The Current War

[bad Chad]

New movie coming out about the Ac/dc war over which current would win the day, think beta vs vhs.

[rocker59]

New movie coming out about the Ac/dc war over which current would win the day, think beta vs vhs.

AC won for home and commercial a century ago.

It took a long tme, but AC is taking over the  railroad locomotive industry.

My money is on AC for automotive propulsion. 

[SmithSwede]

I don't think Edison was personally involved, but I've long been disgusted at the electrocution of Topsy the elephant in 1903.  There is actually an Edison film of the elephant's execution.

[Chuck in Indiana]

It was a different time.. but agreed.

[n3303j]

I thought AC won the war too. Then one day I got bored and started reading about high tension power transmission systems. It seems a fair amount of power is radiated and lost off an AC line. Less is lost off a DC line. Now that converting AC to DC and then back again in large power applications is a simple, solid state process a fair amount of power is transmitted on very long distance lines as Direct Current to coserve the energy that would be lost if transmitted as AC.
https://en.m.wikipedia.org/wiki/High-voltage_direct_current

[kirkemon]

In the late 19th century Nikola Tesla defeated Thomas Edison in the AC/DC battle of electric current.
https://tinyurl.com/y6yk2rol

[Loop Tonti EV]

Shocking.

[Huzo]

I don't think Edison was personally involved, but I've long been disgusted at the electrocution of Topsy the elephant in 1903.  There is actually an Edison film of the elephant's execution.

Seen it.
Horrible.

[rocker59]

I thought AC won the war too. Then one day I got bored and started reading about high tension power transmission systems. It seems a fair amount of power is radiated and lost off an AC line. Less is lost off a DC line. Now that converting AC to DC and then back again in large power applications is a simple, solid state process a fair amount of power is transmitted on very long distance lines as Direct Current to coserve the energy that would be lost if transmitted as AC.
https://en.m.wikipedia.org/wiki/High-voltage_direct_current

I don't know about that.  One of the reasons AC won out over a century ago was because AC transmitted further, easier, with lower losses.  Fewer substations were required with AC.

[cloudbase]

[Chuck in Indiana]

Tesla was talking about transmitting electricity long distances wirelessly. 

[kirb]

AC is easier to boost voltage through a transformer because of the alternating sine wave. DC cannot. Substations are easy to reduce voltage and distribute over 3 phase power lines.
AC generators are MUCH less maintenance- no commutator brushes that need service. There are no electrical connections between the rotor and the outside world (on large machines).
DC never crosses zero like AC does twice a cycle- more difficult to interrupt current. Very altitude dependent.
AC cannot be stored easily like DC can.

The AC/DC wars were being sold at a different time- Edison (General Electric) was trying to sell complete power systems running DC to a small area. They never considered an interconnected country. The systems were complete- power house, distribution, etc. That was before house electricity was more than a few light bulbs and a fan. The systems were difficult to expand and hard to transmit long distance.

Westinghouse took the AC side which was more of large central power plants, transmission lines, and distribution. Spoiler alert- AC won out. Eventually 60Hz and three phase became the standard.

I still work on a hydroelectric plant that ran all the power for Portland, MI. The generators are wired two-phase and converted to three phase through a unique transformer connection developed by Westinghouse. Most all the 25hz hydros are gone...I still run across 25Hz transformers that used to be run off a hydro plant that doesn't exist anymore...you can run them on 60Hz (but they are HUGE).

I still come across old stuff now and again, but usually only in privately owned hydro plants. The best is the 2" thick marble control panels built by GE. Later were 2" thick slate, last generation was 2" thick asbestos. Most of that equipment is long gone due to it being not safe.

[n3303j]

I don't know about that.  One of the reasons AC won out over a century ago was because AC transmitted further, easier, with lower losses.  Fewer substations were required with AC.

Did you read the Wiki article?
It supports my statement.

AC transmitted better in the old days because they could run it through transformers.
DC was generated, transmitted and delivered at home line voltage.
Now that DC can be transformed it transmits more economically than AC.
Just need lines long enough to amortize the hardware.

[tommy2cyl]

Angus Young is the only human alive to be able to combine both AC & DC in tandem and utilize the advantages of both.

[n3303j]

Whenever power has to be transmitted over long distances, DC transmission is the most economical solution compared to high-voltage AC. Two remote AC systems, with a distance of typically 300 to 3000 km (and more), are coupled together via an HVDC transmission line such as an overhead line or a DC cable.
https://www.energy.siemens.com
Long-distance power transmission - Siemens

[rschrum]

They killed Topsy? The bastards.

