AC taps on car altrnator
altavoz
altavoz: Some one asked about the choke heater on a car
and got a response from rick Jones :
Rick Jones: The best way to run an electric
choke is from the alternator "AC" taps,
sometimes labeled as "stator", "phase" or "P" or "N" for neutral, or you
can open up the alternator and add on, these hooks to any of the stator
wires going to the rectifier of you can use the "Y" connection on wye
wound stators, this would be a neutral, but the result is around 8 volts
AC and the advantage of this is that the choke wont warm up if you left
the key on, it has to be running, and of course, the alternater has to
be working. Rick Jones, Toyota Master/ASE Master/L-1
altavoz: In a car , their are no AC taps on the alt' . Even tapping
into the stator will get you a DC voltage , it may have low or high
ripple , but it is DC . A Y wound alt has a center tap . It is 8 VDC .
If you tap one turn from the Y , it will be the same DC voltage , a
little
higher ripple , if you tap in one turn from a diode , you'll have a DC\
voltage with high ripple .
Rick has managed to convince some in the "autos.tech" NG that there is
an AC tap on a car alt .
David Lesher
>altavoz: In a car , their are no AC taps on the alt' . Even tapping
>into the stator will get you a DC voltage , it may have low or high
>ripple , but it is DC . A Y wound alt has a center tap . It is 8 VDC .
>If you tap one turn from the Y , it will be the same DC voltage , a
>little
>higher ripple , if you tap in one turn from a diode , you'll have a DC\
>voltage with high ripple .
> Rick has managed to convince some in the "autos.tech" NG that there is
>an AC tap on a car alt .
Errr... I'm REALLY interested in this alternator whose windings
deliver DC. Beside contravening everything my BEE classes taught me
about Maxwell, magnetics and transformers; if the windings deliver
DC... then Detroit has been wasting money putting diode trios
into each and every car they sell!
--
A host is a host from coast to coast.................wb8foz@nrk.com
& no one will talk to a host that's close........[v].(301) 56-LINUX
Unless the host (that isn't close).........................pob 1433
is busy, hung or dead....................................20915-1433
Nice address
>
>>altavoz: In a car , their are no AC taps on the alt' . Even tapping
>>into the stator will get you a DC voltage , it may have low or high
>>ripple , but it is DC . A Y wound alt has a center tap . It is 8 VDC .
>>If you tap one turn from the Y , it will be the same DC voltage , a
>>little
>>higher ripple , if you tap in one turn from a diode , you'll have a DC\
>>voltage with high ripple .
>> Rick has managed to convince some in the "autos.tech" NG that there is
>>an AC tap on a car alt .
Are we going in circles? A normal car alternator is a three phase AC
power generator with a rotating field, wired to a bridge rectifier.
Your meter might read +8 V because your meter can not follow the
changing pulse. The voltage must be in excess of +12 V or it will not
charge the battery.
Some have wanted to use the alternator as an AC power plant,
which is possible, but not practical.
If the diodes are removed the AC component is high enough to
run a power drill. I have seen this demonstrated. It is not 60 cycle.
Some alternators have a built in regulator, which might limit the
maximum voltage.
altavoz
>altavoz: In a car , their are no AC taps on the alt' . Even tapping
>into the stator will get you a DC voltage , it may have low or high
>ripple , but it is DC . A Y wound alt has a center tap . It is 8 VDC .
>If you tap one turn from the Y , it will be the same DC voltage , a
>little
>higher ripple , if you tap in one turn from a diode , you'll have a DC\
>voltage with high ripple .
> Rick has managed to convince some in the "autos.tech" NG that there is
>an AC tap on a car alt .
Errr... I'm REALLY interested in this alternator whose windings
deliver DC. Beside contravening everything my BEE classes taught me
about Maxwell, magnetics and transformers; if the windings deliver
DC... then Detroit has been wasting money putting diode trios
into each and every car they sell!
altavoz: The key words here are IN A CAR . A voltmeter placed
anywhere on the stator will show DC with ripple depending
on how far from the center of the winding .
Do you have that concept yet ? IN A CAR ....
James E. Thompson
wb8...@netcom.com (David Lesher) wrote:
>
>
>
>>altavoz: In a car , their are no AC taps on the alt' . Even tapping
>>into the stator will get you a DC voltage , it may have low or high
>>ripple , but it is DC . A Y wound alt has a center tap . It is 8 VDC .
>>If you tap one turn from the Y , it will be the same DC voltage , a
>>little
>>higher ripple , if you tap in one turn from a diode , you'll have a DC\
>>voltage with high ripple .
>> Rick has managed to convince some in the "autos.tech" NG that there is
>>an AC tap on a car alt .
>
>
>Errr... I'm REALLY interested in this alternator whose windings
>deliver DC. Beside contravening everything my BEE classes taught me
>about Maxwell, magnetics and transformers; if the windings deliver
>DC... then Detroit has been wasting money putting diode trios
>into each and every car they sell!
