Metalworking (rec.crafts.metalworking) Discuss various aspects of working with metal, such as machining, welding, metal joining, screwing, casting, hardening/tempering, blacksmithing/forging, spinning and hammer work, sheet metal work.

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Okay, so the switch from 6 volts to 12 volts (automobiles) was made to save
copper and other benefits that I don't remember.

Why, for the same reasons, are we not switching to 24 volts? I understand
that a few military vehicles and commercial trucks are 24 volts. Why not
our automobiles?

Anybody know?

Thanks,
Ivan Vegvary


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Ivan Vegvary wrote:
Okay, so the switch from 6 volts to 12 volts (automobiles) was made to save
copper and other benefits that I don't remember.

Why, for the same reasons, are we not switching to 24 volts? I understand
that a few military vehicles and commercial trucks are 24 volts. Why not
our automobiles?

Anybody know?

Thanks,
Ivan Vegvary

Autos are going to use 34 volts in a couple of years. They are being
designed now.

Bill K7NOM
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Bill Janssen wrote:
Ivan Vegvary wrote:
Okay, so the switch from 6 volts to 12 volts (automobiles) was made to
save copper and other benefits that I don't remember.

Why, for the same reasons, are we not switching to 24 volts? I
understand that a few military vehicles and commercial trucks are 24
volts. Why not our automobiles?

Anybody know?

Thanks,
Ivan Vegvary

Autos are going to use 34 volts in a couple of years. They are being
designed now.

Bill K7NOM

Was supposed to 42 volts several years back - what happened?
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"Ivan Vegvary" wrote in news:97Poj.33$f73.12@trndny08:

Okay, so the switch from 6 volts to 12 volts (automobiles) was made to
save copper and other benefits that I don't remember.

Why, for the same reasons, are we not switching to 24 volts? I
understand that a few military vehicles and commercial trucks are 24
volts. Why not our automobiles?

Anybody know?

Thanks,
Ivan Vegvary



From what I've heard, they're going to skip 24V and go straight to 48V.

This will enable the use of 4 motorcycle-sized batteries that can be
secreted in different areas of the vehicle for fuelled vehicles and 4 car-
sized batteries for electric/hybrid cars.

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On Feb 1, 4:50*pm, "Ivan Vegvary" wrote:
Okay, so the switch from 6 volts to 12 volts (automobiles) was made to save
copper and other benefits that I don't remember.

Why, for the same reasons, are we not switching to 24 volts?


The industry is working up standards for '42V' which will
be a 36V battery with charge voltage circa 42 volts...
just as '12V' has a 12V battery but charges at 14V or more.

Practically this will make the electronics compatible with
telephone type gear (which has 48V battery backup) instead
of the aviation/military gear (which uses 24V battery). Probably
they think it's cheaper this way.


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On Sat, 02 Feb 2008 00:50:13 GMT, with neither quill nor qualm, "Ivan
Vegvary" quickly quoth:

Okay, so the switch from 6 volts to 12 volts (automobiles) was made to save
copper and other benefits that I don't remember.

Why, for the same reasons, are we not switching to 24 volts? I understand
that a few military vehicles and commercial trucks are 24 volts. Why not
our automobiles?

Anybody know?


I vaguely remember an article about that in Popular Science or Pop
Mech years ago, but I don't recall why it didn't catch on. Price of
components, probably.

---
The world is wide, and I will not waste my life in friction
when it could be turned into momentum.
--Frances Willard (1839 - 1898)
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We are in the process of switching to ? 72 ? volts IIRC.
Yes high voltage. Low current. Less copper. Local power supplies
for generating what ever voltage wanted.
There are changes in the industry here and there and now a little more.
I suspect the power for toys will ?maybe? be the same. You just have a
local step-down switcher that can generate high current for boom box toys
and nominal current for lights. Very clean for DVD and GPS and car CPU's.

Martin

Martin H. Eastburn
@ home at Lions' Lair with our computer lionslair at consolidated dot net
TSRA, Endowed; NRA LOH & Patron Member, Golden Eagle, Patriot's Medal.
NRA Second Amendment Task Force Charter Founder
IHMSA and NRA Metallic Silhouette maker & member.
http://lufkinced.com/


Ivan Vegvary wrote:
Okay, so the switch from 6 volts to 12 volts (automobiles) was made to save
copper and other benefits that I don't remember.

