I'm thinking that all else left alone, it probably doesn't matter which
way the shaft of an automobile alternator is rotated since the machine
produces ac which is then rectified to create a polarized dc output.

Am I right about that?

The question came up just now when eldest son and I were kibitzing about
this week's "Car Talk" puzzler:

http://www.cartalk.com/content/puzzl...918/index.html

Thanks guys,

Jeff

--
Jeffry Wisnia
(W1BSV + Brass Rat '57 EE)
The speed of light is 1.8*10^12 furlongs per fortnight.

jeff_wisnia wrote:

I'm thinking that all else left alone, it probably doesn't matter which
way the shaft of an automobile alternator is rotated since the machine
produces ac which is then rectified to create a polarized dc output.

Am I right about that?

The only issue should be the cooling fan. If it spins the wrong way, it
won't cool anything.

jeff_wisnia writes:


I'm thinking that all else left alone, it probably doesn't matter which
way the shaft of an automobile alternator is rotated since the machine
produces ac which is then rectified to create a polarized dc output.

Am I right about that?

The wear on the slip ring brushes may be different.

And I agree with your thinking as to the Puzzler.
--
A host is a host from coast to
& 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

jeff_wisnia writes:

I'm thinking that all else left alone, it probably doesn't matter
which way the shaft of an automobile alternator is rotated since the
machine produces ac which is then rectified to create a polarized dc
output.

Am I right about that?

The question came up just now when eldest son and I were kibitzing
about this week's "Car Talk" puzzler:

http://www.cartalk.com/content/puzzl...918/index.html

My drill is reversible, so it doesn't really matter anyway...

Joe Pfeiffer wrote:
jeff_wisnia writes:


I'm thinking that all else left alone, it probably doesn't matter
which way the shaft of an automobile alternator is rotated since the
machine produces ac which is then rectified to create a polarized dc
output.

Am I right about that?

The question came up just now when eldest son and I were kibitzing
about this week's "Car Talk" puzzler:

http://www.cartalk.com/content/puzzl...918/index.html


My drill is reversible, so it doesn't really matter anyway...


And all my 120 volt drills turn only CW. (That tells ya
how olde they (and I) am. G

Son just pinged me to say that if you ran the alternator belt over the
alternator pulley and then over the drill chuck you could point the
drill in the appropriate direction. That may be the answer the Car Talk
guys are looking for, as it's not likely there'd be enough room under
the hood to connect the drill through a socket directly to the
alternator shaft nut.

But, you could always unmount the alternator and.......

Jeff

--
Jeffry Wisnia
(W1BSV + Brass Rat '57 EE)
The speed of light is 1.8*10^12 furlongs per fortnight.

"jeff_wisnia" wrote in message
eonecommunications...
Joe Pfeiffer wrote:
jeff_wisnia writes:


I'm thinking that all else left alone, it probably doesn't matter
which way the shaft of an automobile alternator is rotated since the
machine produces ac which is then rectified to create a polarized dc
output.

Am I right about that?

The question came up just now when eldest son and I were kibitzing
about this week's "Car Talk" puzzler:

http://www.cartalk.com/content/puzzl...918/index.html


My drill is reversible, so it doesn't really matter anyway...


And all my 120 volt drills turn only CW. (That tells ya
how olde they (and I) am. G

Son just pinged me to say that if you ran the alternator belt over the
alternator pulley and then over the drill chuck you could point the drill
in the appropriate direction. That may be the answer the Car Talk guys are
looking for, as it's not likely there'd be enough room under the hood to
connect the drill through a socket directly to the alternator shaft nut.

But, you could always unmount the alternator and.......

Jeff

--
Jeffry Wisnia
(W1BSV + Brass Rat '57 EE)
The speed of light is 1.8*10^12 furlongs per fortnight.

I may be splitting hairs here, doesn't the battery have to have a little bit
of charge in order for the alsternator to be excited enought to generate?

jeff_wisnia wrote:

Joe Pfeiffer wrote:
jeff_wisnia writes:


I'm thinking that all else left alone, it probably doesn't matter
which way the shaft of an automobile alternator is rotated since the
machine produces ac which is then rectified to create a polarized dc
output.

Am I right about that?

The question came up just now when eldest son and I were kibitzing
about this week's "Car Talk" puzzler:

http://www.cartalk.com/content/puzzl...918/index.html


My drill is reversible, so it doesn't really matter anyway...

