just got electrocuted, curious why it didn't seriously hurt

[Paul Marossy]

one week back in school i was having a really bad gremlin problem with my gear, mind you it was all old second hand stuff but still. my cab when kaput and while it was in the shop my head went kaput. so while i was saving up for a new head my sound guy lent me a Frankensteined  bass rig of sorts. a dod crossover for a pre, a 1977 Yamaha stereo 300 as and amp and a 1x18 peavey  sub. it was afoul. well the amp was only working on the left side and the ride side was going bad  at lest that what he said. well i was setting up one night plugged into the wrong side and zap. when i came to  i was speaking jibe-rage and i  pissed all over my self. isn't electricity cool.

Wow. Sounds like it shocked the crap out of you! So to speak.

[PRR]

> outlet is ...125V.  ...coming out of the transformer might be 135VAC

You surely have 127.5 at the pole (2% max feeder drop) (except at my house).

You pay on the 125V-126V at the meter, not whatever is on the pole or some nominal "normal" voltage. The meter measures the voltage too. Anything else would beg for gross company trickery.

> reduce the amount of current needed for the power grid so it doesn't have to work as hard.

Yes, this is part of the subtle trickery of the electric racket. It has become as costly (really) to deliver residential power as it costs to make power at the dam or boiler. And residential loads always increase (despite "green" thinking). And the cost of expanding existing lines rises as land-values rise. And money must be sunk for long-term returns which (for various reasons) may not happen ("stranded costs"). It is difficult to be an honest utility company. It is more difficult to be a successful utility company, and they work the system for every advantage.

> 50Hz because it's not as dangerous to humans

Insignificantly. DC hurts different from AC; is not "more safe". Above ~~100KHz energy tends to flow over the skin, less inside (but it is very possible to be burned by RF energy). The difference 50 versus 60 is not about safety.

> 40 V isn't really high enough to spark much of a distance/ arc over a long distance.

110V even 240V won't jump through air without a trick; with tricks arc-welding is normally working near 40V.

No, for "average" humans 25V through skin is pretty safe and 40V through skin is hardly-ever dangerous. All things considered, 40V power around saws and ladders is a reasonable risk. The drawback is you need special 40V motors (same rotors with 1/3rd turns of 3X size wire) and you need very fat copper in extension cords to deliver significant power. (Cars do OK with 12V even 6V power, but "cords" are very fat and only a few feet long.)

> I've wondered why there was 50Hz in some places in the world and 60Hz in others. I guess it's because of how things started in those areas. Too late to globally standardize I suppose?

With incandescent lamps flicker is a problem. 10Hz flickers very bad. 400Hz flicker is quite invisible. Flicker is influenced both by eye-response and by filament thermal time constant.

The decision 60Hz or 60Hz may be related to early carbon-thread lamps and later tungsten lamps.


The first BIG Alternating-Current rig was Niagara Falls.

Actually the main point was POWER. The Falls had lots of power, cheap. How it was delivered was not too critical.

All methods were considered. Belts, ropes, cables, shafts, compressed air, DC, even AC. Yes, they proposed compressing air with water mills and piping it 20 miles to Buffalo to turn mills there. Yes, cable-drive can be quite effective over several miles, moreso than DC at practical voltages. DC was used for arc-lights in the village at the top of the falls, but only 2,000 horsepower worth.

The old part of Niagara's AC systems (worked good for 111 years) is 25 Cycles per Second. (We didn't Hertz yet.)

Why?

1) Niagara's loads were BIG motors. To work them at 60Hz, they'd either spin so fast they would burst, or need so many poles (separate windings) that cost would rise.

2) "Electrical Iron" was not invented yet. Iron in a transformer has losses proportional to frequency. Losses at 25Hz are much lower. OTOH a 25Hz transformer is larger than a 60Hz transformer. With lossy iron, size is a toss-up because you need size to throw heat. Silicon iron has much lower losses, and modern transformer-iron losses are quite low.... but not then.

3) Commutator AC motors were still common (Tesla's ideas were young), and they favor low frequency.

4) Pittsburgh Reduction (now Alcoa) needed HUGE amounts of DC; Buffalo had lots of DC lighting infrastructure. Rotary converters would drop AC to DC near point of use, but they don't like high Hz.