Why, for the same reasons, are we not switching to 24 volts? I understand
that a few military vehicles and commercial trucks are 24 volts. Why not
our automobiles?

Anybody know?

Thanks,
Ivan Vegvary


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Maybe that was ? 42 ? - been a couple of years since I sat on a committee
that discussed and designed that long range stuff for automotive.

Martin [ former IEEE and EIA/JEDEC member ]
Martin H. Eastburn
@ home at Lions' Lair with our computer lionslair at consolidated dot net
TSRA, Endowed; NRA LOH & Patron Member, Golden Eagle, Patriot's Medal.
NRA Second Amendment Task Force Charter Founder
IHMSA and NRA Metallic Silhouette maker & member.
http://lufkinced.com/


Martin H. Eastburn wrote:
We are in the process of switching to ? 72 ? volts IIRC.
Yes high voltage. Low current. Less copper. Local power supplies
for generating what ever voltage wanted.
There are changes in the industry here and there and now a little more.
I suspect the power for toys will ?maybe? be the same. You just have a
local step-down switcher that can generate high current for boom box toys
and nominal current for lights. Very clean for DVD and GPS and car CPU's.

Martin

Martin H. Eastburn
@ home at Lions' Lair with our computer lionslair at consolidated dot net
TSRA, Endowed; NRA LOH & Patron Member, Golden Eagle, Patriot's Medal.
NRA Second Amendment Task Force Charter Founder
IHMSA and NRA Metallic Silhouette maker & member.
http://lufkinced.com/


Ivan Vegvary wrote:
Okay, so the switch from 6 volts to 12 volts (automobiles) was made to
save copper and other benefits that I don't remember.

Why, for the same reasons, are we not switching to 24 volts? I
understand that a few military vehicles and commercial trucks are 24
volts. Why not our automobiles?

Anybody know?

Thanks,
Ivan Vegvary

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I too think it's 42 volts that we'll see soon. Remember that it took
from the 1920's to about 1974 or 1980 to get electronics into cars
except for the radio (and Cadillac's photomultiplier headlight dimmer).
I heard that, along with 42 volts comes a combination
starter/alternator built into the auto's flywheel. And electrically
operated valves.
One other big gain for higher voltages is that you loose less power
in the wiring, particularly for the starter.

Pete Stanaitis
----------------

Ivan Vegvary wrote:
Okay, so the switch from 6 volts to 12 volts (automobiles) was made to save
copper and other benefits that I don't remember.

Why, for the same reasons, are we not switching to 24 volts? I understand
that a few military vehicles and commercial trucks are 24 volts. Why not
our automobiles?

Anybody know?

Thanks,
Ivan Vegvary


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"Ivan Vegvary" wrote in message
news:97Poj.33$f73.12@trndny08...
Okay, so the switch from 6 volts to 12 volts (automobiles) was made to
save copper and other benefits that I don't remember.

Why, for the same reasons, are we not switching to 24 volts? I understand
that a few military vehicles and commercial trucks are 24 volts. Why not
our automobiles?

Anybody know?

Thanks,
Ivan Vegvary

I think one of disadvantages of higher voltages is that it could be getting
into the region where it would be a shock hazard under some conditions.
Another is that even 24 volts is getting into the arc welding region where
arcs are more likely to be sustained and more difficult to extinguish.

A relative who is a Ford mechanic indicated that Ford has plans to use a
high power 42-48 volt flywheel alternator and drive all accessories
electrically, thus eliminating the belt drives. As an aside, the early Ford
Model T used a flywheel alternator.

Don Young




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On Fri, 01 Feb 2008 22:16:38 -0800, cavalamb himself
wrote:

spaco wrote:
I too think it's 42 volts that we'll see soon. Remember that it took
from the 1920's to about 1974 or 1980 to get electronics into cars
except for the radio (and Cadillac's photomultiplier headlight dimmer).
I heard that, along with 42 volts comes a combination
starter/alternator built into the auto's flywheel. And electrically
operated valves.
One other big gain for higher voltages is that you loose less power
in the wiring, particularly for the starter.