And all my 120 volt drills turn only CW. (That tells ya
how olde they (and I) am. G

Son just pinged me to say that if you ran the alternator belt over the
alternator pulley and then over the drill chuck you could point the
drill in the appropriate direction. That may be the answer the Car Talk
guys are looking for, as it's not likely there'd be enough room under
the hood to connect the drill through a socket directly to the
alternator shaft nut.

But, you could always unmount the alternator and.......

I wonder if hat's the correct approach. In my cars, the alternator
pulley ratio apears to be at least 3:1. So at idle, the alternator is
spinning at around 2400 RPM. My drill won't do anywhere near that speed.
And running the belt over the chuck will turn the alternator pulley
slower than the drill.

I'd just take the extension cord and/or jumper cables and wire the
generator in series with the alternator output. The alternator diodes
will rectify the AC. Then, throttle the generator up slowly. At a low
RPM, its voltage output will be low enough to charge the battery.

--
Paul Hovnanian
------------------------------------------------------------------
Porsche 928: 0 to c in 2.125 years, 2.435 light-years per mile^3 of gas

jeff_wisnia writes:

My drill is reversible, so it doesn't really matter anyway...


And all my 120 volt drills turn only CW. (That tells ya
how olde they (and I) am. G

Son just pinged me to say that if you ran the alternator belt over the
alternator pulley and then over the drill chuck you could point the
drill in the appropriate direction. That may be the answer the Car Talk
guys are looking for, as it's not likely there'd be enough room under
the hood to connect the drill through a socket directly to the
alternator shaft nut.

But, you could always unmount the alternator and.......


My answer is first look for a DC output from the generator. Many
have them.

Either direction will do; with the hood open and the engine
off the generator will be in a far cooler enviroment.

I wonder how hard you can push it anyhow. A 100A car alternator
is outputting ~1.5KW. [15v*100A] It needs say 2KW in to deliver
that. That means the drill would need to produce 2KW. It would
draw say 2600 watts. Can YOUR drill produce that? For how long?
(I think it more likely you can get 600 watts ergo 20A out.)

So I think it fair to say that while you can spin the alternator
and get some charge out of it; it's going to take you a while.

The other question is how to connect it up. Given we have a roll of
duct tape... wrap the pulley and the chuck in same; and use friction
drive? If it's a flat belt, you could drive it from the chuck...maybe.



--
A host is a host from coast to
& 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

"Nutz" writes:


I may be splitting hairs here, doesn't the battery have to have a little bit
of charge in order for the alsternator to be excited enought to generate?

Maybe. But often the soft iron contains enough flux to self-excite. And a
""dead"" battery isn't usually. Turn off the headlights, wait 10 minutes,
and you'll likely get several volts out...

--
A host is a host from coast to
& 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

On Mon, 04 May 2009 16:46:10 -0400, the infamous jeff_wisnia
scrawled the following:


I'm thinking that all else left alone, it probably doesn't matter which
way the shaft of an automobile alternator is rotated since the machine
produces ac which is then rectified to create a polarized dc output.

Am I right about that?

Electrically, you're probably right. But the brushes I've seen during
rebuilds of most brands (in my previous life) were usually situated to
run in one direction only and they'd self-destruct in minutes if run
the opposite direction.


The question came up just now when eldest son and I were kibitzing about
this week's "Car Talk" puzzler:

http://www.cartalk.com/content/puzzl...918/index.html

"Some kind of builder" wasn't very bright, was he?

I'd run the genset to power up the drill to turn the alternator to
charge the battery, even if I had to drill a hole through the radiator
support and/or grille to do it with a branch extension and the duct
tape.

--
The scientific theory I like best is that the rings of Saturn
are composed entirely of lost airline luggage.
--Mark Russell

"Nutz" writes:

I may be splitting hairs here, doesn't the battery have to have a little bit
of charge in order for the alsternator to be excited enought to generate?

You don't have enough power to turn the engine over (and will refer to
the battery as "dead") a long, long time before the juice is too low to
run the alternator.

The part of the problem I'm wondering about is getting the belt back on,
and tight enough to turn the alternator, with the engine running. Or
else you better live pretty close..

On Tue, 5 May 2009 10:03:41 +0800, the infamous "Nutz"
scrawled the following:

I may be splitting hairs here, doesn't the battery have to have a little bit
of charge in order for the alsternator to be excited enought to generate?

It would. Lead acids tend to rebuild naturally after the load is
removed, and lights left on would probably only pulled it down to 8v
or so, plenty for excitation of the silicon bits.

