Energy Why do we have dual voltage in North America?

I was reading about a guy having issues with his water pump wiring (on an unrelated forum), earlier tonight. So many thoughts ran through my mind, regarding wiring everything from lights, to fans, to clothes dryers, to welders, and - to water pumps.

I was just curious if anyone knew (self admittedly, I have done nil research on the subject) why we have some appliances run on 120 vac, while others are on 240 vac.

You see, every country I have resided in, outside of the US, has run single mains power between 220 vac and 230 vac. All but one is powered at 50 hz. This includes, but is not limited to, Australia, New Zealand, Thailand, Philippines, and Cambodia. That's it, single voltage, period. (I think limited areas of the Philippines may have split voltage, due to the US bases that were previously in country.)

I'm just wondering why, if anyone may know or feel free to speculate, the US never went with single voltage mains power? I have yet to see drawbacks. But, some pluses that came to mind are:

1. No worries of having to balance the load panel in your home.
2. No special circuits needed for specific "high drawing" appliances.
   
3. Lower ampere draw, due to higher voltage, which leads to #4.
   
4. Smaller wires to provide higher voltage power.
5. Higher efficiency of power use?

Personally, I just do not see the logic in having a dual voltage system. So, I hope someone can explain this to me.

 

Because, that's the way that felonious old hack Thomas Edison designed it, after stealing Nicola Tesla's patents.
Also, 110VAC is a bit safer. In electronic tech school, an instructor told us young squids, "110VAC give you a buzz. 220VAC knocks you on your butt. 440VAC knocks you across the room!"

 

@Asia-Off-Grid Like you, I spent entire adult life overseas and even though I've been to over 50+ countries, and they've always been 220V which, when you think about it, seems to be a better system (reference your 5 points/bullets) - so - like you, I have scratched my head and asked the same damn question over and over again thinking small light bulb would come on or someone, somewhere would be able to give me some sort of answer...but no-joy.

I have chalked this up to 'this is the way it has always been and the way it will stay' sort of like why we never embraced the metric system which is a much easier and logical system but at least with the metric system I think I got an answer which might be the answer to the Voltage also...money. It would cost to much to change the tooling and etc. Hell, just to change the road signs would cost a fortune. So...that is my best guess but please let me know if you ever find out

 

I thought he would have preferred to power everything in DC voltage, no? We all have to admit, his battery technology was lifetimes ahead of others.

Yeah, we pretty well screwed the pooch on that, as well. I wouldn't go back to the US standard if I were paid to do so. Metrics is far easier to deal with. Calculations are fast and simple. The metric system is probably used in science and medicine, for similar reasons?

 

Why was part of the US on 25 Hz power for many years?

 

Edison was a sore loser so once he knew DC was finished he used what money he had to hire a ton of lawyers and legally steal many of Westinghouse and teslas patients.
At that time tesla and Westinghouse were very low on funds and hadn't made wise business decisions so were ripe for the picking.

 

Niagara Falls still generates power st 25Hz. It's actually better suited for long distance transmission than 50 or 60Hz power.

 

Re: #8. I was taught that transmission efficiencies increased with higher voltages and higher frequencies. Has to do with lower I squared R losses. That is why D.C. was left at the gate. Look at Ohm's law. You have a 1kw, 120vac load (non inductive). Feed it with an xfrmr across a 480vac service. 1000w divided by 480vac is < 3 amps. Secondary can supply > 8 amps. As frequency increases current flow also behaves differently, and the Litz or skin effect takes hold, whereby it flows increasingly near the surface of the conductors. Smaller wire size=less copper=cheaper.

 

Very high voltage DC transmission has always been possible.
Not that you could do anything with it on the other end.
The difficult part was transforming the DC back to AC. That wasn't even really possible until the 1960 late or 1970.
Then it was still cost prohibitive until the 1990s.
Now it's fairly common.

 

We use 120 Volts AC for "house current" in the U.S. because it's the voltage that Edison set at his direcxt current generators, to power lightbulbs when he first wired parts of major cities. None of the businesses or homeowners wanted to change all the light bulbs or wiring when Alternating Current became the norm, so we're stuck with more-or-less the same voltage that Edison used.

It's worth noting that "120 Volts" is a nominal figure: the actual voltage varies widely during a typical day, and can dip to below 110 volts, or climb above 125 on rare occasions, as the grid deals with varying loads caused by air conditioning, elevators, electric stoves, and electric heating and ventilation in addition to the usual TV sets, computers, and other appliances.

N.B.: The figures given for the voltage of our AC outlets is the Root Mean Square (RMS) value, which is the figure that would create an equivalent "heating value" for the same DC voltage: in other words, we use 120 Volts AC because it will produce the same heat in an electric stove as 120 volts DC. The actual value of the alternating voltage will vary between zero and 340 volts peak-to-peak.

 

For lower voltage DC to AC yes rotor converters were widely used but I don't think it's ever been practical to do utility scale with a rotor converter using DC input power at 10,000s or 100,000s of volts.

 

But but but... why did the world not go with 60 cycles (Hz), but they choose 50... why not 100, i.e. metric, 60 is understandable 60 seconds, 60 minutes... or why did they not go metric with time, i.e. 100 seconds per minute, 100 minutes per hour, 10 hours per day... I understand a foot, it is after all a "FOOT", and an inch is your index finger from the first joint to the second... easy to use, always with you, you can never, well almost never lose your measuring tools. Instead they go with the Meter, which is supposed to be some measurement of the earth at the equator, at noon on the second day past the summer solstice, on a calm day with the moon in recession... and it's not even correct.

I'm glad my beer growler has a 38mm cap, at least it's the same size as that old clumsy 1-1/2" cap... and don't get me started on plumbing and whatnot!

Rancher

 

Brother, you are preachin' to the choir!

The typical voltage at the power points here, should be 230vac. But, it can drop to well below 100 volts, without completely dropping out. Maximum high voltage, typically, is around 240vac. Below, you will see one of several neon lamps that are connected at breaker panels and main disconnects throughout our system, to let us know when mains power is connected.

I took the image at night, due to it being much easier to see the neon lamp illuminated.

Too often, the brightness will vary, as though someone has it wired to - and is adjusting a potentiometer up and down. Talk about voltage variances that will destroy your appliances! The limit the neon lamps drop out at, is 96 vac.

Fortunately, our Inverter equipment (air-con and refrigerators) have circuit protection built in, so they will not reconnect the compressors until 5 minutes have passed since the last cut, or major drop in voltage.

Actually, today, we have run the generator for a total of about two hours (thus far), due to voltage dips and cuts. It's never boring, living in Cambodia!

 

I like 240v stuff.
I have 240v 9 inch grinder, all my air compressors larger than 1hp are 240v, I still have my 240v German microwave, all my T5 and T8 florescent lights have universal voltage ballasts and most run on 240v, welder, plasma cutter, I even found a 240v battery charger for 12v batteries.
At my rental house I installed 240v powered split a it conditioners.
My electric car charger uses 240v.

 

Back when Edison was filching the patents of others and having his team make them economically useful, the old curmudgeon would take camping vacations with Teddy Roosevelt, Henry Ford (who supplied the House Cars, early RVs) and a couple other deep pocketed movers of society. These powerful men (barstages all) were the ones who set national policy, including our early electrical grid system.
Tesla invented AC current, and had wanted to use wireless transmission to bring free power to the world. The Big Guys were set on making profit from supplying power. Easy to see how things worked out, the way it was directed by those in government and industry. History is full of interesting info.

 

LOL. I was hoping it was an image of all three, alive, together. I was going to ask if you took the photo.