>--
>A host is a host from coast to coast.................wb8foz@nrk.com
>& no one will talk to a host that's close........[v].(301) 56-LINUX
>Unless the host (that isn't close).........................pob 1433
>is busy, hung or dead....................................20915-1433
An alternator has an rotating armature with DC in it (the field
current if you will). The output comes by way of a "Y" configured
stator, thus you can get 3-phase AC at the 3-points of the "Y". You
get DC at the alternator output because there is a 6-diode 3-phase
bridge rectifier between the "Y" and the A-terminal.
...Jim Thompson
% James E.Thompson, P.E. % mens %
% Analog Innovations, Inc. % et %
% Analog/Mixed-Signal ASIC's and Discrete Systems % manus %
% Phoenix, Arizona Voice: (602)460-2350 % Brass Rat %
% ana...@primenet.com Fax: (602)460-2142 % 1962 %
HEY, LOOK! IT'S NOT MY FAULT; IT'S SOME GUY NAMED "GENERAL PROTECTION".
(Ratbert, the Consultant, speaks, in Dilbert, by Scott Adams)
For proper E-mail replys remove "1" from E-mail address.
Terry Simonds
wb8...@netcom.com (David Lesher) wrote:
->Errr... I'm REALLY interested in this alternator whose windings
->deliver DC. Beside contravening everything my BEE classes taught me
->about Maxwell, magnetics and transformers; if the windings deliver
->DC... then Detroit has been wasting money putting diode trios
->into each and every car they sell!
I think what the original poster had in mind was that if you connect a
dc voltmeter to to any of the wires (except gnd) coming from an
alternator you will observe an upscale swing on the meter. The reason
this happens is that diodes, internal to the alternator, are
rectifying the 3-phase ac from the rotating machine.
If you look at any wire with an oscilloscope, you'll see essentially
dc with a lot of audio-frequency ripple riding on it (this is the
"whine" heard in some car radios when you rev up the engine).
If you were to run the alternator into a resistive load, you would
have some pretty nasty dc to contend with, for the alternator output
would not be filtered. However, connect the alternator to a storage
battery and, Voila! Relatively smooth, clean dc. The battery acts as a
very good filter by filling in the dips in the ripple waveform.
Getting back to the alternator whine for a minute... I have installed
many transceivers in automobiles and boats and have found that in the
majority of cases the whine has come from one or both of two sources:
a bad diode in the alternator or poor electrical connection between
the alternator "armature" line and the battery.
If you want a real eye-opener when you're experiencing some hard or
slow starts on your engine-cranking battery, but your hydrometer shows
a good battery, try the following (WARNING--Wear eye protection):
1. Connect a dc voltmeter with one probe on the battery post (pos
or neg) and the other proble on the clamp to the same post.
2. Have someone crank the engine and watch the meter during cranking.
I've seen as much as 2-3 volts between the post and the clamp! This
lousy connection may not show up under a low lighting or radio load as
anything significant. However, consider that this poor connection can
be thought of as a fixed resistor in series with the battery line.
Then apply some high-school physics and math and the formula V = I x
R, where the voltage (V) across the resistance (R) is equal to the
current (I) through the resistance multiplied by the resistance. I'd
guess that cranking a robust 4- or 6-cyl diesel that's cold would suck
200-300 amperes through the poor connection? You do the math and
you'll see it won't take must of a corrosion problem in the battery
clamps to cause a sluggish start.
Good grief, how did I get off on this subject?
73--Terry/WB4FXD in Ft. Lauderdale, FL
***Use this for reply: fsim...@icanect.net
Address in header is SPAM filter
RebeccaD
Terry Simonds wrote:
>
> wb8...@netcom.com (David Lesher) wrote:
>
> ->Errr... I'm REALLY interested in this alternator whose windings
> ->deliver DC. Beside contravening everything my BEE classes taught me
> ->about Maxwell, magnetics and transformers; if the windings deliver
> ->DC... then Detroit has been wasting money putting diode trios
> ->into each and every car they sell!
>
> I think what the original poster had in mind was that if you connect a
> dc voltmeter to to any of the wires (except gnd) coming from an
> alternator you will observe an upscale swing on the meter. The reason
> this happens is that diodes, internal to the alternator, are
> rectifying the 3-phase ac from the rotating machine.
>
> If you look at any wire with an oscilloscope, you'll see essentially
> dc with a lot of audio-frequency ripple riding on it (this is the
> "whine" heard in some car radios when you rev up the engine).
>
> If you were to run the alternator into a resistive load, you would
> have some pretty nasty dc to contend with, for the alternator output
> would not be filtered. However, connect the alternator to a storage
> battery and, Voila! Relatively smooth, clean dc. The battery acts as a
> very good filter by filling in the dips in the ripple waveform.
>
Has anybody ever used a 12 v field current on an automotive alternator
to get a 120 v output? I seem to recall this arrangement on a homemade
generator some years ago.
Nick Pine
>->I'm REALLY interested in this alternator whose windings deliver DC.
Would you kindly remove alt.solar.thermal from these postings?