Pete Stanaitis
----------------


That big gain comes with an interesting drawback...

40+ volts DC is dangerous as all hell!

Richard

Which is why the 42 volt (36 nominal) system is being proposed instead
of a 48volt nominal (54 volt charging) system.Anything over 40 volts
(or is it 42? somewhere real close anyway) is no longer "low voltage"
and ends up regulated much more stringently.
I know 48 volt DC switches tend to have a short lifespan unless
properly designed with arc blowout or VERY fast snap action.
The advent of solid state high-power DC switching is making the 36/42
volt system almost feasible today.

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On Fri, 1 Feb 2008 22:41:02 -0600, "Don Young"
wrote:


"Ivan Vegvary" wrote in message
news:97Poj.33$f73.12@trndny08...
Okay, so the switch from 6 volts to 12 volts (automobiles) was made to
save copper and other benefits that I don't remember.

Why, for the same reasons, are we not switching to 24 volts? I understand
that a few military vehicles and commercial trucks are 24 volts. Why not
our automobiles?

Anybody know?

Thanks,
Ivan Vegvary

I think one of disadvantages of higher voltages is that it could be getting
into the region where it would be a shock hazard under some conditions.
Another is that even 24 volts is getting into the arc welding region where
arcs are more likely to be sustained and more difficult to extinguish.

A relative who is a Ford mechanic indicated that Ford has plans to use a
high power 42-48 volt flywheel alternator and drive all accessories
electrically, thus eliminating the belt drives. As an aside, the early Ford
Model T used a flywheel alternator.

Don Young

And this is when the hood will only open for the manufacturer
certified technician.
Gerry :-)}
London, Canada
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spaco wrote:
I too think it's 42 volts that we'll see soon. Remember that it took
from the 1920's to about 1974 or 1980 to get electronics into cars
except for the radio (and Cadillac's photomultiplier headlight dimmer).
I heard that, along with 42 volts comes a combination
starter/alternator built into the auto's flywheel. And electrically
operated valves.
One other big gain for higher voltages is that you loose less power
in the wiring, particularly for the starter.

Pete Stanaitis
----------------


That big gain comes with an interesting drawback...

40+ volts DC is dangerous as all hell!

Richard
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On Sat, 02 Feb 2008 00:57:05 GMT, Bill Janssen wrote:

Ivan Vegvary wrote:
Okay, so the switch from 6 volts to 12 volts (automobiles) was made to save
copper and other benefits that I don't remember.

Why, for the same reasons, are we not switching to 24 volts? I understand
that a few military vehicles and commercial trucks are 24 volts. Why not
our automobiles?

Anybody know?

Thanks,
Ivan Vegvary

Autos are going to use 34 volts in a couple of years. They are being
designed now.

Bill K7NOM


I read it was going to be 48 volts

Gunner
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there are a several reasons:

1. light bulbs - as you increase the voltage, filaments get thinner. Thin
filaments cannot survive the vibration in a car for very long. Switching to
LEDs which is happening now will eliminate this constraint, but it was in
place for a long time
2. inertia - there's a lot of 12V stuff, costs $$ to change over
3. safety - above 24V, the electrical safety requirements are much more
stringent
4. cost - relative cost of batteries and wire
5. other, such as cold starting versus jump starting, accessories, spare
parts, etc


"Ivan Vegvary" wrote in message
news:97Poj.33$f73.12@trndny08...
Okay, so the switch from 6 volts to 12 volts (automobiles) was made to
save copper and other benefits that I don't remember.

Why, for the same reasons, are we not switching to 24 volts? I understand
that a few military vehicles and commercial trucks are 24 volts. Why not
our automobiles?

Anybody know?

Thanks,
Ivan Vegvary




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clare at snyder.on.ca wrote:
On Fri, 01 Feb 2008 22:16:38 -0800, cavalamb himself
wrote:


spaco wrote:

I too think it's 42 volts that we'll see soon. Remember that it took
from the 1920's to about 1974 or 1980 to get electronics into cars
except for the radio (and Cadillac's photomultiplier headlight dimmer).
I heard that, along with 42 volts comes a combination
starter/alternator built into the auto's flywheel. And electrically
operated valves.
One other big gain for higher voltages is that you loose less power
in the wiring, particularly for the starter.

