Who Invented Three-Phase?

So Edison promised Tesla $20,000 if Tesla would invent AC long distance transmission?

Uh, no.

Apparently Edison set Tesla and another guy to redesigning all the Edison motors and generators. Perhaps made them less costly? Easier to manufacture?

I haven't seen much detail of what Tesla actually did in order to earn that $20,000 from Edison. Maybe Tesla handed Edison a quite valuable invention: industrial motors which look like cylinders. In other words, the design for all modern electric motors.

Maybe that's why Tesla blew a gasket when Edison refused to pay up.

Maybe.

((((((((((((((((((((((( ( ( (o) ) ) ))))))))))))))))))))))) William J. Beaty Research Engineer beaty, chem washington edu UW Chem Dept, Bagley Hall RM74 billb, eskimocom Box 351700, Seattle, WA 98195-1700 ph 206-543-6195

Someone actually built some AC solar panels. You can hook them directly to a transformer. But it's a really silly idea (wish I'd been the one to think of it first!)

Just put solar panels under a gigantic optical chopper: a pair of toothed wheels. Or perhaps use Moire panels with a fine grating. Spin them with a DC motor which runs from the panels. Of course this throws away half the wattage, since the panels are in relative darkness for half of each cycle.

A more genius idea would be to hook them all in series for megavolt DC transmission across several states.

Trivia: the crazed workmate in "Night Shift" who was always manically jabbering his great ideas into a tiny tape recorder? Bill Blazejowski. But me, I don't have a tape recorder. I have a Lightscribe pen with binaural microphones.

((((((((((((((((((((((( ( ( (o) ) ) ))))))))))))))))))))))) William J. Beaty Research Engineer beaty, chem washington edu UW Chem Dept, Bagley Hall RM74 billb, eskimocom Box 351700, Seattle, WA 98195-1700 ph 206-543-6195

The original question was "why was 3phase invented?"

People started giving answers involving ease of rectification. They're all barking up the wrong tree. It doesn't matter if you find articles from 1910 about it.

Yes, 3ph obviously makes for smoother rectified output. But it has nothing to do with why Westinghouse adopted Tesla's invention: the polyphase power grid.

((((((((((((((((((((((( ( ( (o) ) ) ))))))))))))))))))))))) William J. Beaty Research Engineer beaty, chem washington edu UW Chem Dept, Bagley Hall RM74 billb, eskimocom Box 351700, Seattle, WA 98195-1700 ph 206-543-6195

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Hey, there are a bunch of ELECTRICAL EXPERIMENTER mags on wayback:

+1884-1967%2C+ed%22

Here's one:

1917 cover, Doughboy's with Deathrays

How about:

1918 cover, Ray-powered antigravity disk aircraft

((((((((((((((((((((((( ( ( (o) ) ) ))))))))))))))))))))))) William J. Beaty Research Engineer beaty, chem washington edu UW Chem Dept, Bagley Hall RM74 billb, eskimocom Box 351700, Seattle, WA 98195-1700 ph 206-543-6195

It appears to me that Tesla "opinion" of Edison changed, after he picked the brains of Edison and his employees, and managed to get a backer for a company of his own.

He had to get involved in manual labor for a while because his first backers lost money, as did most of his backers.

Picture this.

A guy who is extremely ambitious and egotistical and somewhat nuts, has a "nervous breakdown:

1878 - worked as an assistant engineer for a year. 1879 - Attends college for one year. 1880 - Works for a telegraph company for one year. 1882 - Gets a job with Edison's Paris branch. 1883 - Has another breakdown. 1884 - Emigrates to America and got a job with Edison. Worked a few months until he found a backer.

( Note that Telsla later claimed that Edison promised him over fifty years of salary, for some unspecified accomplishment.) and was probably fired by Edison after a few months.

1885 - As his first venture didn't work out, and he couldn't find a good job or find more backers, he worked as a manual laborer. 1886 - Found backers and formed "Tesla Electric Light & Manufacturing". 1887 - His backers forced him out of the company. 1888 - Got a job with Westinghouse. 1892 - Served as V.P. of the Institute of electrical engineers. ( Observe that Tesla was the kind of guy who used the mystique of the rapidly growing field of electricity, and his short term association with Edison and his organization memberships to hype all kinds of schemes.) 1893 - Used Westinghouse's florescent lamps to entertain at the World's Fair. etc. etc. etc.