5) Niagara was mainly about turning machinery. Lighting is a different problem: flicker. Westinghouse had used 60Hz(!) for AC lighting. 60Hz for lights and 30Hz for big machinery would be simple. However the water turbines were already built and turned 250 RPM. 30 CPS, 1,800 Cycles per Minute, does not fit 250RPM.

16.67Hz and 41.67 were debated. 25Hz seems to have been a simple compromise.

That covers Powerhouses 1 and 2. Generators were built 2-phase but by that time the advantage of 3-phase was clear, and the 11,000V line to Buffalo was built 3-phase "Scott" connected to 2-phase.

Later Schoellkopf built a third station making DC for local industry, 125Hz single-phase, and 30Hz 3-phase, but shifted to mostly DC with a little 25Hz AC.

The older plants were phased-out because the Schoellkopf complex had a higher water-drop.

Canada built their Rankine station on similar electrical lines (but cleverer hydraulics).

Some large 60Hz power was introduced in 1946.

In 1956 the Schoellkopf complex was crushed by a rockslide. It was rebuilt 60Hz.

2006 the last 25Hz machine tripped-out and was never put back in service.

[Paul Marossy]

Interesting stuff PRR. I wonder if one day there will be too many people for the power grid and they will "run out" of power. They sure could use a whole lot more solar power here in the USA. Too bad it's cost prohibitive for 95% of the people that would like to use it.

[wavley]

Interesting stuff PRR. I wonder if one day there will be too many people for the power grid and they will "run out" of power. They sure could use a whole lot more solar power here in the USA. Too bad it's cost prohibitive for 95% of the people that would like to use it.

It's getting cheaper, I just watched a thing about a guy that developed a solar panel on a flexible substrate that he thinks once it goes into mass production it will cost about a buck per watt.  It can also take light from any angle, he demonstrated by bending them across a terra cotta roof.

One of my co-workers is currently making a rig to solar charge his electric lawn mower and the solar/charging stuff was much less than the mower.  Of course he lives in town so it works for him, you couldn't pay me to try an cut my country couple of acres with anything less than rider, I tried with a push mower for one summer... yikes.

[Paul Marossy]

It depends on where you live, too. Here in Las Vegas where it can be 115 deg F or more in the summer, electrical demand is HUGE because every AC unit in town is on and basically never stops running for what I call the six months of summer. So you can't in reality run your house on 100% solar power unless you had quite a large area to put a bazillion solar panels, which would be out of reach for 95% of people because of the cost and the thousands of HOAs here would never allow it anyway. And that would supply maybe 50% of the power needed for the average user. However, it helps somewhat. If everyone had some, it would inject a sizable amount of energy into the grid. I understand this is what is actually done in Germany, which seems very smart to me. They are even along side the autobahn.

Here's what $1.3 million in solar panels looks like (I took these pictures myself about two weeks ago):









In each picture is about 25-30% of the panels on the approx. 40,000 sq ft roof. These still won't quite power the main room in the building which has (9) 25-ton units operating on 460V 3 phase, or the many other units on the building. But they will help offset the peak load somewhat. The only way this building owner did this is because they got a grant from the government for the work. Otherwise, it would still just be a pipe dream for them to be "more green".

Now if you had a cabin up in the hills, no AC and very minimal electrical load, then yeah maybe solar can actually almost power all your stuff. Except for maybe the refrigerator.

[wavley]

I wasn't disagreeing with you at all.  I've looked into supplementing my electricity habits with solar and personal wind turbines and it's just not feasible for me right now.  I was just pointing out that technology is starting to make some great advances in making these things cheaper and maybe in the somewhat near future these things will be more of an option.  My co-worker's lawnmower experiment is merely because he is a scientist (electro-chemist is is current position) and is curious to see if he can make it work, but it's of absolutely no use for a guy like me.  I mean maybe it could power my pedal board, but not big ole tube amps and I'm certainly not going to cut my grass that way.  Not to start a bigger or political debate, but I've noticed over the years in my current career that certain big lumbering entities latch on to outdated and more expensive technologies for this kind of stuff because they are produced by big companies with political clout while there is superior technology being produced by smaller, nimble, and innovative companies with little or no clout.  That and it's easier to explain older/less complicated solutions to the morons that tend to run things. 