Thanks,
Nick
Melissa & Jim
altavoz <alta...@mail.idt.net> wrote:
>altavoz: In a car , their are no AC taps on the alt' . Even tapping
>into the stator will get you a DC voltage , it may have low or high
>ripple , but it is DC . A Y wound alt has a center tap . It is 8 VDC .
>If you tap one turn from the Y , it will be the same DC voltage , a
>little
>higher ripple , if you tap in one turn from a diode , you'll have a DC\
>voltage with high ripple .
> Rick has managed to convince some in the "autos.tech" NG that there is
>an AC tap on a car alt .
I've never seen an alternator with an AC tap, but there certainly is
AC (3 phase, in fact) there. You would just need to connect between
any two points before the diodes.
I agree that if one of your two points is the car's chassis, then that
point is outside the rectifiers and the closest you can come to AC is
pulsating DC.
---------------------------------------------------------------------
Melissa Kepner Jim Adney
mgke...@facstaff.wisc.edu jra...@njackn.com
Laura Kepner-Adney
Madison, Wisconsin
---------------------------------------------------------------------
Neil Grigg
G'day atlavoz,
(Sorry to post this reply to so many NG's but I cannot tell what NG the oiginal
post came from - and I really hate how one message is cross posted to so many
other NGs)
On Fri, 23 May 1997 20:54:51 -0700, altavoz <alta...@mail.idt.net> wrote:
>> Rick has managed to convince some in the "autos.tech" NG that there is
>>an AC tap on a car alt .
>altavoz: The key words here are IN A CAR . A voltmeter placed
>anywhere on the stator will show DC with ripple depending
>on how far from the center of the winding .
>Do you have that concept yet ? IN A CAR ....
I'm sure others have sorta said this, but I have'nt seen their replies.
Do u understand basic ac theory?
If not, then say so, and I'll give u a quick lesson.
If yes, then u can give me a quick lesson on how u get dc from a rotating magnet
field (rotor) that is cutting a stationary winding (stator)?
--
Ta-ta,
Neil (Moe, Latrobe Valley, Gippsland, Victoria, Australia)
altavoz
altavoz: This question of alt's is bounded to a car and battery .
Terry does a good job of explaning it .
wb8...@netcom.com (David Lesher) wrote:
Errr... I'm REALLY interested in this alternator whose windings
deliver DC. Beside contravening everything my BEE classes taught me
about Maxwell, magnetics and transformers; if the windings deliver
DC... then Detroit has been wasting money putting diode trios
into each and every car they sell!
altavoz: POOR DAVE . WASTED HIS BEE MONEY ! Dave and i know Maxwells
equations but he has trouble knowing WHEN to use them.
Tell me Dave how tall can you stand on your sheep skins ?
Terry: I think what the original poster had in mind was that if you
connect a
dc voltmeter to to any of the wires (except gnd) coming from an
alternator you will observe an upscale swing on the meter. The reason
this happens is that diodes, internal to the alternator, are
rectifying the 3-phase ac from the rotating machine.
If you look at any wire with an oscilloscope, you'll see essentially
dc with a lot of audio-frequency ripple riding on it (this is the
"whine" heard in some car radios when you rev up the engine).
If you were to run the alternator into a resistive load, you would
have some pretty nasty dc to contend with, for the alternator output
would not be filtered. However, connect the alternator to a storage
battery and, Voila! Relatively smooth, clean dc. The battery acts as a
very good filter by filling in the dips in the ripple waveform.
73--KC7CC
altavoz
altavoz <alta...@mail.idt.net> wrote:
>altavoz: In a car , their are no AC taps on the alt' . Even tapping
>into the stator will get you a DC voltage , it may have low or high
>ripple , but it is DC . A Y wound alt has a center tap . It is 8 VDC .
>If you tap one turn from the Y , it will be the same DC voltage , a
>little
>higher ripple , if you tap in one turn from a diode , you'll have a DC\
>voltage with high ripple .
> Rick has managed to convince some in the "autos.tech" NG that there is
>an AC tap on a car alt .
I've never seen an alternator with an AC tap, but there certainly is
AC (3 phase, in fact) there. You would just need to connect between
any two points before the diodes.
I agree that if one of your two points is the car's chassis, then that
point is outside the rectifiers and the closest you can come to AC is
pulsating DC.
Melissa Kepner Jim Adney
mgke...@facstaff.wisc.edu jra...@njackn.com
Laura Kepner-Adney
Madison, Wisconsin
altavoz: PRECISELY ! When one uses a common point for his voltage
measurements , the stator will show DC with ripple , not AC .
altavoz
Has anybody ever used a 12 v field current on an automotive alternator
to get a 120 v output? I seem to recall this arrangement on a homemade
generator some years ago.
altavoz: Yes . You would expect at some output voltage , the
alt will give a higher power than at other voltages .
The automotive alternator seems to be wound for about 20-30 volts,
but can go to 120 vdc if the RPM is very high . Delta wound alt's
are a little lower volt at peak power .
If the alt can do 1000 watts , expect less at 120 vdc .
A SMPS would work to give the fld rotor it's 12 volt current.
