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PICList Thread
'[OT] off topic AC Power'
1998\01\29@201942 by Wayne Foletta

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Ed:

You are right - the first power generators were DC. One of the reasons
for Edison switching to AC, as I remember reading, was a marketing ploy!
It seems there were some early fatal accidents with high voltage DC
power and with lower voltage AC, it was suppose to be totally safe.
Edison did some public demonstrations that showed the safety of AC with
a goat or some other animal. Don't recall the reason for 60Hz choice.
I'll find that history book tonight and let you know.

- Wayne Foletta
BMI - Saratoga, CA
The Power of Quality

{Quote hidden}

1998\01\29@220653 by Eric Smith

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Wayne Foletta <waynespamKILLspamELECTROTEK.COM> wrote:
> You are right - the first power generators were DC. One of the reasons
> for Edison switching to AC, as I remember reading, was a marketing ploy!
> It seems there were some early fatal accidents with high voltage DC
> power and with lower voltage AC, it was suppose to be totally safe.
> Edison did some public demonstrations that showed the safety of AC with
> a goat or some other animal. Don't recall the reason for 60Hz choice.
> I'll find that history book tonight and let you know.

I think you've got that backwards.  Edison vehemently opposed the use of AC,
and gave repeated public demonstrations of the dangers of AC by electrocuting
animals with it.  I somehow doubt that safety was his real motivation; it
sounds more like NIH Syndrome.

Cheers,
Eric

1998\01\29@223759 by John Payson

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> Wayne Foletta <.....wayneKILLspamspam.....ELECTROTEK.COM> wrote:
> > You are right - the first power generators were DC. One of the reasons
> > for Edison switching to AC, as I remember reading, was a marketing ploy!
> > It seems there were some early fatal accidents with high voltage DC
> > power and with lower voltage AC, it was suppose to be totally safe.
> > Edison did some public demonstrations that showed the safety of AC with
> > a goat or some other animal. Don't recall the reason for 60Hz choice.
> > I'll find that history book tonight and let you know.
>
> I think you've got that backwards.  Edison vehemently opposed the use of AC,
> and gave repeated public demonstrations of the dangers of AC by electrocuting
> animals with it.  I somehow doubt that safety was his real motivation; it
> sounds more like NIH Syndrome.

According to Smithsonian Magazine's article on Coney Island awhile ago, one
such "demonstration" was performed on an elephant that had killed someone
and needed to be put down.  Poison had proven ineffective, and other methods
were rules too hazardous or unacceptable; in this instance, electrocution may
in fact have been the best method to kill the animal.

On the other hand, I have also heard [unconfirmed] that the electric chair
was also invented for the purpose of showing how hazardous AC was; I have
no idea whether that legend is true or not.

1998\01\29@224012 by Rob Zitka

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At 03:03 AM 1/30/98 -0000, you wrote:
>Wayne Foletta <EraseMEwaynespam_OUTspamTakeThisOuTELECTROTEK.COM> wrote:
>> You are right - the first power generators were DC. One of the reasons
>> for Edison switching to AC, as I remember reading, was a marketing ploy!
>> It seems there were some early fatal accidents with high voltage DC
>> power and with lower voltage AC, it was suppose to be totally safe.
>> Edison did some public demonstrations that showed the safety of AC with
>> a goat or some other animal. Don't recall the reason for 60Hz choice.
>> I'll find that history book tonight and let you know.
>
>I think you've got that backwards.  Edison vehemently opposed the use of AC,
>and gave repeated public demonstrations of the dangers of AC by electrocuting
>animals with it.  I somehow doubt that safety was his real motivation; it
>sounds more like NIH Syndrome.

As I recall seeing one time, Edison was on the side of DC and Tesla a
supporter of AC.  I believe when a electric chair electrocution using DC
went wrong, people quickly embraced AC, to Edison's dismay.

Rob

1998\01\30@130856 by Wayne Foletta

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Eric:
Yep. I guess my memory is AC  - I reversed history!
Rereading the accounts of the day:
"Edison's strategy was to convince everyone that Westinghouse's AC
current was unsafe. He hired scientists to travel around and give public
demonstrations of this by electrocuting cats, dogs, and horses with AC
current. His ultimate victory came with New York State's switch from
hanging to the electric chair, which was, of course, powered by a
Westinghouse AC generator." - The Electric Chair.