Pete Stanaitis
----------------


That big gain comes with an interesting drawback...

40+ volts DC is dangerous as all hell!

Richard


Which is why the 42 volt (36 nominal) system is being proposed instead
of a 48volt nominal (54 volt charging) system.Anything over 40 volts
(or is it 42? somewhere real close anyway) is no longer "low voltage"
and ends up regulated much more stringently.
I know 48 volt DC switches tend to have a short lifespan unless
properly designed with arc blowout or VERY fast snap action.
The advent of solid state high-power DC switching is making the 36/42
volt system almost feasible today.



All real good questions, Clare.

Wish I had a valid answer or two...
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If you think THAT is dangerous, how about this?
My neighbor is a volunteer firefighter. He recently told me that (at
least some) of the new hybrids have 300 or 400 volt systems. They have
been trained NOT to go near one of them that has caught fire or even put
water on them for fear of being electrocuted! ----"Even if you hear
then screaming", he says.
So, to me, 42 volts doesn't sound that bad. Hey, what do you think
of having 120 volts and 240 volts running around your house?

Pete Stanaitis
----------------------

cavalamb himself wrote:
spaco wrote:

I too think it's 42 volts that we'll see soon. Remember that it took
from the 1920's to about 1974 or 1980 to get electronics into cars
except for the radio (and Cadillac's photomultiplier headlight dimmer).
I heard that, along with 42 volts comes a combination
starter/alternator built into the auto's flywheel. And electrically
operated valves.
One other big gain for higher voltages is that you loose less power
in the wiring, particularly for the starter.

Pete Stanaitis
----------------


That big gain comes with an interesting drawback...

40+ volts DC is dangerous as all hell!

Richard

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syoung wrote:

Bill Janssen wrote:

Ivan Vegvary wrote:

Okay, so the switch from 6 volts to 12 volts (automobiles) was made
to save copper and other benefits that I don't remember.

Why, for the same reasons, are we not switching to 24 volts? I
understand that a few military vehicles and commercial trucks are 24
volts. Why not our automobiles?

Anybody know?

Thanks,
Ivan Vegvary


Autos are going to use 34 volts in a couple of years. They are being
designed now.

Bill K7NOM


Was supposed to 42 volts several years back - what happened?


POSSIBLY: The NEC limit on "safe" voltage level. ?????
...lew...
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spaco wrote:
I heard that, along with 42 volts comes a combination
starter/alternator built into the auto's flywheel.

Pete Stanaitis


OH MY GOD!!! Not a "Dynastart" like my NSU Sport Ptinz had. :-)
...lew...
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cavalamb himself wrote:
That big gain comes with an interesting drawback...

40+ volts DC is dangerous as all hell!

Richard


Isn't the NEC limit 30 volts?
...lew...


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syoung wrote:
Bill Janssen wrote:
Ivan Vegvary wrote:
Okay, so the switch from 6 volts to 12 volts (automobiles) was made
to save copper and other benefits that I don't remember.

Why, for the same reasons, are we not switching to 24 volts? I
understand that a few military vehicles and commercial trucks are 24
volts. Why not our automobiles?

Anybody know?

Thanks,
Ivan Vegvary

Autos are going to use 34 volts in a couple of years. They are being
designed now.

Bill K7NOM

Was supposed to 42 volts several years back - what happened?

You are correct. I should have said 42 volts. Bill K7NOM
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In article ,
Lew Hartswick wrote:

syoung wrote:

Bill Janssen wrote:

Ivan Vegvary wrote:

Okay, so the switch from 6 volts to 12 volts (automobiles) was made
to save copper and other benefits that I don't remember.

Why, for the same reasons, are we not switching to 24 volts? I
understand that a few military vehicles and commercial trucks are 24
volts. Why not our automobiles?

Anybody know?