David Lesher
>>altavoz: In a car , their are no AC taps on the alt' . Even tapping
.........................................................^^^^^^^^^^^^^
>>into the stator will get you a DC voltage , it may have low or high
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
>>ripple , but it is DC . A Y wound alt has a center tap . It is 8 VDC .
^^^^^^^^^^^^^^^^^^^^^^^^
>I agree that if one of your two points is the car's chassis, then that
>point is outside the rectifiers and the closest you can come to AC is
>pulsating DC.
> Melissa Kepner Jim Adney
> mgke...@facstaff.wisc.edu jra...@njackn.com
> Laura Kepner-Adney
> Madison, Wisconsin
>altavoz: PRECISELY ! When one uses a common point for his voltage
>measurements , the stator will show DC with ripple , not AC .
That depends on WHAT common point you choose to use.
But that is NOT what ?Mr.? altavoz so rudely claimed. Between
insults, he claimed 'tapping into the stator' will get you DC.
Well, that depends. It's a 3-phase alternator. (They are typically
Y-wound, but need not be.) If you tap off each end of any one
winding; or as the Y-wound diode trios do, from ends of two
windings, you get AC, same as any rotating machine [1].
Now, if you take one winding tap, and the chassis (pretty foolish --
why would you bother?), you'll get DC with AC ripple as Ms./Mr.
Kepner-Adney politely described.
[1] There is only one generator of (pure) DC ever invented. Since
?Mr.? altavoz feels an education is a waste, I'm sure he is aware
of, and can describe, that unique machine.
Hint: It's NOT a conventional "DC" generator. A stationary field
generator, such as pre-alternator cars used, generates AC in the
rotor and mechanically rectifies it in the commutator. The
unfiltered output is far from good DC.
Perry L. Vale
altavoz <alta...@mail.idt.net> wrote:
>>altavoz: In a car , their are no AC taps on the alt' . Even tapping
>>into the stator will get you a DC voltage , it may have low or high
>>ripple , but it is DC . A Y wound alt has a center tap . It is 8 VDC .
>>If you tap one turn from the Y , it will be the same DC voltage , a
>>little
>>higher ripple , if you tap in one turn from a diode , you'll have a DC\
>>voltage with high ripple .
>> Rick has managed to convince some in the "autos.tech" NG that there is
>>an AC tap on a car alt .
>Errr... I'm REALLY interested in this alternator whose windings
>deliver DC. Beside contravening everything my BEE classes taught me
>about Maxwell, magnetics and transformers; if the windings deliver
>DC... then Detroit has been wasting money putting diode trios
>into each and every car they sell!
>altavoz: The key words here are IN A CAR . A voltmeter placed
>anywhere on the stator will show DC with ripple depending
>on how far from the center of the winding .
>Do you have that concept yet ? IN A CAR ....
Years ago, I tapped the 3phase wye winding in a 100amp truck
alternator I had put in my car, fed it through a 3phase wye-wye
transformer to step it up to about 850-900 volts, and then rectified
and filtered it to feed the 750watt tube linear amp I was running at
the time on 10meters. As I recall, the low voltage primary on the
transformers used was a 12.6volt filament winding. I had to use a hand
throttle and lock the engine rpm at about 2000 to get a pretty steady
900 volts. There's my 2 cents....
73 de Perry N0MXJ
Mike
In article <3384CE...@mail.idt.net>, altavoz <alta...@mail.idt.net>
writes
>altavoz: Some one asked about the choke heater on a car
>and got a response from rick Jones :
>
>Rick Jones: The best way to run an electric
>choke is from the alternator "AC" taps,
>sometimes labeled as "stator", "phase" or "P" or "N" for neutral, or you
>can open up the alternator and add on, these hooks to any of the stator
>wires going to the rectifier of you can use the "Y" connection on wye
>wound stators, this would be a neutral, but the result is around 8 volts
>AC and the advantage of this is that the choke wont warm up if you left
>the key on, it has to be running, and of course, the alternater has to
>be working. Rick Jones, Toyota Master/ASE Master/L-1
>
>into the stator will get you a DC voltage , it may have low or high
>ripple , but it is DC . A Y wound alt has a center tap . It is 8 VDC .
>If you tap one turn from the Y , it will be the same DC voltage , a
>little
>higher ripple , if you tap in one turn from a diode , you'll have a DC\
>voltage with high ripple .
> Rick has managed to convince some in the "autos.tech" NG that there is
>an AC tap on a car alt .
You are correct. If, You were to measure between any arm of the stator
(star wound) and ground, you will measure D.C with a large ripple
voltage and 1/3 of the frequency of the ripple frequency across the
Battery.Why? because its still being rectified with respect to ground.
---
!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
! MI...@hengrove.demon.co.uk !
! !
! 10170...@compuserve.com !
! !
!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
Nick Pine
Perry L. Vale <pvale...@midusa.net> wrote:
>altavoz <alta...@mail.idt.net> wrote:
>
>>>altavoz: In a car , their are no AC taps on the alt'...
Please REMOVE alt.solar.thermal from this newsgroup distribution.