I forgot that it was Tesla who invented AC concepts while working for
Edison who was holding onto DC devices to protect his product sales. It
was Tesla who left Edison and went to Westinghouse with his AC ideas and
patents on alternating-current motors, dynamos and transformers. ( I
guess they didn't have employee contracts with intellectual property
rights clauses back then.)

- Wayne Foletta
BMI - Saratoga, CA

{Quote hidden}

1998\01\30@190900 by M Walter

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At 08:17 PM 01/29/98 -0500, you wrote:
>Ed:
>
>You are right - the first power generators were DC. One of the reasons
>for Edison switching to AC, as I remember reading, was a marketing ploy!
>It seems there were some early fatal accidents with high voltage DC
>power and with lower voltage AC, it was suppose to be totally safe.
>Edison did some public demonstrations that showed the safety of AC with
>a goat or some other animal. Don't recall the reason for 60Hz choice.
>I'll find that history book tonight and let you know.
>
>- Wayne Foletta
>BMI - Saratoga, CA
>The Power of Quality
>
>> ----------
>> From:         Ed Koffeman[SMTP:RemoveMEedkTakeThisOuTspamCYBERRAMP.NET]
>> Reply To:     pic microcontroller discussion list
>> Sent:         Thursday, January 29, 1998 2:17 PM
>> To:   spamBeGonePICLISTspamBeGonespamMITVMA.MIT.EDU
>> Subject:      Re: off topic
I believe that in regards to the DC vs AC arguement that you have Mr.
Edison on the wrong side. It was Westinghouse with Tesla who was the
proponent of AC power. I believe that there was also a fight as to whether
or not the first electric chair would be AC or DC powered: neither side
wanted THAT honor.
Mark Walter

1998\01\31@090821 by Tom Mariner

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> I believe that in regards to the DC vs AC arguement that you have Mr.
> Edison on the wrong side. It was Westinghouse with Tesla who was the
> proponent of AC power. I believe that there was also a fight as to
whether
> or not the first electric chair would be AC or DC powered: neither side
> wanted THAT honor.
> Mark Walter

Correct -- The story goes that Thomas Alva never relented in his support
for DC -- and created the Electric Chair to demonstrate the danger of AC.

Tom

1998\01\31@234942 by Tom Gretton

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From my recollection my 4th year power systems engineering course,  the
reasoning for the choice of 60Hz was to minimize the losses incurred in the
transformer cores (ie: magnetic heating of the iron, etc.)  Apparently
somebody did some math (and a lot of laboratory testing to demonstrate that
the losses in transformation are at a minimum at approximately 57 Hz.

This odd number got rounded up to 60 Hz by in North America.  The Europeans,
however, elected to go for the lower number because it reduced the speed of
the generators required to produce the desired frequency.

Ontario Hydro did remotor everyone's houses in a massive switch from 25Hz to
60 Hz many years ago.  However, there is still (at least as of 15 years ago)
an industrial 25Hz network in operation in parts of Ontario because the cost
to convert for some industries was too great.

400 Hz was chosen as the frequency of choice for computer applications
because the higher frequencies are easier to filter to pure DC.


Tom


-----Original Message-----
From: Wayne Foletta <TakeThisOuTwayneEraseMEspamspam_OUTELECTROTEK.COM>
To: RemoveMEPICLISTspamTakeThisOuTMITVMA.MIT.EDU <PICLISTEraseMEspam.....MITVMA.MIT.EDU>
Date: Thursday 29 January 1998 20:22
Subject: Re: [OT] off topic AC Power


|Ed:
|
|.... Don't recall the reason for 60Hz choice.
|I'll find that history book tonight and let you know.
|
|- Wayne Foletta
|BMI - Saratoga, CA
|The Power of Quality
|


'[OT] off topic AC Power'
1998\02\01@050234 by Eric Smith
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Tom Gretton <EraseMEtgrettonspamINFORAMP.NET> wrote:
> 400 Hz was chosen as the frequency of choice for computer applications
> because the higher frequencies are easier to filter to pure DC.

I'm not familiar with 400 Hz for computer applications, but for aviation
applications I'm told that it was chosen because it allows for the use of
lower-mass transformers.

Eric

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