220 v - 240 v 50 hz versus 110 v 117v 60 hz power.

[Anonymous]

I understand but the overall voltage is still pretty low, I didn't understand how they di d that before, I thought they brought in a a neutral and just shared thatneutral over two phases!

Ths Ian

[Anonymous]

I've heard of people that have died when working on the 12 VDC system in their cars. The battery acid on their skin, combined with a firm grasp of the car frame and tools got them. Don't think that just because it's "low voltage" doesn't mean that it's completely safe.

It's only safe if it's grounded.

As for the single-phase residential vs. the discussion on three phase, I can cover both bases!

Residential loads are 99.9% single-phase in nature here in the US. It's tfed from a 240 volt transformer that's centert tapped (120 volts), hence the 240/120. All of the nomenclature for 120 or 117 or 110 volts just indicates at what voltage is "nominal" or the "minimum" for the equipment. In reality the ANSI standard is anything between 126 and 110 volts at the outlet is fair game for the appliance.

For three-phase customers you have several possibilities. Medium commercial loads and large apartment buildings will typically take 208/120 volt grounded-WYE service. Larger or heavy industrial customers will often take 480/277 volt Grounded-WYE service. In these two cases the transformer windings are shaped like a wye, with the neutral grounded.

You can also get in some areas a three-phase 240/120 delta, where you have three 240 windings built into a delta with one of the windings center tapped and grounded. This will give you a 240/120 single-phase service which is typically used for lighting and office use, and 240 delta to drive the three-phase equipment. Most 208 V three-phase equipment can be powered from 240 delta. Gas stations love this service as everything they have is 120 or 240, except their air compressor which is three-phase.

Mark in Utah

[Anonymous]

The flicker at 68 does seem weird. Lot of studies done when cinema (movies, that is) were being developed and they settled on 24 fps with each frame shown twice to eliminate flicker.

But fluorescent lights seem to have a different 'bent'. If you look through plate glass, at night, at a display window lit by fluorescent bulbs and hum at just the right frequency, strange effects occur. Humming at multiples of 60 cycles is necessary. Bring a tuning fork.

As far as voltage, frequency, and rigor mortis, i.e. death, it takes - from what I've read - only 75 milliamperes (0.075 amps for the decimally challenged) to initiate coronary fibrillation which shortly leads to short of breath, like death. Have wondered for years how this data was collected. Where did they get the volunteers? It should be noted that 1.5 volts can supply 75 milliamperes through a low enough resistance like the blood stream. Anybody know the resistance of blood per foot?

Art

[Anonymous]

I'll get you for that remark Troy!

That thing about getting flicker at 68 cycles was very interesting and it should not happen, maybe its to do with the wve form not the frequency?


Rgds Ian

[Anonymous]

just a point of interest when i worked for the us navy in the 1960's and 1970's the navy jets used A.C. at 400 hertz or cycles per second it made for realy small powerful electric motors the higher the frequency the less iron required glennbob[bow][bow]

[RhB_HJ]

QUOTE: Originally posted by troybetts

It all hurts.
Stay clear of a dead topic.[:)]

What do you mean "dead"??
You apply anywhere from 50V upwards and things are bound to be real lively.[;)][}:)][}:)][:)][:)]

OTOH since most of us will not influence the voltage or cycle frequencies supplied to our households i.e. we plug it in, it works, Hurray!! I guess it is a dead topic. [8][8][8]

Of course we could be discussing the relative merits of using solar panels to run our trains vs. using a stationary bicycle coupled to a generator vs having a waterwheel or windturbine for the same purpose.

Or people in zones with a lot of lightning strikes could speculate on the most efficient method to store all that energy to have a perpetual motion (or nearly so) GRR. [;)][;)][:)][:D][}:)][:D]

[Anonymous]

It all hurts.
Stay clear of a dead topic.[:)]

[Anonymous]

Ian, unbalances in the US 120/240 system do occur. Back in NY, I noticed in a friend's house that every time the furnace went on the front room lights got brighter. Undoubtedly the neutral wasn't up to the task and the furnace was on the other leg of the input line.

[tangerine-jack]

I've seen absolutely the worst generators ever, US Army issue 24V 45 cycle 3kw. Ever been in a disco? Want to talk about light flicker and distortion? After a few minutes my eyes started hurting. I'd much rather use an onboard vehicle generator or a flashlight than one of those 3k POS. The new ones are much better, not a flicker or phase to be seen, and enough juice to run your lights, computers, TV, coffee pot, AC, and recharge a cell phone (not authorized of course) but we don't get one of those, that's for the General[:(]

I've never noticed a flicker in my lights at home, only in some industrial settings and even then it was due to poor maintenance I'm sure. In any case, we are all forced to use what the utility company sells us, we just have to make it work.