Thanks,
Nick
Date: Thu, 23 Feb 95 07:58:25 EST
Message-Id: <950223125...@nfs.ee.vill.edu>
Newsgroups: alt.config,alt.solar.thermal,alt.solar.thermal.ctl,control
Subject: cmsg newgroup alt.solar.thermal
Summary: newgroup for technical discussions of solar thermal energy
Followup-To: alt.solar.thermal
Control: newgroup alt.solar.thermal
Approved: ni...@ece.vill.edu
Organization: Villanova University
Keywords: solar thermal energy
alt.solar.thermal is intended to be a newsgroup for technical discussions
of practical low-temperature solar thermal energy collection and use.
It is NOT intended to be a place to discuss politics, photovoltaics,
laptop computers, solar space mirrors, envelope houses, Stirling engines,
solar refrigerators or air conditioning, cool tubes, heat pipes, wind
energy, wood energy, methane generation, perpetual motion, Nikola Tesla,
unseen forces, electromagnetic pollution, capturing free energy from power
lines or radio stations, nuclear waste or 600 mpg cars.
Nicholson L. Pine System design and consulting
Pine Associates, Ltd. (610) 489-0545
821 Collegeville Road Fax: (610) 489-7057
Collegeville, PA 19426 Email: ni...@ece.vill.edu
Melissa & Jim
altavoz <alta...@mail.idt.net> wrote:
>altavoz: The key words here are IN A CAR . A voltmeter placed
>anywhere on the stator will show DC with ripple depending
>on how far from the center of the winding .
>
>Do you have that concept yet ? IN A CAR ....
It's got nothing to do with where the alternator is located.
Everything to do with where you put the probes. If you put one of the
probes on the body of the alternator (or the chassis of the car) then
you are already outside of the diodes, and you will see their effect.
Jim
---------------------------------------------------------------------
Melissa Kepner Jim Adney
mgke...@facstaff.wisc.edu jra...@njackn.com
Laura Kepner-Adney
Madison, Wisconsin
---------------------------------------------------------------------
Chris
tsim...@icanect.net (Terry Simonds) wrote:
>I've seen as much as 2-3 volts between the post and the clamp! This
>lousy connection may not show up under a low lighting or radio load as
>anything significant. However, consider that this poor connection can
>be thought of as a fixed resistor in series with the battery line.
>Then apply some high-school physics and math and the formula V = I x
>R, where the voltage (V) across the resistance (R) is equal to the
>current (I) through the resistance multiplied by the resistance. I'd
>guess that cranking a robust 4- or 6-cyl diesel that's cold would suck
>200-300 amperes through the poor connection? You do the math and
>you'll see it won't take must of a corrosion problem in the battery
>clamps to cause a sluggish start.
>
I used to pour new posts on tractor batteries for customers who blew
the posts off the batteries in thier equipment.
>Good grief, how did I get off on this subject?
I think the original post must have had something to do with trying to
get 110V ac out of an automotive alternator. I have heard old timers
talk of doing it but having examined a typical externally regulated
alternator it isnt evident to me how it was done.
I am still wondering......
Chris
Chris
pvale...@midusa.net (Perry L. Vale) wrote:
>Years ago, I tapped the 3phase wye winding in a 100amp truck
>alternator I had put in my car, fed it through a 3phase wye-wye
>transformer to step it up to about 850-900 volts, and then rectified
>and filtered it to feed the 750watt tube linear amp I was running at
>the time on 10meters. As I recall, the low voltage primary on the
>transformers used was a 12.6volt filament winding. I had to use a hand
>throttle and lock the engine rpm at about 2000 to get a pretty steady
>900 volts. There's my 2 cents....
>
>73 de Perry N0MXJ
This would be a transformer designed for 60hz. I wonder what kind of
core losses were occurring. It should work as you found out to a
certain degree but i wonder if it would run my circular saw?
CHRIS
Nick Pine
Melissa & Jim <mgke...@facstaff.wisc.edu> wrote:
>It's got nothing to do with where the alternator is located.
Would you please remove this discussion from the alt.solar.thermal newsgroup,
which was intended to be for technical discussions of practical low-temperature
solar thermal energy collection and use?
Thanks,
Nick
David Lesher
chr...@istar.ca (Chris ) writes:
>tsim...@icanect.net (Terry Simonds) wrote:
You need to tap the stator winding before they get rectified.
That means cracking the case, soldering 2 wires, and reassembling
it. That gives you AC, not 60hz by any means, but AC.
David Lesher
chr...@istar.ca (Chris ) writes:
>pvale...@midusa.net (Perry L. Vale) wrote:
>>Years ago, I tapped the 3phase wye winding in a 100amp truck
>>alternator I had put in my car, fed it through a 3phase wye-wye
>>transformer to step it up to about 850-900 volts, and then rectified
>>and filtered it to feed the 750watt tube linear amp I was running at
>>the time on 10meters.
>This would be a transformer designed for 60hz. I wonder what kind of
>core losses were occurring. It should work as you found out to a
>certain degree but i wonder if it would run my circular saw?
Different questions, really. You can run 60Hz xfmers at 400 hz with
only slightly higher losses -- just don't try and run them at *lower*
frequencies. Older linear supplies (in electronic equipment) had
little problem, except the electrolitics offer had a higher ESR.