--
The scientific theory I like best is that the rings of Saturn
are composed entirely of lost airline luggage.
--Mark Russell

Joe Pfeiffer writes:


The part of the problem I'm wondering about is getting the belt back on,
and tight enough to turn the alternator, with the engine running. Or
else you better live pretty close..

Never happen.... Charge battery; replace belt, and hope it will start.
If not, yank belt, and charge 3x as long, try again.

I've tried to think up a belt-unloading scheme using the extra-virgin
olive oil, to no success....

I might UNPLUG the alternator while cranking; to remove that load from
the system...





--
A host is a host from coast to
& 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

David Lesher wrote:

Joe Pfeiffer writes:

The part of the problem I'm wondering about is getting the belt back on,
and tight enough to turn the alternator, with the engine running. Or
else you better live pretty close..

Never happen.... Charge battery; replace belt, and hope it will start.
If not, yank belt, and charge 3x as long, try again.

I've tried to think up a belt-unloading scheme using the extra-virgin
olive oil, to no success....

I might UNPLUG the alternator while cranking; to remove that load from
the system...


What load? The alternator isn't producing enough voltage while
cranking, to have usable output. The voltage has to equal or exceed the
battery voltage before it supplies any current.


--
You can't have a sense of humor, if you have no sense!

On Mon, 04 May 2009 16:46:10 -0400, jeff_wisnia
wrote:


I'm thinking that all else left alone, it probably doesn't matter which
way the shaft of an automobile alternator is rotated since the machine
produces ac which is then rectified to create a polarized dc output.

Am I right about that?

The question came up just now when eldest son and I were kibitzing about
this week's "Car Talk" puzzler:

http://www.cartalk.com/content/puzzl...918/index.html

Thanks guys,

Jeff

So he's gonna build a cabin with an electric drill and a socket
wrench? Must be an erector set scaled up, or maybe a metal pole
building. Not what I visualize when I think "cabin", but these are
modern times.

Joe

On Tue, 5 May 2009 06:06:59 +0000 (UTC), the infamous David Lesher
scrawled the following:

Joe Pfeiffer writes:


The part of the problem I'm wondering about is getting the belt back on,
and tight enough to turn the alternator, with the engine running. Or
else you better live pretty close..

Uh, Joe, with a charged battery, you can stop and start the engine at
will. There is no need to play around moving fan blades. Hmm, I hope
you're not a TEACHER at nmsu... heh heh heh


Never happen.... Charge battery; replace belt, and hope it will start.
If not, yank belt, and charge 3x as long, try again.

Oh, no. Charge battery, start engine, stop engine, replace belt, start
engine, drive home. Otherwise, charge longer and repeat above.

Oh, and tell that idiot who left his lights on to put the _fuse_ back
in so his warning buzzer actually warns him next time, eh?


I've tried to think up a belt-unloading scheme using the extra-virgin
olive oil, to no success....

That might have been a spoof item to take your mind off the real fix.


I might UNPLUG the alternator while cranking; to remove that load from
the system...

Huh? If you did that, it wouldn't be charging the battery.

--
The scientific theory I like best is that the rings of Saturn
are composed entirely of lost airline luggage.
--Mark Russell

On Tue, 05 May 2009 09:12:42 -0400, the infamous Joe
scrawled the following:

On Mon, 04 May 2009 16:46:10 -0400, jeff_wisnia
wrote:


I'm thinking that all else left alone, it probably doesn't matter which
way the shaft of an automobile alternator is rotated since the machine
produces ac which is then rectified to create a polarized dc output.

Am I right about that?

The question came up just now when eldest son and I were kibitzing about
this week's "Car Talk" puzzler:

http://www.cartalk.com/content/puzzl...918/index.html

Thanks guys,

Jeff

So he's gonna build a cabin with an electric drill and a socket
wrench?

They forgot to mention his hammah, nailbag, and handsaw.


Must be an erector set scaled up, or maybe a metal pole
building. Not what I visualize when I think "cabin", but these are
modern times.

Look what they refer to as cabins he
http://www.precisioncraft.com/loghom...k/Caribou.html
http://www.precisioncraft.com/loghom...n/Targhee.html
http://imaginactive.typepad.com/phot...log_home_2.jpg
http://www.cedar-log-homes.com/log-home-pictures.htm

Disgusting, isn't it?