[oX)]

[Capt Bob Johnson]

Dunno as I'd go along with that! I have 20kw emerg generator that exercises about an hour each week. because of computers and other electronics being able to tolerate over frequency better than underfrequency it came from factory set at 68 cycles and flicker on incadesent lights was horrendous! While we adjusted it down to 62 cycles it stlii has noticible flicker, but not enough to hurt the eyes. That's my 2 cents.

[Anonymous]

Yes well when you get into three phase power as we have it here in Australia, you have 240 V to neutral and 415 V between each phase. If you have a star configuration you have a neutral but in delta you do not have a neutral.

When I was in supplying fluorescent ballsts; sometimes in a big building in the city the phases would get out of balance when the building was first being set up and you would get hellish current in a very small neutral conductor that really should not have much going through it at all.

Then as buildings got bigger and bigger and more and more fluorescent lighting was used a new thing (back in the sixties new) called harmonic distortion which only seemed to affect the odd harmonics ie 3, 5 and for some reson particularly 7. Horrific neutral currents also occured under these circumstances as well. It seems the worse the ballast the better the harmonic distortion was.

So I can see that the American system of only having two phases each of 115 V must have its drawbacks.

The main thinhg I wanted to discuss was upping the frequqency I'm sure it will have benefits not just to do with flicker which mainly affects your perifery vision anyway.


Rgds Ian

[Anonymous]

Hadn't thought about that, HJ, and as long as everything is insulated or isolated and fingers crossed to ward off failures, it should work. Would hate to replace a 220 volt bulb on a EU setup over here, though.

Art

[RhB_HJ]

QUOTE: Originally posted by artschlosser

The 220 volts for use in stoves, pumps, etc is available because of the 3 wire feed to the house. The red wire is 110 meaured from the white (the neutral) and the black wire is also 110 meaured from neutral.
But from red wire to black wire, there is a 220 volt difference; the red and black feeds are 180 degrees out of phase.
I've rented houses where the kitchen's two socket outlets would have one wired to the black and the other wired to the red. If two appliances connected to this outlet both had a 'live' spot on them, you could really get shocked touching both at the same time. Not good practice.

George Westinghouse was also in on the electric chair thing. He was adamantly against it as he thought it would make the public reluctant to switch from gas lighting to electric lighting.

And after much reading through the years, I am quite convinced that it is DC that locks one's muscles but the altenating aspect of AC does not cause a lock up. But I will happily let some one else verify this.

I've been to England where 50 cycles is in use and was not bothered by flicker (motion pictures have a 48 cycle flicker rate) but way back when visiting Canada, the 25 cycle AC in use at that time had a decided flicker.

Art
Art

Art,

The above wiring scheme is what saves many a European's frustration with certain small appliances that are not available in NA.
The savvy user wires a special transition harness - making absolutely sure "things" are properly grounded - and gets to use all the "Stuff" from EU. Always keeping in mind that there could be premature failure due to the 60Hz here in NA.
The rule of thumb is: "Lets hope it lasts long enough for the NA market being served/supplied with the same nifty gadget" [;)][:)][;)]

[Anonymous]

There's an interesting story related to the 50hz - apparently the WW2-era "Chain Home" RDF (later radar) network used a pulse rate derived from it. Result being that an attempt by Germany to take a closer look (using a Zeppellin airship stuffed with recievers) was a complete flop - they either looked in the wrong frequencies or thought the pulses they were picking up were some weird electrical noise from the mains power supply!

[Anonymous]

The 220 volts for use in stoves, pumps, etc is available because of the 3 wire feed to the house. The red wire is 110 meaured from the white (the neutral) and the black wire is also 110 meaured from neutral.
But from red wire to black wire, there is a 220 volt difference; the red and black feeds are 180 degrees out of phase.
I've rented houses where the kitchen's two socket outlets would have one wired to the black and the other wired to the red. If two appliances connected to this outlet both had a 'live' spot on them, you could really get shocked touching both at the same time. Not good practice.

George Westinghouse was also in on the electric chair thing. He was adamantly against it as he thought it would make the public reluctant to switch from gas lighting to electric lighting.

And after much reading through the years, I am quite convinced that it is DC that locks one's muscles but the altenating aspect of AC does not cause a lock up. But I will happily let some one else verify this.

I've been to England where 50 cycles is in use and was not bothered by flicker (motion pictures have a 48 cycle flicker rate) but way back when visiting Canada, the 25 cycle AC in use at that time had a decided flicker.

Art
Art

[tangerine-jack]

Ian's quite right about that, remember the Tesla vs. Edison battle way back when?

