, and myriad other makes) does have a common terminal
connection to the rectifier. The rectifier has EIGHT diodes.

Yes I agree that common configuration is 6 diodes. That's why I'm
confused. The system is quite populous and apparently functions. I
just don't understand how.

I can find very little on the web regarding neutral point rectification
for car (Lundell) alternators, but there is a lot about 3rd harmonic
neutral currents. An example how these manifest in electrical systems
for non-linear loads.

http://static.schneider-electric.us/docs/Electrical%20Distribution/Low%20Voltage%20Transformers/Harmonic%20Mitigating/0104ED9501R896.pdf

A conventional automotive alternator uses six diodes to rectify
three-phase AC (Alternating Current) into DC (Direct Current). The
average voltage of the neutral point is 1/2 of the output DC voltage.
While a low output current flows, the voltage at the neutral point is
mostly DC, but it also includes an AC portion. As current output
increases, the AC portion increases.

When the alternator speed exceeds 2,000 to 3,000 rpm, the peak value of
this AC portion exceeds the DC output voltage.

This means that, compared with the output characteristics of the
alternator without neutral-point diodes, the output gradually increases
from midway by 10 to 15% at a normal rated alternator speed of approx.
5,000 rpm.

http://youronlinemechanic.com/alternator-with-neutral-point-voltage/


Here's a diagram of what the above link failed to clearly explain

http://autonopedia.org/renewable-energy/generators/alternator-secrets/

so somehow tapping neutral is good. I guess those two diodes bypass
current flowing int coils the wrong way or something? As to how speed
matters, I'm not following that.

Mike Perkins
Guest

Wed Aug 21, 2013 7:15 am   



On 21/08/2013 00:47, Cydrome Leader wrote:
Quote:
In sci.electronics.equipment Mike Perkins <spam_at_spam.com> wrote:
On 20/08/2013 08:04, Mike Cook wrote:
Not the alternators I've taken apart. The star point is typically
a crimp, and serves no other useful purpose.

The field, and regulator power, are normally taken from an
additional set of diodes, usually 3, ie one per phase, such that
the regulator is effectively isolated from the battery when the
engine is not turning.

But THAT'S why I'm asking here: this Denso alternator (used in MANY
Hondas, Toyotas, and myriad other makes) does have a common terminal
connection to the rectifier. The rectifier has EIGHT diodes.

Yes I agree that common configuration is 6 diodes. That's why I'm
confused. The system is quite populous and apparently functions. I
just don't understand how.

I can find very little on the web regarding neutral point rectification
for car (Lundell) alternators, but there is a lot about 3rd harmonic
neutral currents. An example how these manifest in electrical systems
for non-linear loads.

http://static.schneider-electric.us/docs/Electrical%20Distribution/Low%20Voltage%20Transformers/Harmonic%20Mitigating/0104ED9501R896.pdf

A conventional automotive alternator uses six diodes to rectify
three-phase AC (Alternating Current) into DC (Direct Current). The
average voltage of the neutral point is 1/2 of the output DC voltage.
While a low output current flows, the voltage at the neutral point is
mostly DC, but it also includes an AC portion. As current output
increases, the AC portion increases.

When the alternator speed exceeds 2,000 to 3,000 rpm, the peak value of
this AC portion exceeds the DC output voltage.

This means that, compared with the output characteristics of the
alternator without neutral-point diodes, the output gradually increases
from midway by 10 to 15% at a normal rated alternator speed of approx.
5,000 rpm.

http://youronlinemechanic.com/alternator-with-neutral-point-voltage/

Here's a diagram of what the above link failed to clearly explain

http://autonopedia.org/renewable-energy/generators/alternator-secrets/

so somehow tapping neutral is good. I guess those two diodes bypass
current flowing int coils the wrong way or something? As to how speed
matters, I'm not following that.


If you consider that at any time 2 windings will be supplying one
polarity of current and the remaining winding the other polarity, you
can see the neutral point is going to move in the direction dictated by
the two windings. At higher currents, and higher frequencies, the
inductance of the winding causes an increasing voltage to appear at the
neutral point.

--
Mike Perkins
Video Solutions Ltd
www.videosolutions.ltd.uk

Don Kelly
Guest

Wed Aug 21, 2013 7:24 am   



On 19/08/2013 10:33 PM, Spehro Pefhany wrote:
Quote:
The power rectifiers connected to the Wye common are used to extract
3rd harmonic power- yielding up to 10% additional current capacity-
when operating at high speed.

