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Joined: Dec 2002
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djk Offline
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DC was never really used here in Ireland, except at the very very early stages of electrification late 19th and early 20th century and then really only for lighting. (It was derived from the tram systems) ESB switched over to 10kV & 220/380V 50 Hz distribution very early on.

When did other countries in Europe switch over to 220V/380V 50Hz AC? And were there other systems in use in between? (I know the 127/220V system was, but when was that phased out? How did it work? How was it presented etc?)

We were pretty boring and had 220V + Bonded Neutral since the 1920s.


[This message has been edited by djk (edited 09-17-2003).]

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Vienna: Some districts had 127/220V AC (probably) in 1903, others had 220/440V DC until 1965. As far as I know DC had the same round pin outlets as AC had later. From the 1950ies on (maybe earlier) the remaining areas were converted to 127/220V AC, others to 220/380V. The last 127/220V systems were converted in the late 1970ies. 127/220 meant the customer just got 2 phases of a wye system and no neutral. Large houses got all 3 phases. In Berlin 127/220 still exists but is supposed to be phased out this year. The customer didn't see much of a difference, except for having 2 phases when sticking a phase probe into a receptacle. Naturally polarization was completely useless with 2 equal phase conductors, so there wasn't any color coding.

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Classicsat wrote:

Quote
Well into the 1970s direct line powered radios were sold. Sometime in the 1960s they made them solid state (Have an RCA one somewhere).

Be careful, however. The "hot chassis" solid-state sets are not for plugging into DC supplies!!!

In fact, some of those radios had big labels in the back that said "Caution, Do NOT plug into DC"

Also, while the RADIO section of these transformerless sets could operate on DC, a lot of them came with clocks.

You guessed it. Those clocks could only run on +/- 120 volts AC, 60 cycle. The label on the back or bottom would say 120 volts AC only, 60 cycles (or 60 c/s).

I think General Electric kept making those solid-state hot-chassis sets well into the early 1980s. I have a bunch of radios like that here.

There is a big 3-inch cement-encased dropper resistor in the circuit that gets pretty hot to the touch, although not as hot as the droppers inside the 220-volt AC/DC radios used to get (those used to sometimes burn off the cardboard back covers on the radios!! [Linked Image] ).

I HATE those radios with resistance flexes -- I will never buy one of them. No matter how cute they look.

[This message has been edited by SvenNYC (edited 09-17-2003).]

[This message has been edited by SvenNYC (edited 09-17-2003).]

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djk Offline
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Paul,

Where did the distribution systems get the DC? Local power plants with DC generators? It would seem a little difficult to get it from the 1960s national grid [Linked Image]

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I hope this is not beating a dead horse, but there is an interesting synthesis that was bound to occur somewhere in the world. On 220Y/127V, that seems to be a fairly standard voltage in Central America, but typically at 60Hz. Maybe C-H can confirm or dispute that supposition.

In a catalog listing for Jefferson Electric three-phase ventilated dry-type transformers…
‘General Purpose—Latin American Voltages' 460 V — 220Y/127 V http://www.jeffersonelectric.com/pdf/3-PhaseVent.pdf pg 5

220Y/127V 60Hz in Central American voltage is likely found where 3ø service is brought into larger buildings. This may be the case for some of the Caribbean Islands too. [It’s worth noting that for North America, 127V is also the upper end of permissible voltage for nominal 120V circuits.]

Note that the plain-vanilla North American version of this type of transformer is rated 480 — 208Y/120V {and occasionally 480 — 240/120V 4w ∆.)

[Linked Image from 64.146.180.232]




[This message has been edited by Bjarney (edited 09-17-2003).]

Joined: Apr 2002
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djk — The need for very localized DC generation from rotating machinery would almost have had to have been the case, given voltage drop in relatively low-voltage DC distribution conductors. It seems about ½ mile was the most optimistic extreme for DC circuit lengths without distribution conductors getting ridiculously huge.

The prime advantage of AC transmission and distribution is making use of the AC transformer, to raise [and then lower near the load] voltage, having sent it at a much higher voltage {with much lower losses.}

The one other major advantage of AC is its ready use for brushless induction motors—the ‘current chopping’ needed for DC motors through brushes, commutator and armature generally became no longer necessary with AC.