--
The scientific theory I like best is that the rings of Saturn
are composed entirely of lost airline luggage.
--Mark Russell

Larry Jaques writes:

On Tue, 5 May 2009 06:06:59 +0000 (UTC), the infamous David Lesher
scrawled the following:

Joe Pfeiffer writes:


The part of the problem I'm wondering about is getting the belt back on,
and tight enough to turn the alternator, with the engine running. Or
else you better live pretty close..

Uh, Joe, with a charged battery, you can stop and start the engine at
will. There is no need to play around moving fan blades. Hmm, I hope
you're not a TEACHER at nmsu... heh heh heh

I wasn't anticipating standing there with the drill long enough to fully
charge the battery, just long enough to get the engine to turn over.
Yeah, leaving it there long enough to really charge would do it...

I am a professor; you'd need to ask my students whether I'm a teacher

Paul Hovnanian P.E. wrote:
jeff_wisnia wrote:

Joe Pfeiffer wrote:

jeff_wisnia writes:



I'm thinking that all else left alone, it probably doesn't matter
which way the shaft of an automobile alternator is rotated since the
machine produces ac which is then rectified to create a polarized dc
output.

Am I right about that?

The question came up just now when eldest son and I were kibitzing
about this week's "Car Talk" puzzler:

http://www.cartalk.com/content/puzzl...918/index.html


My drill is reversible, so it doesn't really matter anyway...

And all my 120 volt drills turn only CW. (That tells ya
how olde they (and I) am. G

Son just pinged me to say that if you ran the alternator belt over the
alternator pulley and then over the drill chuck you could point the
drill in the appropriate direction. That may be the answer the Car Talk
guys are looking for, as it's not likely there'd be enough room under
the hood to connect the drill through a socket directly to the
alternator shaft nut.

But, you could always unmount the alternator and.......


I wonder if hat's the correct approach. In my cars, the alternator
pulley ratio apears to be at least 3:1. So at idle, the alternator is
spinning at around 2400 RPM. My drill won't do anywhere near that speed.
And running the belt over the chuck will turn the alternator pulley
slower than the drill.

That's what I said to my son, but his immediate reply was, "So...wrap
that whole roll of duct tape around the drill chuck to increase its
diameter."

I'd just take the extension cord and/or jumper cables and wire the
generator in series with the alternator output. The alternator diodes
will rectify the AC. Then, throttle the generator up slowly. At a low
RPM, its voltage output will be low enough to charge the battery.


Yeah, that should work too, and I'd expect the alternator diodes would
have a high enough reverse breakdown rating to be able to stand someone
doing that, but what if I'm wrong??? G

Jeff

--
Jeffry Wisnia
(W1BSV + Brass Rat '57 EE)
The speed of light is 1.8*10^12 furlongs per fortnight.

On Mon, 04 May 2009 16:46:10 -0400, jeff_wisnia
wrote:


I'm thinking that all else left alone, it probably doesn't matter which
way the shaft of an automobile alternator is rotated since the machine
produces ac which is then rectified to create a polarized dc output.

Am I right about that?

The question came up just now when eldest son and I were kibitzing about
this week's "Car Talk" puzzler:

http://www.cartalk.com/content/puzzl...918/index.html

Thanks guys,

Jeff

If that is the current puzzler it has been recycled (not
like Ray would do something like that

The answer as I remember it was to use the generator to run
the drill to turn the alternator. I think they slipped the
belt off and looped it over the drill chuck.

As normal, I doubt if anyone actually tried to do this, but
in theory it should work, eventually...

--
Leon Fisk
Grand Rapids MI/Zone 5b
Remove no.spam for email

Larry Jaques writes:


Never happen.... Charge battery; replace belt, and hope it will start.
If not, yank belt, and charge 3x as long, try again.

Oh, no. Charge battery, start engine, stop engine, replace belt, start
engine, drive home. Otherwise, charge longer and repeat above.

You want to charge only long enough to start the engine once. Your drill
will likely be junk, your hand burnt, and your arm sore by then.



--
A host is a host from coast to
& 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

1.I don't think the drill would get you any significant output. The
diameter of the drill chuck is only 1 1/2" or so. The vehicle's
crankshast pulley is a LOT bigger and the car engine would have to be
running at 400 or 500 rpms or so to do the job.
Maybe the use for the duct tape is to wrap around the chuck until it
gets big enough to do the job. But I think that would take several rolls.

2. If I was in that situation, I'd consider taking the alternator (or
something else in the vacinity) apart to get a diode. Then I'd slow the
generator down a lot and use it to directly, (now outputing a much lower
voltage, half wave rectified) charge the battery. The duct tape could
be used to keep me from getting zapped. I think.