Thanks,
Ivan Vegvary

Autos are going to use 34 volts in a couple of years. They are being
designed now.

Bill K7NOM


Was supposed to 42 volts several years back - what happened?


POSSIBLY: The NEC limit on "safe" voltage level. ?????


Has to be at least 48 volts, or telephone wires would have to be handled
as power, not signal, wires. And ring power on telephone lines is 100
volts 20 Hz riding on top of the -48 volts DC.

One can measure the 48 volts across any telephone pair with no off-hook
telephones. When a phone is taken off-hook, the voltage drops to about
6 volts.

Phantom power in microphone circuits is also 48 volts DC.

Joe Gwinn
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On Feb 2, 3:23 pm, spaco wrote:
If you think THAT is dangerous, how about this?
My neighbor is a volunteer firefighter. He recently told me that (at
least some) of the new hybrids have 300 or 400 volt systems. They have
been trained NOT to go near one of them that has caught fire or even put
water on them for fear of being electrocuted! ----"Even if you hear
then screaming", he says.
So, to me, 42 volts doesn't sound that bad. Hey, what do you think
of having 120 volts and 240 volts running around your house?

Pete Stanaitis
----------------------

I am a bit surprised. In general firefighters try to disconnect the
house power, but if they can't, hit the fire with lots of water. The
water will pop the breakers, the firemen are wearing insulating boots,
and if using a hose from a hydrant, are holding a grounded hose. Also
a stream of water from a fire hose is not contiuous and does not
conduct.


Dan
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On Fri, 01 Feb 2008 23:25:38 -0800, Gunner
wrote:

On Sat, 02 Feb 2008 00:57:05 GMT, Bill Janssen wrote:

Ivan Vegvary wrote:
Okay, so the switch from 6 volts to 12 volts (automobiles) was made to save
copper and other benefits that I don't remember.

Why, for the same reasons, are we not switching to 24 volts? I understand
that a few military vehicles and commercial trucks are 24 volts. Why not
our automobiles?

Anybody know?

Thanks,
Ivan Vegvary

Autos are going to use 34 volts in a couple of years. They are being
designed now.

Bill K7NOM


I read it was going to be 48 volts

Gunner

Nope. 48 volts has not been in the running except in electric drive
apps where even 96 and above have been used.. The scuttlebutt for the
last several years has been 36/42

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On Sat, 02 Feb 2008 01:06:20 -0800, cavalamb himself
wrote:

clare at snyder.on.ca wrote:
On Fri, 01 Feb 2008 22:16:38 -0800, cavalamb himself
wrote:


spaco wrote:

I too think it's 42 volts that we'll see soon. Remember that it took
from the 1920's to about 1974 or 1980 to get electronics into cars
except for the radio (and Cadillac's photomultiplier headlight dimmer).
I heard that, along with 42 volts comes a combination
starter/alternator built into the auto's flywheel. And electrically
operated valves.
One other big gain for higher voltages is that you loose less power
in the wiring, particularly for the starter.

Pete Stanaitis
----------------


That big gain comes with an interesting drawback...

40+ volts DC is dangerous as all hell!

Richard


Which is why the 42 volt (36 nominal) system is being proposed instead
of a 48volt nominal (54 volt charging) system.Anything over 40 volts
(or is it 42? somewhere real close anyway) is no longer "low voltage"
and ends up regulated much more stringently.
I know 48 volt DC switches tend to have a short lifespan unless
properly designed with arc blowout or VERY fast snap action.
The advent of solid state high-power DC switching is making the 36/42
volt system almost feasible today.



All real good questions, Clare.

Wish I had a valid answer or two...

I'm likely one of the few on this list who has both been an auto
mechanic and built and driven his own electric car.

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On Feb 2, 3:23 pm, spaco wrote:
If you think THAT is dangerous, how about this?
My neighbor is a volunteer firefighter. He recently told me that (at
least some) of the new hybrids have 300 or 400 volt systems. They have
been trained NOT to go near one of them that has caught fire or even put
water on them for fear of being electrocuted! ----"Even if you hear
then screaming", he says.
So, to me, 42 volts doesn't sound that bad. Hey, what do you think
of having 120 volts and 240 volts running around your house?