It is said that early on, Nikola Tesla was hired by Thomas Edison to fix excessive commutator sparking problems in early DC generators and motors.




[This message has been edited by Bjarney (edited 09-17-2003).]

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Quote
Paul, would this domestic dc be 120V to ground or 240V to ground?
At the times I'm talking about, the British 3-wire DC systems were 240 to ground, and thus 480V between outers. (Or thereabouts: As this was before standardization, the specified nominal voltages were between 200/400 and 250/500V depending upon the district.)

Normal residential services were 2-wire 240V, with half the houses tapped from the positive pole and half from the negative. Commercial premises could get a 3-wire 240/480 service.

I understand that there were some 120/240 3-w systems in the very early days (e.g. late 19th/very early 20th century).

Quote
Where did the distribution systems get the DC? Local power plants with DC generators?
Yes, a BJ has mentioned, DC is not easily transposed to higher voltages and the low-ish voltages severely restricts transmission range. Thus DC systems were only practical in urban areas with loads close to the generating station.

Quote
When did other countries in Europe switch over to 220V/380V 50Hz AC? And were there other systems in use in between? (I know the 127/220V system was, but when was that phased out?
I know that parts of France had 127/220V in the past, and this is a question I posed on a French forum some time ago.

A couple of people told me that there was a gradual change from 127/220 to 220/380 after World War II and into the 1950s. But apparenly some areas still had their 127/220 services in the 1960s and even 1970s -- These with actual 127V outlets, not the neutral-less two-phases to give 220V as still exists in some parts of the Continent.

Quote
Of course you could get AC/DC radios well into the late 60s & early 1970s (transformer-less 5-tube "all American 5" sets). Reason was they were cheaper because manufacturer could avoid the cost of a transformer.
In Britain at least, the transformer-less design survived longest in television sets. Live chassis sets with half-wave rectification were still common in the 1970s, which isn't surprising considering that TVs were also one of the last mainstays of vacuum tubes.

By the early 1980s, TV design started moving toward switched-mode (chopper) power supplies. Many of these designs resulted in a chaasis which floated in potential to about half the mains supply level, no matter which way the supply was connected.

So with the earlier sets, one could at least guarantee a zero-volts chassis by observing correct polarization, but on the new sets the chassis would sit at 120V no matter what.

Isolation transformers at the ready! [Linked Image]

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I have worked on both 480V and 600V in industry in Canada.
600V is lower cost in the long run, but it scares the heck out of me. Just kidding.

480V is 277V to ground, 600V is 347V to ground. We electricians get most of our shocks to ground.

347 is the most dangerous voltage to work with. Anything higher, and it 'throws' you out of the circuit, anything lower you still have muscle control to 'pull' away.
I am told 347 just keeps you in the circuit until either you or the grid say 'uncle'. Guess who usually wins.

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You can bet I wouldn't want to argue with 347 volts! [Linked Image]

Looking back at the transformers:
Quote
In a catalog listing for Jefferson Electric three-phase ventilated dry-type transformers…
‘General Purpose—Latin American Voltages' 460 V — 220Y/127 V
I can see that the 220Y/127 arrangement must be the European influence on many Latin American countries, but I wonder how 460V came to be a standard there?

Joined: Aug 2002
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Keep in mind that the voltage seen across your normal two-pin plus ground household or office socket in Colombia, Ecuador, Panama and Venezuela is 120 volts at 60 hertz -- Live to Neutral.

I believe it's a 120v Line-Neutral/240v Line-Line system...in Colombia at least.

There was a small area in Bogota (the capital city) that used to have 150 volts. Supposedly it was the old historic center (Candelaria district). I don't know what happened...they must have converted that neighborhood eventually.

I've never seen 150 volt appliances or lightbulbs for sale there. Everything is marked either 120 or 125 volts.

However a few Colombian-manufactured household wiring devices (some plugs and small 120-volt outlets) meant for 120 volts were rated to 150 volts. Probably because of that legacy 150 volt system. However, the newer versions of these are being re-stamped 125 volts now.

[This message has been edited by SvenNYC (edited 09-24-2003).]

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