Who Invented Three-Phase?

Half way across town would be a small town

Others invented the transformer. Tesla came up with the concept of the rotating magnetic field in an AC motor, and essentially all the variations of AC motors. And multiphase, or major parts of it.

I wish I knew more about Tesla coils. They are different from ordinary transformers in that the primary, and I think the secondary, are resonant circuits. And I think the length of the secondary is 1/4 wavelength.

Tesla certainly "pioneered" in many areas.

As you decided to snip the c> >

It is, but long distant transmission is not trivial (or wasn't at the time).

Hardy ================================================ Now, what were you saying?

Apparently Edison was trying to promote incandescent lamps and since making a long lasting filament in those days for anything higher than

55 or 110 V forced to use such ridiculously low distribution voltages. Edison was essentially a incandescent lamp salesman, not an electric distribution engineer :-).

However, arc lights work well also in serial circuits, for instance a nominally 6 A circuit across the town. When powered by a 1500 Vdc it could power about 30 arc lamps in series.

snipped-for-privacy@earthl> >> They were using diodes industrially in 1890?!

In wide use in 1890?! (1886?!) Says who?

tor

But the point of this message was regarding the reasons behind the choice to use 3-phase.

Look at the dates involved, 1887-89, see if they support the idea that "ease of rectification" was an important issue for the first Tesla/ Westinghouse distribution grids. It wasn't. The polyphase induction motor and the grid came first. Yes, other benefits became obvious once it was being used.

er:

So you're saying that these were in wide use industrially prior to

1887? And therefore they influenced Westinghouse to fund Tesla's multi-phase AC grid? Evidence?

I never said that, and neither did Michael Terrell.

I agree. I was only following the drift about the secondary advantage of =

low-ripple rectification, and the early types of rectifiers.

No, I am not saying that at all.

Paul=20

Oh, thank you! How "complementary" of you. So you have NPN and PNP = parts,=20 eh?

Mostly you need to learn how to quote and provide proper attribution. A=20 schoolboy can do that. You? Not so much...

Paul

Yes, considering what little was know about electricity at the time. You wonder how they came up with some of those ideas.

Have you ever seen the radio built on a pith helmet, using miniature tubes? There was an article in a early electonics hobby magazine with the plans. One man on rec.antiques.radio+phono built one a few years ago, and posted a photo to the binary group they used.

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It's easy to think outside the box, when you have a cutting torch.

Sigh. Cars use alternators to provide current at lower RPMs and to eliminate brush/commutator failure. Smooth sliprings and brushes last a lot longer. Old cars with a generator had dim headlights at an idle, and you could run the battery down if the vehicle idled too long. The battery was only charged at driving speeds.

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It's easy to think outside the box, when you have a cutting torch.

Oh shit, all those shunt wound brush motors didn't work on AC? Then they couldn't have worked on DC either. DC vs AC does not really change the physics of brush motors.

Just don't try to run a dynamotor on AC. I made that mistake 40 years ago. It ran less than one RPM, and never ran right on DC again. At least it was a useless HV model from an early aircraft RADAR. They were all over the place for a dollar or two at that time.

--
It's easy to think outside the box, when you have a cutting torch.

they

the

Depolarized it. Fixable with what you know now.

In many senses, money, in particular sunk capital, has inertia. Consider the sunk capital value of all the distribution transformers around the country. Or any country. Takes a lot of "push" for a long time to get = it to move.

??=3D))

..

120

means that

proportional to

speed

Not the typical usage. Normal usage is versus speed or load.

?-/

This is also known as "torque ripple" or "speed ripple", and it affects = how=20 smoothly the motor will operate certain sensitive loads, especially at = low=20 RPM, such as power steering. It also contributes to audible noise. Here = is=20 some information:

r-foc-propulsion-pdf.php

Paul=20

The commutator had over 100 segments and two sets of brushes, so it would have been interesting. It's a lot easier with a big electromagnet like they used to 'charge' the magneto on early one cylinder 'Hit or Miss' engines. I had a neighbor who built them and sold them at antique engine shows. His prize possession was a photo of an engine he'd rebuilt, with 'Grandpa Jones' and the check he wrote to buy it.

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It's easy to think outside the box, when you have a cutting torch.

Actually, AC solar panels are the coming thing! You put a micro-inverter on each panel so that you save the costs of one big inverter...

Charlie

. .

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ge

ls.

You've never studied EE I presume? The idea behind ac is that you can easily scale up or down the voltage. High voltage less current equals less losses in transmission. Scaling dc is a different matter. Much harder than a transformer and only recently practical.

Hardy

You've never studied EE I presume? ==================================================== I have a bachelor's degree in Sarcasm. A schoolboy could work it out. You've never studied other usenet fuckwits besides yourself, I presume?

A lot of speculation here much as same by Potter. The historical record was that the problem had to do with Edison's Dynamos. I have no evidence that it had to do with "horseshoe shaped magnets" or not, but that WAS a large problem of the age.

By using a large horseshoe magnet with an armature between the pole ends, one creates a VERY inefficient "magnetic circuit". That of course, creates a very inefficient generator or motor. Just by looking at the motors and generators Tesla built in his lab, a modern engineer (who now understands the parameters of magnetics) can quickly recognize his tight and efficient designs. To ascribe that to just a love of lathe-turned shapes and to thus imply that the designs were an accident rather than due to Tesla's understanding of magnetic circuits is pure and improbable speculation.

Just what is it about Tesla and his inventions that have so many establishment people (and those who quote them) so hot to totally discredit Tesla EVEN TODAY? This is a HUGE arrow pointing to something VERY important apparently hidden there!