Pete Stanaitis


If that 120 and 240 volts was DC instead of AC, I'd be VERY CONCERNED.

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wrote in message
...
On Feb 2, 3:23 pm, spaco wrote:
If you think THAT is dangerous, how about this?
My neighbor is a volunteer firefighter. He recently told me that (at
least some) of the new hybrids have 300 or 400 volt systems. They have
been trained NOT to go near one of them that has caught fire or even put
water on them for fear of being electrocuted! ----"Even if you hear
then screaming", he says.
So, to me, 42 volts doesn't sound that bad. Hey, what do you think
of having 120 volts and 240 volts running around your house?

Pete Stanaitis
----------------------

I am a bit surprised. In general firefighters try to disconnect the
house power, but if they can't, hit the fire with lots of water. The
water will pop the breakers, the firemen are wearing insulating boots,
and if using a hose from a hydrant, are holding a grounded hose. Also
a stream of water from a fire hose is not contiuous and does not
conduct.


Dan


The training I've received on hybrid cars, SUV's and buses offered no such
advice (don't go near). The primary tactical changes in dealing with hybrids
concerned extrication techniques. IE: don't cut the orange wires, don't try
to disconnect the power. As far as fire conditions go we now need to be
concerned with the run off water due to acid/basic electrolyte volume &
fumes. Also some time is spent on battery locations because the weights
involved can affect the center of gravity and how you might stabilize the
vehicle.(some hybrid buses have the batteries on the roof) Concerning
electricity and structure fires we (my dept, others handle it different)
list shutting off the power as a priority but it's not at the top of the
list unless the power is the main problem... like the panel is on fire or
the metal roof/siding is charged... as a rule we shut off the main breaker
prior to overhaul and almost never pull meters, that gets left for the
utility workers. Over the years more firefighters have gotten injured
pulling meters then just fighting fires with the power on. In probie school
our instructor told us fire boots will not protect from shock any better
then a wet pair of sneakers and that electricity will only travel a few feet
up a hose stream. I have been zapped but not often and I could always id the
source.. like burned wires. About 2 months ago my ladder truck became
entangled in the high tension primaries in front of a fire building lucky
for us the ladder stopped on a well insulated section so the arc damage was
minimal, I really would of hated to stand by and watch my NEW hook & ladder
burn. We waited for the utility guys to come and shut off the juice.

Andrew


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"AndrewV" wrote:

our instructor told us fire boots will not protect from shock any better
then a wet pair of sneakers and that electricity will only travel a few feet
up a hose stream. I have been zapped but not often and I could always id the
source.. like burned wires. About 2 months ago my ladder truck became



I don't know about the boots,
but the hose bit is bs

IF you have a continuous stream and a complete path (such as a
connection to a hydrant. It will travel the whole loop.
If you have a discontinuous stream (as in broken up with air)
It won't travel at all [Until you get to medium voltage]

jk
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clare wrote:

I'm likely one of the few on this list who has both been an auto
mechanic and built and driven his own electric car.


I'd be real interested in hearing more about it. I built an electric
car out of a friend's rusted-out VW bug. No way would it pass
inspection, so it was for tinkering, only. I used a jet engine starter
motor/generator, rated at 400 A 28 V continuous. I ran it from an
armature supply of 48 v (4 90 AH trolling motor batteries). I had
a switching regulator on the field supply. It ran suprisingly well, had
LOTS of pep. One problem was the motor was real loud. I was trying to
make a hybrid, and had a motorcycle engine that I'd brought out an
extension from the crankshaft to a stratofortress generator (the
smallest, lightest 400A 28 V electric machine you will EVER see!)
My coupling was junk, and the inline-twin engine had uneven power
strokes, so it was going to snap the shaft real soon.

If I could get another stratofort generator, that might make a really
fine drive scheme. I'd need some reduction gears, though.