"DC is dangerous, look I'll prove it by building an electric chair to execute people with, whereas my AC is quite safe so I will build a 250,000 volt coil and you can touch it safely"

Well, it went something like that anyway..............


[oX)]

[Anonymous]

That business about 220 V throwing you is quite wrong. DC may expel you but AC causes your muscles to contract hence you appear to be holding on wether you want to or not.

Rgds ian

[Anonymous]

Ah - I was wondering if it might have that sort of problem. I have some experience of dealing with 12v electrics in a camper but always assumed the voltage sag was due to the battery not being able to keep up. Ah well, back to the proverbial drawing board!

[Anonymous]

Not so good mate, the I 2 R (eye squared R) losses are horrific.

Rgds Ian

[Anonymous]

We have 230v - not sure I'm inclined to check it for its ability to throw me across the room! I would say that it's just as safe as 110v in normal use, both are going to do you harm if you attempt to rewire the house without knocking the circuit breaker off first. What annoys me is that I have so many devices that have to take the domestic mains power then put it through a transformer (most electronics work like this). How about a 12v or 24v DC ring main for houses that would use one big transformer to provide a stabilised output? Would this have any benefit in terms of saving energy? It just seems daft to me that everything has a seperate transformer rather than having a single unit and a ring main supply. Waste heat from a single transformer could be used to help heat water too.

[Puckdropper]

From what I've heard, 220 and above will throw you away while 120 will grab you. I know 120 will grab you from experience, but have not done anything w/ 220 to see.

220 may be a "safer" voltage if electrocution is a consideration...

[Anonymous]

No

[tangerine-jack]

Hey Ian, does your loo flush anti-clockwise also during a solar flare????[:D]



[oX)]

[markperr]

All's I know is when I was stationed in Japan back in the 70's, the power was 100 volt/ 50 Hz. Incandescant lights flickered horribly. The naked eye could almost be trained to to count a sub-harmonic in the flicker. It was like staring at a very low powered strobe light.

In all honesty, though, for residences in North America, the average distance run at 110 volts is only a hundred feet or less, since voltage coming into the residence is 220/240V and then the 110 lines are tapped off in the main panel.

Mark

[Anonymous]

You are right Mark 240 v will knock you around more.

In my time I have had many electrical shocks but the worst one I ever had was from 50 V DC. I had to go to hospital for observation. However it wasn'r one shock i had about three one after the othr. I still think I may have got a capacitor discharge as well.

It was to do with a Sola UPS in Sydney CBD.


With regard to the solar flares if you have a radio link involved as does MTS it will make your trains run backward and cause reversing loops to run anti clockwise when they should be clockwise.

Rgds Ian

[Anonymous]

Pro's and cons:

Higher voltages transmit power further with less power loss and less voltage drop.
Lower voltages require less insulation (a factor in motors), are cheaper to build ight bulbs, and is safer for leakage currents (fewer problems when insulation goes bad).

Higher frequencies require smaller transformers to handle the same amount of power.
Lower frequencies require slower moving equipment, which means it'll last longer, and makes standard single pole motors run slower.

A "standard" single-pole AC motor will operate just under 3600 RPM at 60 Hz, and just under 3000 RPM for 50 Hz.

220 volts will bounce you off the wall harder.

Mark in Utah

[RhB_HJ]

QUOTE: Originally posted by tangerine-jack

Ooooh, good point, HJ. Maybe we can link this over to the UV thread, sounds like we're touching on the Universal Theorum here by linking all physical laws. Wow, an age old question solved in the garden! Do you suppose we should all go live-steam just in case?[:P][;)]

[oX)]

[:D][:D][:D]

Going Live Steam would get us out of the loop of the loopy electrons,[;)][:o)][;)] but who is to say that would be safer? Once the research starts on the effects of the ozone hole on the relative density of steam due to the "thus far undiscovered Santa rays" the worrying will start all-over.

So while the Universe - including various laws - gets re-jigged; I keep beavering on my projects. [;)][:)]

[tangerine-jack]

Ooooh, good point, HJ. Maybe we can link this over to the UV thread, sounds like we're touching on the Universal Theorum here by linking all physical laws. Wow, an age old question solved in the garden! Do you suppose we should all go live-steam just in case?[:P][;)]

[oX)]

[RhB_HJ]

QUOTE: Originally posted by tangerine-jack

More importantly that all that lab theory stuff is what does a nice 100 trillion gigawatt solar flare do to the ociliscope readings, especialy with that nice big ozone hole over the outback?[}:)][B)]
[oX)]

Jack,

Good question, but more importantly will the GRR trains still run?[:0][:0]