Most switcher supplies such as in PC's seem to have no heartburn at
all over 300-400 hz power. Why should they --THEY just make DC out
of it first thing...
Now, as for your saw. If it's a "universal" motor that will run on
AC/DC (does it have brushes?), then it may work. Its inductive
reactance may be too high. You could rectify the resulting
transformer-output voltage and use it.
If it is a bigger beast, with an induction motor.... forget it.
Its output speed is a function of its input frequency; even if it
COULD run at six times rated RPM...would you WANT to be near it?
The Man
There are alternators that do have a high voltage A.C. tap,
the voltage is about 100Vac or so, and is three-phase.
This is a specialized device used by Ford in the 70s, the
voltage was used to power rear window defroster elements, in these
older cars.
This is not the same as the stator connection on a normal
alternator, the stator provides about 8Vdc for older style voltage
regulators (not electronic).
There is no tap for an Ac voltage on a normal alternator. The
unit would have to be modified to produce an Ac voltage.
Eric Rice
The Man
David Lesher
chr...@istar.ca (Chris ) writes:
>I think the original post must have had something to do with trying to
>get 110V ac out of an automotive alternator. I have heard old timers
>talk of doing it but having examined a typical externally regulated
>alternator it isnt evident to me how it was done.
>I am still wondering......
Chris, it's not really that hard..
1) Tap one of the windings. [Yes, you need to make 2 connections,
not just one ;-]
2) Run that to a step-up transformer. I'd say ~7 to 1 turns ratio,
but some tests will be needed.
3) Remove the existing field regulation and load [to the battery]
connections. Plan on driving the field a mite harder.
You should be able to get 110v, but it's unlikely to be 60hz.
[That's a function on of engine speed.] Further, you'll not get
that much - say the alternator was rated at 60A; expect to get
maybe half of that 800 watts -- you are, after all, not using all
three phases.
Matthias Meerwein
mgke...@facstaff.wisc.edu (Melissa & Jim) wrote:
>I've never seen an alternator with an AC tap, but there certainly is
>AC (3 phase, in fact) there. You would just need to connect between
>any two points before the diodes.
Most Bosch alternators do have an AC tap (at least they had one some years
ago).
The purpose of this terminal (designated with the letter "W") is to provide
an AC signal for the purpose of RPM measurement in diesel engines. Remember
that, with a diesel engine, one cannot use the breaker point (or hall sensor)
signal (no ignition system present) for RPM sensing, so this signal was used
instead to provide the RPM meter with an engine speed proportional signal.
Of course this is a bit less accurate due to the non-zero belt slip, but the
accuracy is sufficient for the intended purpose.
For economical reasons, no different alternators for diesel and gas engines
were made, so they all had the "W" terminal, although it was left open in
non-dieses applications.
BTW: I would rather not draw power from this terminal, as the alternator is
not designed to operate with an imbalance in the load on its three phases.
Greetings
Matthias
Matthias Meerwein
altavoz
David Lesher
chr...@istar.ca (Chris ) writes:
>I think the original post must have had something to do with trying to
>get 110V ac out of an automotive alternator. I have heard old timers
>talk of doing it but having examined a typical externally regulated
>alternator it isnt evident to me how it was done.
>I am still wondering......
Chris, it's not really that hard..
1) Tap one of the windings. [Yes, you need to make 2 connections,
not just one ;-]
2) Run that to a step-up transformer. I'd say ~7 to 1 turns ratio,
but some tests will be needed.
3) Remove the existing field regulation and load [to the battery]
connections. Plan on driving the field a mite harder.
You should be able to get 110v, but it's unlikely to be 60hz.
[That's a function on of engine speed.] Further, you'll not get
that much - say the alternator was rated at 60A; expect to get
maybe half of that 800 watts -- you are, after all, not using all
three phases. Dave
altavoz: You are serious , aren't you Dave ?
First , you wont get close to 800 watts with one winding , you'll
get barely 20 watts cause of the one winding and the transformer
losses .
But most important is nobody does it that convoluted way .
They put 14 vdc at the rotor and a 115 VDC load at the output
and rev the engine up to 3000 RPM .
An alt will put out 115 vdc at high RPM if it's fld gets 14 vdc .
Jose T. Conto
Somebody wrote:
> >I think the original post must have had something to do with trying to
> >get 110V ac out of an automotive alternator. I have heard old timers
> >talk of doing it but having examined a typical externally regulated
> >alternator it isnt evident to me how it was done.
> >I am still wondering......
Forget about tapping AC from the alternator.
If you need AC 60 Hz., connect a DC/AC convertor (solid state of course)
ready available in the market today.
The advantages are: no messing with your alternator, stable AC output, no
need to 'lock' your rpm's and using two DC power sources, your car
battery(around 500W ?) and its alternator (another 800W ?), plus others...
Match the size of the DC/AC convertor to your load+ a safety margin
(+20%.) Allow your battery to recharge frequently.
Connect the DC/AC convertor input to the battery terminals and its AC
output to your AC load. Done.