[Blaufeld66]

All hail Tesla!

https://theoatmeal.com/comics/tesla

[Chuck in Indiana]

All hail Tesla!

https://theoatmeal.com/comics/tesla

  Tesla was Ed the Rocket Scientist's hero..

[Zoom Zoom]

Having seen a couple documentaries on this subject over the years, this could be an interesting movie about the birth of electrification for everyone. I would imagine they will need to hold close to facts since much is well documented, but this was a dramatic thing at the time. Each trying to sell their idea to investors and the public. I'm looking forward to seeing it.

John Henry

[Moto]

I've been reading a biography of Tesla (Tesla: Man Out of Time, by Margaret Cheney, 1981) and plan to see Current War this weekend. 

I've also gotten really excited lately about the Telechron clock and can't wait for the release of that new movie! Seriously, Henry E. Warren invented the synchronized power system we enjoy today specifically to synchonize his company's Telechron home clocks to Naval Observatory time, by counting regulated cycles in the power mains. He sold the power companies special mechanical/electric clocks to monitor their cumulative cycles per day or week. As a result, power grids could easily be formed once all the power generators were in synch.

Now there are three massive grids in North America, each consisting of many large generators that are electrically synched in such a way that they are in effect a single giant mass, equal to the combined masses of their many rotors! ! There is a real-time map allowing us all to monitor the efforts to keep the grids on time, showing each one running a little bit fast or slow, as loads are applied or removed to regulate cycles per second: fnetpublic.utk.edu/frequencymap.html! (This can provide hours of free entertainment.)

It doesn't get any better than this! Whether Hollywood is ready for a series of electrical pioneer movies remains unknown.

Moto

 

[normzone]

   Shocking.   

Revolting ...

[keuka4884]

And speaking of movies to watch in the coming weeks - I'm looking forward to watching Midway and Ford vs Ferrari. Ford vs Ferrari in Imax!!

[Moto]

I just saw The Current War, and don't recommend it. It was devoid of drama and excitement. Some details of the battle over AC/DC were present and correct, but they seemed to me to be mentioned just to add a little cred to a boring plot.

Maybe its harder to make an exciting movie about electrical current standards than you'd think.

I was hoping for some of the really vivid scenes I've been reading about in Tesla's biography, but no such luck. I suppose some will have other opinions, but I'd advise reading some reviews before going.

Moto

[organfixsing]

One problem with DC is that if there is an arc established, the arc will not quit until it runs out of ionized gas and so can continue to arc until a lot of stuff  is destroyed.
There is a story of early DC reticulation in Sydney CBD which when a light bulb broke the filament, the light bulb would arc over internally then continue up the lead to the ceiling and then further, creating a very definite fire hazard.
At least with AC, the voltage (EMF) goes to zero regularly and so can most likely extinguish the arc.

Cheers

Brian

[grebmrof]

An interesting bit of historical fiction on all of this:  "The Last Days of Night" by Graham Moore  Good book, I read it a couple of years back.

[larrys]

One problem with DC is that if there is an arc established, the arc will not quit until it runs out of ionized gas and so can continue to arc until a lot of stuff  is destroyed.
Brian

That is proving to be an issue with photo-voltaic systems. The panels make DC power. DC disconnects must be constructed very differently from AC disconnects.
Larry

[Zoom Zoom]

I just saw The Current War, and don't recommend it. It was devoid of drama and excitement. Some details of the battle over AC/DC were present and correct, but they seemed to me to be mentioned just to add a little cred to a boring plot.

Maybe its harder to make an exciting movie about electrical current standards than you'd think.

I was hoping for some of the really vivid scenes I've been reading about in Tesla's biography, but no such luck. I suppose some will have other opinions, but I'd advise reading some reviews before going.

Moto

That's disappointing.

John Henry

[PeteS]

One problem with DC is that if there is an arc established, the arc will not quit until it runs out of ionized gas and so can continue to arc until a lot of stuff  is destroyed.
There is a story of early DC reticulation in Sydney CBD which when a light bulb broke the filament, the light bulb would arc over internally then continue up the lead to the ceiling and then further, creating a very definite fire hazard.
At least with AC, the voltage (EMF) goes to zero regularly and so can most likely extinguish the arc.

Cheers

Brian

The first ship I was on in the Navy was the USS Calvert APA32. It was primarily DC powered with a small AC generator so the Captain could use his electric shaver.
As an Electricians Mate I served watches on the main switchboard pictured below. As you can see it was open with breakers and knife switches. Main power was 400V DC.
The points on the breakers had coils next to them. When a breaker was open, the inductive surge through the coil would create a magnetic field that would quench the arc.
The point about having to clean the commutator is true. A dirty job that was done in 135F temperatures of the engine room.

Not me in the photo but taken on a previous cruise.



upload image


Pete