3.On the other hand, depending on the weather and the voltage the of
battery pack in the "radio" one might be able to use its batteries to
trickle charge the car for one start. If the "radio" was one of those
contractors models, it might take a 12, 18 or even higher voltage plug
in battery pack.

4.Okay---- Here it is: The "radio" has a built in charger for it's own
battery. Just plug the thing in to the generator, and with a little
judicious rewiring, use that charger to bring the car's battery back to
life. Pour the olive oil out around the car, so wild animals will slip
and fall down before they can attack you while you are getting things going.

Pete Stanaitis

David Lesher wrote:

You want to charge only long enough to start the engine once. Your drill
will likely be junk, your hand burnt, and your arm sore by then.


Assuming a fair sized drill, 1/2 hp = 373 watts. 13.6v nominal charging = 373/13.6 = 27A
No figuring conversion efficiency at each level.


Yup, that drill is going to be a bit warm and the arm sore. Maybe the olive oil is to
lube the bushings in the cheap walmart drill you are using.

Wes

"Michael A. Terrell" writes:


I might UNPLUG the alternator while cranking; to remove that load from
the system...


What load? The alternator isn't producing enough voltage while
cranking, to have usable output. The voltage has to equal or exceed the
battery voltage before it supplies any current.

And the battery voltage at this point is ..? At some point the curves
cross. But when?

Unplugging the field makes the load nil. Once the engine is going, plug
it back in. It will go to full field excitation, and provide as much
current as it can at idle.... and engine load.


--
A host is a host from coast to
& 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

On May 4, 3:46*pm, jeff_wisnia wrote:
I'm thinking that all else left alone, it probably doesn't matter which
way the shaft of an automobile alternator is rotated since the machine
produces ac which is then rectified to create a polarized dc output.

Am I right about that?

The question came up just now when eldest son and I were kibitzing about
this week's "Car Talk" puzzler:

http://www.cartalk.com/content/puzzl...918/index.html

Thanks guys,

Jeff

--
Jeffry Wisnia
(W1BSV + Brass Rat '57 EE)
The speed of light is 1.8*10^12 furlongs per fortnight.

A former poster on this group....
Told a tale of parking his car Many miles into the wilderness, and
leaving on foot for several months.
Upon his return, the battery would be dead, and a few ( 50?) miles
from any passing help.
What he used was an old propane tank, and AIR (80's style smog) pump,
and some lines.

He'd fill the old propane tank with water, throw it on the fire, and
the line ran to the old AIR pump, which was rigged to run backwards
and act as a "turbine" spinning the alternaor and charging the battery
to allow his escape in the fall.

That was his story. It was Just crazy enough to work.. Maybe.

David Lesher wrote:

"Michael A. Terrell" writes:

I might UNPLUG the alternator while cranking; to remove that load from
the system...

What load? The alternator isn't producing enough voltage while
cranking, to have usable output. The voltage has to equal or exceed the
battery voltage before it supplies any current.

And the battery voltage at this point is ..? At some point the curves
cross. But when?

Unplugging the field makes the load nil. Once the engine is going, plug
it back in. It will go to full field excitation, and provide as much
current as it can at idle.... and engine load.


Whatever you want to believe is fine by me. I hope you don't miss
that hand too much.


--
You can't have a sense of humor, if you have no sense!

On 2009-05-05, Joe Pfeiffer wrote:
"Nutz" writes:

I may be splitting hairs here, doesn't the battery have to have a little bit
of charge in order for the alsternator to be excited enought to generate?

You don't have enough power to turn the engine over (and will refer to
the battery as "dead") a long, long time before the juice is too low to
run the alternator.

The part of the problem I'm wondering about is getting the belt back on,
and tight enough to turn the alternator, with the engine running. Or
else you better live pretty close..

You could also disassemble the alternator and wire the AC from
the gas powered generator to two of the phases of the three phase bridge
in the alternator and use that to charge the battery. The alternator
with no load can produce 120 VAC 3 phase, so the diode bridge should be
rated to handle that much voltage.

Or perhaps the generator may even have a battery start in which
case it will have DC to charge its own battery and that could be wired
to the car's battery as well -- assuming that both are 12V batteries.

Enjoy,
DoN.