Jack Stands.
I think I get the story here it seems ALTAVOZ is one of those people who
persistently try to convince the world black is white or hot is cold.
You will never do it ALTAVOZ.
--
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mail from site only, email address invalid
altavoz <alta...@mail.idt.net> wrote in article
<338852...@mail.idt.net>...
> altavoz: This question of alt's is bounded to a car and battery .
> Terry does a good job of explaning it .
>
> wb8...@netcom.com (David Lesher) wrote:
>
> Errr... I'm REALLY interested in this alternator whose windings
> deliver DC. Beside contravening everything my BEE classes taught me
> about Maxwell, magnetics and transformers; if the windings deliver
> DC... then Detroit has been wasting money putting diode trios
> into each and every car they sell!
>
> I've seen as much as 2-3 volts between the post and the clamp! This
> lousy connection may not show up under a low lighting or radio load as
> anything significant. However, consider that this poor connection can
> be thought of as a fixed resistor in series with the battery line.
> Then apply some high-school physics and math and the formula V = I x
> R, where the voltage (V) across the resistance (R) is equal to the
> current (I) through the resistance multiplied by the resistance. I'd
> guess that cranking a robust 4- or 6-cyl diesel that's cold would suck
> 200-300 amperes through the poor connection? You do the math and
> you'll see it won't take must of a corrosion problem in the battery
> clamps to cause a sluggish start.
>
> Good grief, how did I get off on this subject?
>
>
vjni...@ionet.net
In <338AF6...@mail.idt.net>, altavoz <alta...@mail.idt.net> writes:
>David Lesher
>chr...@istar.ca (Chris ) writes:
>
>
>>get 110V ac out of an automotive alternator. I have heard old timers
>>talk of doing it but having examined a typical externally regulated
>>alternator it isnt evident to me how it was done.
>>I am still wondering......
>
>
>1) Tap one of the windings. [Yes, you need to make 2 connections,
>not just one ;-]
>
>2) Run that to a step-up transformer. I'd say ~7 to 1 turns ratio,
>but some tests will be needed.
>
>3) Remove the existing field regulation and load [to the battery]
>connections. Plan on driving the field a mite harder.
>
>You should be able to get 110v, but it's unlikely to be 60hz.
>[That's a function on of engine speed.] Further, you'll not get
>that much - say the alternator was rated at 60A; expect to get
>maybe half of that 800 watts -- you are, after all, not using all
>three phases. Dave
>
>
>altavoz: You are serious , aren't you Dave ?
>First , you wont get close to 800 watts with one winding , you'll
>get barely 20 watts cause of the one winding and the transformer
>losses .
> But most important is nobody does it that convoluted way .
>They put 14 vdc at the rotor and a 115 VDC load at the output
>and rev the engine up to 3000 RPM .
> An alt will put out 115 vdc at high RPM if it's fld gets 14 vdc .
There was a Co. in Okla City area that made a unit to attach to your altnator and
get 120 volts. I sold quite a few of these units to utility crews so they could run
their large drills when they installed poles. any serial motor can run beyond 60
hz.
V.J.
David Lesher
vjni...@ionet.net writes:
>There was a Co. in Okla City area that made a unit to attach to your altnator and
>get 120 volts. I sold quite a few of these units to utility crews so they could run
>their large drills when they installed poles. any serial motor can run beyond 60
>hz.
True. So-called "Universal motors" with brushes can run on DC, or
AC. Problems can result with higher frequencies as the inductive
reactance goes up, limiting the current.
As for the suggestion to just swamp the field and get 120vdc out,
a) the previous poster was seeking AC, not DC.
b) This assumes the diode trio will have a high enough PIV to not
self-destruct at 120v vice its usual 15. I'd think that was a safe
bet, but Detroit is very skilled at shaving the last peso off the
cost of parts, and who's to say they did not find diodes rated at
50PIV at a better price?
The advantage of tapping the windings is you really have a hard time
doing any damage. If you short the winding out, the alternator just
goes into saturation. (The belt may well slip, or the engine
stall...). I've not yet damaged a stator winding, but then, I was
never trying to....
philip de cadenet
In article <5makn2$b...@vu-vlsi.ee.vill.edu>, Nick Pine <nick@vu-
vlsi.ee.vill.edu> writes
--
philip de cadenet
altavoz
David Lesher
it's not really that hard..
1) Tap one of the windings. [Yes, you need to make 2 connections,
not just one ;-]
2) Run that to a step-up transformer. I'd say ~7 to 1 turns ratio,
but some tests will be needed.
3) Remove the existing field regulation and load [to the battery]
connections. Plan on driving the field a mite harder.
You should be able to get 110v, but it's unlikely to be 60hz.
[That's a function on of engine speed.] Further, you'll not get
that much - say the alternator was rated at 60A; expect to get
maybe half of that 800 watts -- you are, after all, not using all
three phases. Dave
altavoz: You are serious , aren't you Dave ?
First , you wont get close to 800 watts with one winding , you'll
get barely 200 watts cause of the one winding and the transformer
losses .