That doesn't make sense to me. One advantage of 3 phase is the
elimination of triplen harmonics. Now, with a 3 phase bridge-will there
be a significant 3rd harmonic voltage? Certainly,if the wye neutral is
not connected to the DC ground, there is no 3rd harmonic current and
power. Generally this is a good thing.
Somehow, I appear to be missing something-could you elucidate? A circuit
diagram and analysis would help.

--
Don Kelly
remove the cross to reply

Spehro Pefhany
Guest

Wed Aug 21, 2013 7:30 am   



On Wed, 21 Aug 2013 02:15:27 +0100, the renowned Mike Perkins
<spam_at_spam.com> wrote:

Quote:
On 21/08/2013 00:47, Cydrome Leader wrote:
In sci.electronics.equipment Mike Perkins <spam_at_spam.com> wrote:
On 20/08/2013 08:04, Mike Cook wrote:
Not the alternators I've taken apart. The star point is typically
a crimp, and serves no other useful purpose.

The field, and regulator power, are normally taken from an
additional set of diodes, usually 3, ie one per phase, such that
the regulator is effectively isolated from the battery when the
engine is not turning.

But THAT'S why I'm asking here: this Denso alternator (used in MANY
Hondas, Toyotas, and myriad other makes) does have a common terminal
connection to the rectifier. The rectifier has EIGHT diodes.

Yes I agree that common configuration is 6 diodes. That's why I'm
confused. The system is quite populous and apparently functions. I
just don't understand how.

I can find very little on the web regarding neutral point rectification
for car (Lundell) alternators, but there is a lot about 3rd harmonic
neutral currents. An example how these manifest in electrical systems
for non-linear loads.

http://static.schneider-electric.us/docs/Electrical%20Distribution/Low%20Voltage%20Transformers/Harmonic%20Mitigating/0104ED9501R896.pdf

A conventional automotive alternator uses six diodes to rectify
three-phase AC (Alternating Current) into DC (Direct Current). The
average voltage of the neutral point is 1/2 of the output DC voltage.
While a low output current flows, the voltage at the neutral point is
mostly DC, but it also includes an AC portion. As current output
increases, the AC portion increases.

When the alternator speed exceeds 2,000 to 3,000 rpm, the peak value of
this AC portion exceeds the DC output voltage.

This means that, compared with the output characteristics of the
alternator without neutral-point diodes, the output gradually increases
from midway by 10 to 15% at a normal rated alternator speed of approx.
5,000 rpm.

http://youronlinemechanic.com/alternator-with-neutral-point-voltage/

Here's a diagram of what the above link failed to clearly explain

http://autonopedia.org/renewable-energy/generators/alternator-secrets/

so somehow tapping neutral is good. I guess those two diodes bypass
current flowing int coils the wrong way or something? As to how speed
matters, I'm not following that.


If you consider that at any time 2 windings will be supplying one
polarity of current and the remaining winding the other polarity, you
can see the neutral point is going to move in the direction dictated by
the two windings. At higher currents, and higher frequencies, the
inductance of the winding causes an increasing voltage to appear at the
neutral point.


Some more info:-

http://tinyurl.com/kdcsayk

http://ece.ubm.ro/cjece/web/CJECE_VOL5_2012/3_Barz.pdf



Best regards,
Spehro Pefhany
--
"it's the network..." "The Journey is the reward"
speff_at_interlog.com Info for manufacturers: http://www.trexon.com
Embedded software/hardware/analog Info for designers: http://www.speff.com

Don Kelly
Guest

Fri Aug 23, 2013 7:30 am   



On 20/08/2013 8:33 PM, Spehro Pefhany wrote:
Quote:
On Wed, 21 Aug 2013 02:15:27 +0100, the renowned Mike Perkins
spam_at_spam.com> wrote:

On 21/08/2013 00:47, Cydrome Leader wrote:
In sci.electronics.equipment Mike Perkins <spam_at_spam.com> wrote:
On 20/08/2013 08:04, Mike Cook wrote:
Not the alternators I've taken apart. The star point is typically
a crimp, and serves no other useful purpose.

The field, and regulator power, are normally taken from an
additional set of diodes, usually 3, ie one per phase, such that
the regulator is effectively isolated from the battery when the
engine is not turning.