--
Email: | Voice (all times): (703) 938-4564
(too) near Washington D.C. | http://www.d-and-d.com/dnichols/DoN.html
--- Black Holes are where God is dividing by zero ---

On Tue, 05 May 2009 18:03:49 -0400, the infamous Wes
scrawled the following:

David Lesher wrote:

You want to charge only long enough to start the engine once. Your drill
will likely be junk, your hand burnt, and your arm sore by then.


Assuming a fair sized drill, 1/2 hp = 373 watts. 13.6v nominal charging = 373/13.6 = 27A
No figuring conversion efficiency at each level.


Yup, that drill is going to be a bit warm and the arm sore. Maybe the olive oil is to
lube the bushings in the cheap walmart drill you are using.

Nah, it's likely for the massage of your arms when you're done with
all this funky ape**** stuff.

Either that or as a, um, lube to amuse yourself while you wait for the
battery to charge. beeg steeky grinne

--
The scientific theory I like best is that the rings of Saturn
are composed entirely of lost airline luggage.
--Mark Russell

"DoN. Nichols" wrote:

On 2009-05-05, Joe Pfeiffer wrote:
"Nutz" writes:

I may be splitting hairs here, doesn't the battery have to have a little bit
of charge in order for the alsternator to be excited enought to generate?

You don't have enough power to turn the engine over (and will refer to
the battery as "dead") a long, long time before the juice is too low to
run the alternator.

The part of the problem I'm wondering about is getting the belt back on,
and tight enough to turn the alternator, with the engine running. Or
else you better live pretty close..

You could also disassemble the alternator and wire the AC from
the gas powered generator to two of the phases of the three phase bridge
in the alternator and use that to charge the battery. The alternator
with no load can produce 120 VAC 3 phase, so the diode bridge should be
rated to handle that much voltage.

Or perhaps the generator may even have a battery start in which
case it will have DC to charge its own battery and that could be wired
to the car's battery as well -- assuming that both are 12V batteries.


I thought the newer alternator diodes were Schottky and have a lower
reverse voltage?


--
You can't have a sense of humor, if you have no sense!

spaco wrote:

[snip]

2. If I was in that situation, I'd consider taking the alternator (or
something else in the vacinity) apart to get a diode. Then I'd slow the
generator down a lot and use it to directly, (now outputing a much lower
voltage, half wave rectified) charge the battery. The duct tape could
be used to keep me from getting zapped. I think.

You don't actually have to take the alternator apart to use its diodes.
Just remove the alternator output terminal and connect the generator AC
output in series with the alternator positive output stud and the wire
leading to the battery. Then, as you suggested, throttle the generator
down to reduce its output voltage.

--
Paul Hovnanian
------------------------------------------------------------------
Why are so many towns named after water towers?

On Tue, 05 May 2009 18:03:49 -0400, Wes wrote:

David Lesher wrote:

You want to charge only long enough to start the engine once. Your drill
will likely be junk, your hand burnt, and your arm sore by then.


Assuming a fair sized drill, 1/2 hp = 373 watts. 13.6v nominal charging = 373/13.6 = 27A
No figuring conversion efficiency at each level.


Yup, that drill is going to be a bit warm and the arm sore. Maybe the olive oil is to
lube the bushings in the cheap walmart drill you are using.

Too many conversion and mechanical losses in spinning the 18V drill
to spin the alternator to turn it back into 12V DC. You will start
out with 2.5 AH in the drill battery and if you're lucky get 1 AH into
the car batery.

Plus, you would have to leave the car ignition key on to excite the
alternator, and all the power you transfer would get sucked up by the
car ECU and other stuff that would be turned on at the same time. Even
the dome light could make the difference betwen Go and No Go.

You would be MUCH better off wiring one 18V drill battery straight to
the car battery, and let the car battery take a surface charge. Then
hook up a second drill battery and try starting the engine with the
two batteries in parallel.

And as to the rotation question - the only difference is the fan,
and the set the brushes take. Corvairs turn their alternators
"backwards" from the usual, so they require a reverse fan or they
don't live long.

-- Bruce --

On Tue, 5 May 2009 19:38:34 -0700 (PDT), Half-Nutz
wrote:

On May 4, 3:46*pm, jeff_wisnia wrote:
I'm thinking that all else left alone, it probably doesn't matter which
way the shaft of an automobile alternator is rotated since the machine
produces ac which is then rectified to create a polarized dc output.

Am I right about that?

The question came up just now when eldest son and I were kibitzing about
this week's "Car Talk" puzzler:

http://www.cartalk.com/content/puzzl...918/index.html

Thanks guys,

Jeff

--
Jeffry Wisnia
(W1BSV + Brass Rat '57 EE)
The speed of light is 1.8*10^12 furlongs per fortnight.