But most important is nobody does it that convoluted way .
They put 14 vdc at the rotor and a 115 VDC load at the output
and rev the engine up to 3000 RPM .
An alt will put out 115 vdc at high RPM if it's fld gets 14 vdc/3 amps
.
V.J. says: There was a Co. in Okla City area that made a unit to attach
to your altnator and
get 120 volts. I sold quite a few of these units to utility crews so
they could run
their large drills when they installed poles. any serial motor can run
beyond 60
hz. V.J.
altavoz: Serial motors will see 115 VDC on a car alt , not AC .
I saw a stick welder using an alt . The fld was run at 80 vdc but
dropped to
14 volts with a huge resistor . This ballasts the welder ( as the weld
volt drops the alt output drops . MIG needs the opposite . It uses 20
vdc
with good regulation . If you have a few 115vac motors on the shelf ,
and
with rebuilt 60 amp alts at $25 , you'll do a MIG cheaper . But it is
heavy .
Peter D. Engels
In article <5mv3hf$f...@baygull.rtd.com>, d...@rtd.com (Don Yuniskis) wrote:
>Do you know that ^^^^^^^ for a **FACT**? The automakers use
>all sorts of oddball stuff that defies the rest of the
>industry. How many *germanium* devices do you think are
>sold in the "normal" industry? Yet, an auto supplier can
>(and *have*!) exploit that technology to squeeze a few
>extra bits of "performance" out of a design.
>
>When you're dealing with **huge** numbers, the economies of scale
>can seriously distort your sense of "reality". I know when I've
>done 10K quantity designs, the pricing becomes *obscene*! And,
>you don't hesitate to ask for a "special" that will solve two
>problems with one device, etc.
Who still makes germanium devices? They've been unavailable for twenty years.
--
Pete
altavoz
altavoz: This thread started cause the poor fellas in alt.autos.tech
can't figure AC from DC .
I said there are no AC taps on a car alternator , and they went
ballistic, menstral . Then they started saying even crazier things
like u must accurately measure the battery leak/drain when electrics
are turned off . +/- 30% should do when testing for battery drain !
If my alt diodes or radio or clock is draining .001 or .010 amp
who cares ! It's when it gets to .1 that i will need to fix it , same
with the trouble shooting , anything that will indicate +/- 30%
accuracy will do . Like a 4 1/2 digit panel meter from Hosfelt for
$18 using the cars wiring as the shunt to test for leaks .
I said if one has not a meter , just jump a wire from a headlamp
to the big stud on the alternator output to check for a bad wire
to battery , and they howled at that one ! They said you can't tell
by the headlamps brightness , how good the wire is !
WRONG ! If the charge wire from battery to alt is a high resistance
you'll lose a few volts , that same wire will drop the brightness
on your headlamps !
Remove batt from car and hook a cheap battery charger to your elect'
system and you can use a clamp-on ammeter to finds current drains .
They couldn't figure that one either !
BTW , where can i get LM2907 , Hosfelt said they did but were wrong.
BG Micro was said to have but my email from them denied this .
LM2917 will also work .
I'm making automotive instruments like tach,
speedo . I have coolant temp gages and voltmeters designed , ask me
about them . My voltmeter design doesn't use a negative supply . It
uses a 7106 with a LM431 to clamp it at 8.000 vdc ,then the com pin
is held at 5.2 vdc and the -in is held to 4.48vdc and the battery
voltage see's a 10:1 divider to the com pin ( 5.2vdc)
So if battery is at 10 vdc , mid of divider is 5.68vdc .
and the ref is at 1.000vdc .
Also have a short basic pgm to do resistance and skin effect .
Steve Weingart
In article <33958C...@mail.idt.net>, alta...@mail.idt.net wrote:
>
>BTW , where can i get LM2907 , Hosfelt said they did but were wrong.
>BG Micro was said to have but my email from them denied this .
>LM2917 will also work .
Try DigiKey 1 800-344-4539 LM2907N-ND $3.60 ea in 1-zies, they usually have
everything in the catalog in stock. They list the 2917 too.
I use them for components all the time when my regular distributors don't
carry a particular manufacturer's line, Hosfelt is great, but I use them more
for surplus and odd stuff, James is in the middle.
Steve
Jarrod Driscoll
Hello ,
My name is Jarrod Driscoll and I was wondering if anyone out there
could help me, I would like some schematics on how to connect 8 lead
screens togethers. Four switches one for 2 lead screens when you press a
switch the lead screen is incremented by 1.(max value is 99 for screen
when that has been reached return back to zero). Also a fifth switch that
when the time is set to what ever value you want you press it and the time
starts to count down.
switches
1 + 2 + 3 + 4 +
___________ ____________ ___________ ___________
| 1 | 2 | | 1 | 1 | | 2 | 4 | | 3 | 2 |
|____|____| |_____|____| |____|____| |____|____|
day hrs min sec
switch 5 +
All the way down to 00 00 00 00.
If any one could offer any schematics , kits, books etc it would be very
helpful.
Thanks in advance.
JD
donc
Radio Shack sells them.
donc