It is easy to hype all kinds of future developments that will arise from any new field, such as the Internet, search engines, digital cameras, flash memory, etc. but it is much harder to do as Edison, Ford, Carnegie, and thousands of others did and do, and that is merge new ideas with existing technology and infrastructure, and make the world a better place.

Would you hire a guy like Tesla, or give him money for one of his projects?

If so, let me tell you about some of my ideas.

--
Tom Potter
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http://www.prioritize.biz/
http://voices.yuku.com/forums/66
http://tdp1001.wiki.zoho.com/siteindex.zhtml
http://184.105.237.216/~tompotte/
http://tdp1001.wiki.zoho.com

Cite. This is complete rubbish.

What did his time with Edison have to do with finding a backer.

What did Tesla get from the "brains of Edison and his employees"? Edison is famous for running an invention factory with numerous employees, and exploiting the inventions. Tesla was a one-man lab and was not very effective at exploiting his inventions - like wireless/radio for which Tesla has some base patents.

At least now you don't think "Tesla had a great respect for Edison".

Tesla was a nobody with radical ideas for the time (AC), challenging the existing industry (DC power).

He was a ditch digger when he left Edison.

I don't have the ambition to look at several biographies I have of Tesla. Wikipedia says he went through 3 years of electrical engineering education around 1875. Why is that missing from your list?

Cite. Every source I have read says Tesla quit over the disagreement about pay. He had no "backer". He wound up digging ditches.

Cite. More complete rubbish.

My recollection from the biographies is that Tesla had a second lab. He sold his patents for AC motors to Westinghouse and was a consultant to Westinghouse. A major problem for Tesla was money to fund what he wanted to do. The royalty per-horsepower in the contract with Westinghouse would have made him a rich man. Instead, when Westinghouse got into trouble with his company Tesla waived the royalties for his friend Westinghouse.

Cite. More complete rubbish.

I have never seen a source that said Tesla promoted his association with Edison. Or the AIEE. (I also don't remember Tesla was an officer in the AIEE, but it is irrelevant.)

He didn't have to. He had some spectacular demonstrations for various technical societies - including AC motors (including the "spinning egg"), Tesla coils and fluorescent lighting, and a radio controlled boat. Tesla was, at his peak, a well know man.

The 1893 world fair was one of the major battles in the "war of the currents". Both Edison and Westinghouse competed to supply electricity to the "Columbian Exposition". Westinghouse (and AC) won. The lighting was incandescent - a design created by the Westinghouse Co. to avoid infringing on Edison's patents.

The Exposition was a real big deal in the history of electric power.

The Exposition was a showcase for AC - motors and other. If the Exposition was exactly recreated today I suspect many of us would attend

- for the electrical and other displays. It was spectacular.

I am not aware that fluorescent lamps had anything to do with Westinghouse. They had been demonstrated by Tesla previously - one of the spectacular demonstrations. Tesla repeated some of his other spectacular demonstrations at the Exposition.

Would that be like AC induction motors?

Or AC power generation. The second major battle in the "war of the currents" was whether new generators at Niagra Falls would be AC or DC. AC won. I believe this was the first major AC power generation plant.

Over time the Westinghouse Co. did rather well on a Tesla "project". You basically couldn't make an AC induction motor without infringing on a Tesla patent.

It would help if what you write has something to do with history.

I have doubts much of it will be "sorted out".

If Tesla had kept his funding from royalties on AC motors it would be interesting what would have developed. Much of his work was in an unknown area (wireless) that was not understood. Many of his ideas were impractical and some wrong. He was always eccentric, and was even more so as he got older - part of the "showbiz" (also to get back in the news).

Another problem is Tesla fans who believe wireless power (and some other inventions) were deliberately suppressed. They, in effect, give Tesla a bad name.

In getting an EE degree I never heard Tesla's name. (I heard of Tesla coils in electronics magazines.) One biography speculates that there was a lot of effort back then to avoid Tesla patents on induction motors. It was not in the interest of other corporations to give Tesla any recognition. That may well have influenced technical writing, including an important text from Steinmetz, who was an employee of General Electric the successor to Edison's company.

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That could bring some changes in semiconductor production to provide devices tuned for that application which would be useful in many similar related applications. Like variable frequency drives and class D audio amplifiers.

?-)

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Yes, the Long Legged Mary-Anne ->

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Watch the wrap. Note the picture if you check it out.

Or: Search with:

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Ummm, no.

One big advantage to a micro-inverter is you can make them out of dirt cheap, common, nothing special, parts.