A former poster on this group....
Told a tale of parking his car Many miles into the wilderness, and
leaving on foot for several months.
Upon his return, the battery would be dead, and a few ( 50?) miles
from any passing help.
What he used was an old propane tank, and AIR (80's style smog) pump,
and some lines.

He'd fill the old propane tank with water, throw it on the fire, and
the line ran to the old AIR pump, which was rigged to run backwards
and act as a "turbine" spinning the alternator and charging the battery
to allow his escape in the fall.

That was his story. It was Just crazy enough to work.. Maybe.

Agreed - Just crazy enough that it might work.

But the efficiency would be abysmnal, AFAICT those were carbon-vane
pumps and weren't very efficient going forward, reverse would probably
be worse.

Now an air drill motor, that has far better possibilities...

And as has been brought up, there has to be enough power left in the
battery to excite the field windings on the rotor. Or the alternator
won't start alternating - chancing enough residualk magnetism after
several months of sitting is asking a lot.

If he thought far enough head to disconnect the battery when he left
the car, and the battery was in good shape, it's possible.

If he left in a hurry, he's screwed - "several months" and the
battery will be dead just from the clock and memory drains. Even 5 to
10 milliamps will kill a battery if you let the car sit over two
months - one month is about the limit without a trickle charger or
disconnecting the battery.

-- Bruce --

Bruce L. Bergman writes:

On Tue, 05 May 2009 18:03:49 -0400, Wes wrote:

David Lesher wrote:

You want to charge only long enough to start the engine once. Your drill
will likely be junk, your hand burnt, and your arm sore by then.


Assuming a fair sized drill, 1/2 hp = 373 watts. 13.6v nominal charging = 373/13.6 = 27A
No figuring conversion efficiency at each level.


Yup, that drill is going to be a bit warm and the arm sore. Maybe the olive oil is to
lube the bushings in the cheap walmart drill you are using.

Too many conversion and mechanical losses in spinning the 18V drill
to spin the alternator to turn it back into 12V DC. You will start
out with 2.5 AH in the drill battery and if you're lucky get 1 AH into
the car batery.

It's a 120V drill, and you've got a generator to run it.

Plus, you would have to leave the car ignition key on to excite the
alternator, and all the power you transfer would get sucked up by the
car ECU and other stuff that would be turned on at the same time. Even
the dome light could make the difference betwen Go and No Go.

You would be MUCH better off wiring one 18V drill battery straight to
the car battery, and let the car battery take a surface charge. Then
hook up a second drill battery and try starting the engine with the
two batteries in parallel.

And as to the rotation question - the only difference is the fan,
and the set the brushes take. Corvairs turn their alternators
"backwards" from the usual, so they require a reverse fan or they
don't live long.

-- Bruce --

Bruce L. Bergman writes:

Yup, that drill is going to be a bit warm and the arm sore. Maybe the olive oil is to
lube the bushings in the cheap walmart drill you are using.

Too many conversion and mechanical losses in spinning the 18V drill
to spin the alternator to turn it back into 12V DC. You will start
out with 2.5 AH in the drill battery and if you're lucky get 1 AH into
the car batery.

What "18V" drill?
The problem was stated with a 120VAC drill....

--
A host is a host from coast to
& 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

"Paul Hovnanian P.E." writes:


You don't actually have to take the alternator apart to use its diodes.
Just remove the alternator output terminal and connect the generator AC
output in series with the alternator positive output stud and the wire
leading to the battery. Then, as you suggested, throttle the generator
down to reduce its output voltage.

I think you'll kill the alternator diodes very quickly with this
stunt. What do you think their PIV rating is?

And then WTH will you do?

If you insist; then disconnect the battery from the car, and run a wire
to the positive terminal from the generator. The battery can withstand
short overvoltages far better than anything else in the car. Watch out
for ground loops.

--
A host is a host from coast to
& 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

Bruce L. Bergman wrote:

You would be MUCH better off wiring one 18V drill battery straight to
the car battery, and let the car battery take a surface charge. Then
hook up a second drill battery and try starting the engine with the
two batteries in parallel.


That sounded great but they didn't specify the type of drill.

Wes

"DoN. Nichols" wrote:

You could also disassemble the alternator and wire the AC from
the gas powered generator to two of the phases of the three phase bridge
in the alternator and use that to charge the battery. The alternator
with no load can produce 120 VAC 3 phase, so the diode bridge should be
rated to handle that much voltage.