Jon

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Default Another Car Battery question


"jk" wrote in message
...
"AndrewV" wrote:

our instructor told us fire boots will not protect from shock any better
then a wet pair of sneakers and that electricity will only travel a few
feet
up a hose stream. I have been zapped but not often and I could always id
the
source.. like burned wires. About 2 months ago my ladder truck became



I don't know about the boots,
but the hose bit is bs

Well it could be, I don't know of any legit testing, but it was 15 yrs ago
and at that point in my career I felt it unwise to argue with the Deputy
Chief. I don't work with hoselines too often since I'm assigned to a truck
company so I haven't given it much thought. I don't know anybody that's
gotten zapped from a electrified hose line so in practice the stream must
not make a good ground. About the boots I've seen rubber fireboots tested
during a utility demo and if your the ground path its time for the dirtnap.

IF you have a continuous stream and a complete path (such as a
connection to a hydrant. It will travel the whole loop.
If you have a discontinuous stream (as in broken up with air)
It won't travel at all [Until you get to medium voltage]

jk


the path would likely be something like this: electrical source---water
stream how solid it is depends on the type of nozzle and how far away it
is---some amount of cotton jacket hose w/metal fittings every 50'-100' wet
and laying on the ground ---fire pump on the engine prob have several other
hoselines off and on the ground---body of the pump---5' rubber jacket feeder
line--- hydrant. so it's not straight forward, if it made a good path I
would think the pump operator would get a tingle from time to time.

I just try to avoid the electrons if possible

Andrew





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spaco wrote:
If you think THAT is dangerous, how about this?
My neighbor is a volunteer firefighter. He recently told me that (at
least some) of the new hybrids have 300 or 400 volt systems. They have
been trained NOT to go near one of them that has caught fire or even put
water on them for fear of being electrocuted! ----"Even if you hear
then screaming", he says.
So, to me, 42 volts doesn't sound that bad. Hey, what do you think
of having 120 volts and 240 volts running around your house?



They have an inertial interrupter that splits the battery system into
two 150 V sets. That works like the inertial fuel cutoff switch that is
on many cars today.

So, is thes for real, that no rescues are to be performed on hybrids?
You just let them burn, then tow the hulk to the junkyard with the
skeletons inside?

Or, is this an insane reaction by some higly misinformed fire chief who
knows nothing about electricity except that it "can hurt you"?

Since I consider myself to actually know something about electricity, I
have REAL doubts anyone could get hurt spraying water on a burning
hybrid car. It is a self-contained electrical system, so how the
current could get back through the water spray is hard to imagine.
Now, I CAN imagine how somebody extricating an accident victim from a
smashed car could get hurt by touching the wrong thing, especially
when using various extrication gear (saws, jaws of life, bolt cutters,
etc.) But, that's part of why the inertial cutoff system is there.

Jon

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Default Another Car Battery question

On Tue, 05 Feb 2008 15:20:05 -0600, Jon Elson wrote:



clare wrote:

I'm likely one of the few on this list who has both been an auto
mechanic and built and driven his own electric car.


I'd be real interested in hearing more about it. I built an electric
car out of a friend's rusted-out VW bug. No way would it pass
inspection, so it was for tinkering, only. I used a jet engine starter
motor/generator, rated at 400 A 28 V continuous. I ran it from an
armature supply of 48 v (4 90 AH trolling motor batteries). I had
a switching regulator on the field supply. It ran suprisingly well, had
LOTS of pep. One problem was the motor was real loud. I was trying to
make a hybrid, and had a motorcycle engine that I'd brought out an
extension from the crankshaft to a stratofortress generator (the
smallest, lightest 400A 28 V electric machine you will EVER see!)
My coupling was junk, and the inline-twin engine had uneven power
strokes, so it was going to snap the shaft real soon.

If I could get another stratofort generator, that might make a really
fine drive scheme. I'd need some reduction gears, though.

Jon

Mine was a 1975 Fiat 128L Sport Coupe with first a 200 amp aircraft
generator, later updated to a 400.
Series aprallel switching (24/48) through a startup resistor of 16ga
stainless steel ribbon, with a rheostat on the field for feild
weakening. A drum switch handled the switching (using 200A contactors)
and an industrial magnetic circuit breaker handled overload protection
(with very good arc suppression). Ran 8 GC2H cart batteries. They were
configured as a 24 volt pack for charging, using a charger from a
Sebring Vanguard.



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