[Paul Marossy]

I know wavely, I was just pointing out something from my perspective and had some info to share. I wish solar power was a more economical & practical thing that most people could do instead of it being out of reach for 95% of people.

As you point out, the large companies "with clout" try to stamp out the small innovative ones that have something better to offer. One of the many things I hate about "corporate America".

[PRR]

> I wonder if one day there will be too many people for the power grid

We are frighteningly close to that all the time. Figure the size of an extension cord to run your whole house (#2 wire) and long enough to reach the dam or coal-burner. It's tens of thousands of dollars. Yes, there's mild economy in sharing (not everybody peaks at once) and significant economy in voltage transformation (if load is large enough to justify purchase).

Utilities generally delay up-grading the wires until things get dire. The feeder to the island near me was patched and patched for 20 years, there was a significant blackout a couple years back, they are just now laying a second line for redundancy.

There will be no new long-haul lines: places that need power, it is too expensive to buy new right of way. Old lines can be doubled or up-volted on the same route, but that trick is ancient and can only go so far.

That's the obvious things. The short-term problem is that many of the controls for distribution are both dumb and easily hacked by strangers anywhere in the world. One confused relay caused the great northeast blackout of 2003... if some hacker found the right 2 or 3 relays and caused heavy damage it might take much more than 12 hours to sort it out.

> personal wind turbines and it's just not feasible for me right now.

This plan can be assembled mostly from junk parts:

6 volt windmill for farm light, N. Dakota Ag College and USDA, 1935:
  http://www.ag.ndsu.edu/aben-plans/d43-1-1.pdf

Using 12V alternator and batts instead of 6V is trivial.

BUT.... I computed my electric bill. Assuming I had wind most of the time, I would need twenty seven of these to negate my electric bill. Modern life uses MUCH more power than an off-grid farm in 1935.

I could get an alternator from Jimmy's shed, pipe from George's pile, but 27 alternators may be all the scrap alts in town.

Alternatively a rotor with 27 times the area, about 5 times longer, 25 feet diameter. You don't mount such a whirrly-gig on a pipe on a stump, not when we sometimes have wind that downs trees. Also an alternator 27 times bigger than a car's is not a scrapyard item.

That's if the wind blew. Here we have over 10mph less than 5 days a month. Today was so still, the dandelions shed straight down.

Using solar for A/C is fairly smart (not as smart as locating where the sun don't shine so hard). Peak load is also peak supply. However converting to electric at 4% efficiency, then converting electric to coolth at no better than 70%, is round-about. A simple ammonia rig could take heat directly and make cold. No moving parts (except fans to distribute the cold). But non-mechanical refrigeration has been out of style so long, we've forgotten as much as we ever knew.

> It depends on where you live, too. Here in Las Vegas

Well, that's easy. Move to Maine. A/C cost is less than 1% of my electric bill. Many many folks don't have A/C. Yes, the oil truck has to fill me up every month in winter, and I was still burning a bit in June.

[Paul Marossy]

Using solar for A/C is fairly smart (not as smart as locating where the sun don't shine so hard). Peak load is also peak supply. However converting to electric at 4% efficiency, then converting electric to coolth at no better than 70%, is round-about. A simple ammonia rig could take heat directly and make cold. No moving parts (except fans to distribute the cold). But non-mechanical refrigeration has been out of style so long, we've forgotten as much as we ever knew.

> It depends on where you live, too. Here in Las Vegas

Well, that's easy. Move to Maine. A/C cost is less than 1% of my electric bill. Many many folks don't have A/C. Yes, the oil truck has to fill me up every month in winter, and I was still burning a bit in June.

I would love to move to Maine, but that will never happen. We don't know anyone there or have any family there. And no company is going to move me there because what I do for a living isn't necessary there. Well I could design heating systems but I'm sure probably that's a 95% contractor driven thing over there. And I'm not a P.E.

Anyway, they phased out ammonia chillers a while ago now, but they were pretty effective machines in their day. Interesting idea to have an ammonia based device with no moving parts.