I think you nailed it. I used to have a converter wired into my 66 plymouth's alternator
that allowed me to run 110v electric tools.

Backwards should work also. I'm assuming a voltage regulator that modulates the field to
control output.

Wes

On Tue, 05 May 2009 07:07:14 -0700, Larry Jaques
wrote:

On Tue, 05 May 2009 09:12:42 -0400, the infamous Joe
scrawled the following:


So he's gonna build a cabin with an electric drill and a socket
wrench?

They forgot to mention his hammah, nailbag, and handsaw.


Must be an erector set scaled up, or maybe a metal pole
building. Not what I visualize when I think "cabin", but these are
modern times.

Look what they refer to as cabins he
http://www.precisioncraft.com/loghom...k/Caribou.html
http://www.precisioncraft.com/loghom...n/Targhee.html
http://imaginactive.typepad.com/phot...log_home_2.jpg
http://www.cedar-log-homes.com/log-home-pictures.htm

Disgusting, isn't it?

Umm, "rustic", "cozy", "quaint", "charming"... Oh hell, you're right -
"disgusting".

Joe

Joe wrote:

On Tue, 05 May 2009 07:07:14 -0700, Larry Jaques
wrote:

On Tue, 05 May 2009 09:12:42 -0400, the infamous Joe
scrawled the following:


So he's gonna build a cabin with an electric drill and a socket
wrench?

They forgot to mention his hammah, nailbag, and handsaw.


Must be an erector set scaled up, or maybe a metal pole
building. Not what I visualize when I think "cabin", but these are
modern times.

Look what they refer to as cabins he
http://www.precisioncraft.com/loghom...k/Caribou.html
http://www.precisioncraft.com/loghom...n/Targhee.html
http://imaginactive.typepad.com/phot...log_home_2.jpg
http://www.cedar-log-homes.com/log-home-pictures.htm

Disgusting, isn't it?

Umm, "rustic", "cozy", "quaint", "charming"... Oh hell, you're right -
"disgusting".

Joe


http://www.loghome.com/hunting_cabin/articles/2536 How do you like
this cabin?


--
You can't have a sense of humor, if you have no sense!

On Wed, 06 May 2009 00:30:06 -0700, Bruce L. Bergman
wrote:

On Tue, 5 May 2009 19:38:34 -0700 (PDT), Half-Nutz
wrote:

On May 4, 3:46Â*pm, jeff_wisnia wrote:
I'm thinking that all else left alone, it probably doesn't matter which
way the shaft of an automobile alternator is rotated since the machine
produces ac which is then rectified to create a polarized dc output.

Am I right about that?

The question came up just now when eldest son and I were kibitzing about
this week's "Car Talk" puzzler:

http://www.cartalk.com/content/puzzl...918/index.html

Thanks guys,

Jeff

--
Jeffry Wisnia
(W1BSV + Brass Rat '57 EE)
The speed of light is 1.8*10^12 furlongs per fortnight.

A former poster on this group....
Told a tale of parking his car Many miles into the wilderness, and
leaving on foot for several months.
Upon his return, the battery would be dead, and a few ( 50?) miles
from any passing help.
What he used was an old propane tank, and AIR (80's style smog) pump,
and some lines.

He'd fill the old propane tank with water, throw it on the fire, and
the line ran to the old AIR pump, which was rigged to run backwards
and act as a "turbine" spinning the alternator and charging the battery
to allow his escape in the fall.

That was his story. It was Just crazy enough to work.. Maybe.

Agreed - Just crazy enough that it might work.

But the efficiency would be abysmnal, AFAICT those were carbon-vane
pumps and weren't very efficient going forward, reverse would probably
be worse.

Now an air drill motor, that has far better possibilities...

And as has been brought up, there has to be enough power left in the
battery to excite the field windings on the rotor. Or the alternator
won't start alternating - chancing enough residualk magnetism after
several months of sitting is asking a lot.

If he thought far enough head to disconnect the battery when he left
the car, and the battery was in good shape, it's possible.

If he left in a hurry, he's screwed - "several months" and the
battery will be dead just from the clock and memory drains. Even 5 to
10 milliamps will kill a battery if you let the car sit over two
months - one month is about the limit without a trickle charger or
disconnecting the battery.

-- Bruce --
Funny, I've left vehicles sit all winter and they start in the
spring. Left them sit all summer and started them in the fall too.
No trickle charger connected.