But THAT'S why I'm asking here: this Denso alternator (used in MANY
Hondas, Toyotas, and myriad other makes) does have a common terminal
connection to the rectifier. The rectifier has EIGHT diodes.

Yes I agree that common configuration is 6 diodes. That's why I'm
confused. The system is quite populous and apparently functions. I
just don't understand how.

I can find very little on the web regarding neutral point rectification
for car (Lundell) alternators, but there is a lot about 3rd harmonic
neutral currents. An example how these manifest in electrical systems
for non-linear loads.

http://static.schneider-electric.us/docs/Electrical%20Distribution/Low%20Voltage%20Transformers/Harmonic%20Mitigating/0104ED9501R896.pdf

A conventional automotive alternator uses six diodes to rectify
three-phase AC (Alternating Current) into DC (Direct Current). The
average voltage of the neutral point is 1/2 of the output DC voltage.
While a low output current flows, the voltage at the neutral point is
mostly DC, but it also includes an AC portion. As current output
increases, the AC portion increases.

When the alternator speed exceeds 2,000 to 3,000 rpm, the peak value of
this AC portion exceeds the DC output voltage.

This means that, compared with the output characteristics of the
alternator without neutral-point diodes, the output gradually increases
from midway by 10 to 15% at a normal rated alternator speed of approx.
5,000 rpm.

http://youronlinemechanic.com/alternator-with-neutral-point-voltage/

Here's a diagram of what the above link failed to clearly explain

http://autonopedia.org/renewable-energy/generators/alternator-secrets/

so somehow tapping neutral is good. I guess those two diodes bypass
current flowing int coils the wrong way or something? As to how speed
matters, I'm not following that.


If you consider that at any time 2 windings will be supplying one
polarity of current and the remaining winding the other polarity, you
can see the neutral point is going to move in the direction dictated by
the two windings. At higher currents, and higher frequencies, the
inductance of the winding causes an increasing voltage to appear at the
neutral point.

Some more info:-

http://tinyurl.com/kdcsayk

http://ece.ubm.ro/cjece/web/CJECE_VOL5_2012/3_Barz.pdf



Best regards,
Spehro Pefhany

Thank you for the information- also thanks to Mike Perkins-The
references were useful my background is in power systems so I have a
different view on 3rd harmonics.

Don Kelly
remove the cross to reply

Paul Hovnanian P.E.
Guest

Tue Aug 27, 2013 8:22 pm   



Mike Cook wrote:

Quote:
http://www.autoshop101.com/forms/alt_bwoh.pdf

has photos of an alternator with 4 connections for windings (each of 3
phases + common), and the 8 diode rectifier. But wiring diagrams show only
3 connections and 6 diodes.


You are referring to the diagram on page 3 of the above document?

Those are not the individual windings brought out of the alternator. The 6
winding leads are connected internally through the diode bridge and brought
out as two connections to the outside world. The B+ terminal and the
alternator frame ground. This is shown on pages 23 and 24.

Quote:
Where does the common winding terminal connect (there is a connection on
the rectifier plate)? Where do the other 2 diodes connect?


What isn't made clear in this document are the connections between the
windings, field and internal regulator. The regulator connections are
brought out as the IG, S, and L terminals (some alternators may have more
or fewer of these connections).

Quote:
I handled one of these disassembled units but didn't have time to ohm out
the connections.

Thanks.


--
Paul Hovnanian mailto:Paul_at_Hovnanian.com
------------------------------------------------------------------
Failure is not an option. It's standard equipment on this model.

Goto page Previous  1, 2

elektroda.net NewsGroups Forum Index - Electronics Equipment - Automotive alternator windings & rectifier

Ask a question - edaboard.com

Arabic versionBulgarian versionCatalan versionCzech versionDanish versionGerman versionGreek versionEnglish versionSpanish versionFinnish versionFrench versionHindi versionCroatian versionIndonesian versionItalian versionHebrew versionJapanese versionKorean versionLithuanian versionLatvian versionDutch versionNorwegian versionPolish versionPortuguese versionRomanian versionRussian versionSlovak versionSlovenian versionSerbian versionSwedish versionTagalog versionUkrainian versionVietnamese versionChinese version
RTV map EDAboard.com map News map EDAboard.eu map EDAboard.de map EDAboard.co.uk map