--
Jim Pennino

Remove .spam.sux to reply.

The stator had it's own winding. It wasn't PM.

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

Two major problems with solar panels are extracting the maximum power = under given conditions, and combining the outputs of individual cells so as to obtain as much power as possible when shade or defective cells cause = them to stop generating.

Micro-inverters may be useful if individual cells or small groups of = cells can efficiently boost the voltage high enough to be transmitted = efficiently to the point of use, in whatever form is most suited to its function. An array of solar panels may then become a "smart grid" which adapts to changing conditions and maintains optimum efficiency and reliability.

Generally, AC is best used for voltage conversion, motors, audio, and communications, while DC is best for generation, transmission, storage, = and lighting.

Paul=20

This is the job for the MPPT

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The switcher in the MPPT might be able to drive a DC (series or parallel circuit) directly through a transformer and two diodes, while generating 50/60 Hz AC (which at least resembles a sine waveform :-) will no doubt require an additional switcher.

The problem with DC distribution is that there are no real universal standard voltages, apart for the automotive "12 V" and "24 V" voltages and 48 or 60 V telephone voltages. A much higher standard DC voltage would be required, such as 600 V or even +/-750 V, which still fits within the IEC LV (Low Voltage) directive.

With some standard DC voltage, it would make sense to produce standard devices that feed power into or extract power from such line and hence greatly reduce the cost due to the huge volumes.

When 50/60 Hz sinus AC distribution as the only standard, a great effort is needed to generate AC waveforms (from DC sources) which resembles a sine waveform and on the consuming side, PFCs are needed so that the current waveform resembles the voltage waveform.

Thus, the DC ==> 50/60 Hz sine wave line ==> DC is quite complex. However, the DC ==> x kHz square wave ==> DC line on the producing side and DC line ==> y kHz ==> DC load on the consuming side is simpler and more efficient. If only we could agree on a standard DC line voltage :-).

Actually, VF motor drives have DC "links" that are the full wave = rectified=20 voltage of standard 240 VAC and 480 VAC three phase power universally = used=20 for industrial motors up to several hundred HP. So 360 and 720 VDC are=20 logical choices. Moreover, railroads use 720 VDC. So the means to = produce=20 standard AC power already exists.

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The PWM motor controllers already perform this complex conversion quite=20 efficiently and it is a mature technology. The high frequency components = of=20 the PWM are in the kilohertz range and can be made higher as components=20 become available at higher switching speeds, voltages, and efficiencies. =

Square waves and modified sine wave approximations such as are produced = by=20 many 12V inverters are noisy and the high frequency components are = difficult=20 for transmission over any distance.

There may be some problems at higher voltages as used for residential=20 distribution (mostly 14.4 kV). But it would not be difficult to replace = the=20 usual residential 240 VAC split phase service with 360 VDC, and at the = meter=20 it could be converted to the usual 120/240 VAC service or 120/208 VAC = three=20 phase, and many appliances can already operate just fine on the raw DC = if=20 they use a switching supply which uses rectifiers and big capacitors to = make=20 DC and then use efficient high frequency conversion to the voltages = needed.

Paul=20

I have seen such DC links in paper machines with lots of VFD controlled motors.

At least in Europe the standard 230/400 V wye/delta would with a six pulse rectifier would produce something like 480 Vdc, which is not ground referenced. Rectifying from 690 V delta (common with larger industrial motors in Europe) would produce something like 680 Vdc, again without ground reference.

Unfortunately these cause a huge amount of RFI. Shielded power cables are often needed, if the VFD is not co-located with the VFD. An integrated VFD+motor combo would be OK.

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Just the same, many but not all DC generators and many perhaps most dynamotors used stator magnetic materials that are/were retentive. I repolarized enough generators and a few dynamotors in my youth. The residual magnetism was important to their startup an operation, and = normal operating currents were not enough to repolarize.

?-)

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I tried to repolarize it, but it didn't help. I'm familiar with the process, since there were still a lot of late '50s cars around in the mid '60s. That was the only time I was unable to get a DC motor to run gain, but it had sat in storage for over 20 years so it may have been defective when I got it. I kept a pair of fully charged car batteries under my workbench, so I had the required 24 volts for that dynamotor. It was removed from one of two early W.W.II aircraft RADAR systems from the school's physics department.

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

You're aware that most/many of WWII aircraft systems were 400 cps and the output of radar system M/G set were typically 1000 cps?