120v vs 240v?

[orangecat]

Why are voltages and frequency different in some places in the world? What's the point other then making some electronics incompatible. Was there a good reason for this?

[unidentical]

standards just developed differently in different places. The only reason they don't change it all to one is that it would be far too much work to bring the whole world in to line with a standard. There's no practical way to do it.

[LDX]

Based on this article US homes have 240v going into their panels

the real reason why US is 120v is because 240v was not available 

at the time that electrical service was implemented. 

 

other countries took their time to implement it, and they got 240v 

 

http://wiki.answers.com/Q/Why_does_the_US_run_at_120V_when_some_of_the_world_runs_at_240V

[fishymamba]

Our house has 240V lines, our over and A/C use 240V. But you would have to be pretty hard core to run a 240v line just for your PC lol.

[LegendKillerRG]

Is 120v stronger/better or is 240v stronger/better or are both the same thing?

[aj101202]

Is 120v stronger/better or is 240v stronger/better or are both the same thing?

 

i think 240v is more power efficient 

[Rudel]

In a sense, 240v would be better because the equipment can draw less current. 

[the_devil52]

In a sense, 240v would be better because the equipment can draw less current. 

 

Actually I think it would draw more current. I = V/R Therefore assuming constant resistance, a higher voltage = a higher current.

[Rudel]

The more volts you have the less current you need to achieve the same power.

[mr moose]

Actually I think it would draw more current. I = V/R Therefore assuming constant resistance, a higher voltage = a higher current.

other way around.  P=VxI therefore to get the same power from a 120v power point as a 240v point you have to draw twice as much current.

 

Standard outlets in Aus. are 240v 10amps.  This gives us 2400Watts from the point. if the voltage was 120 then you would need to draw 20amps to get 2400Watts.

 

What this means in real terms is that we can run more appliances of each circuit in the house before the current draw becomes  dangerously large.

[Rudel]

^

 

It's the reason why our (USA) Ranges, Washers, Fridges, etc run off 240v.  It requires less current and safer on the load or wires.

[the_devil52]

other way around.  P=VxI therefore to get the same power from a 120v power point as a 240v point you have to draw twice as much current.

 

Standard outlets in Aus. are 240v 10amps.  This gives us 2400Watts from the point. if the voltage was 120 then you would need to draw 20amps to get 2400Watts.

 

What this means in real terms is that we can run more appliances of each circuit in the house before the current draw becomes  dangerously large.

 

Start with the formula V = IxR

Divide both sides by R

V/R = I :D

[Guest]

i think 240v is more power efficient 

It isn't. Power efficiency in that form would come from the wiring and its makeup. 

[mr moose]

Start with the formula V = IxR

Divide both sides by R

V/R = I :D

 

ohms law is only applicable here if you have a variable voltage source, but we don't so the appliance will be designed to run on a set voltage. so it will draw the smallest current necessary.

 

 

It isn't. Power efficiency in that form would come from the wiring and its makeup. 

 

Actually, 240v is more efficient when running longer power cords but you'd need something like 200Metres of cord before you saw a difference.

[Guest]

ohms law is only applicable here if you have a variable voltage source, but we don't so the appliance will be designed to run on a set voltage. so it will draw the smallest current necessary.

 

 

 

Actually, 240v is more efficient when running longer power cords but you'd need something like 200Metres of cord before you saw a difference.

Actually you'll have voltage drop on a 240v line the same as you would on a 120v line. You'll drop about 3-8v depending on the gauge of the wire - I've had this issue at work. 

[mr moose]

Actually you'll have voltage drop on a 240v line the same as you would on a 120v line. You'll drop about 3-8v depending on the gauge of the wire - I've had this issue at work. 

And with a 3-8v drop from 240v will leave you with more power at the end than if you lost that 3-8v from 120v, yes?  This is why we have high tension transmission lines at 220,000volts, and why in the p.a industry we up the audio voltage to 100 then pipe it around a complex using thinner wires, then use transformers to bring it back down for the speakers.

[Guest]

And with a 3-8v drop from 240v will leave you with more power at the end than if you lost that 3-8v from 120v, yes?  This is why we have high tension transmission lines at 220,000volts, and why in the p.a industry we up the audio voltage to 100 then pipe it around a complex using thinner wires, then use transformers to bring it back down for the speakers.

A 3-8v drop on a 240v appliance is still dangerous. 

 

Just curious as I know you're in Aus, which PA company do you work for?

[mr moose]

I don't. it has been a hobby of mine since 1986.  Live sound and church P.A consulting and installation. I also have worked as IT consultant/sales ran my own electronic repair business back in 92' for all of 6 months before I gave up (inexperience and I bit of more than I could chew).  Have done several courses in electronics. but mostly it is a hobby.  I also  build all my own amps and speakers.

[Fetzie]

A 3-8v drop on a 240v appliance is still dangerous. 

 

Just curious as I know you're in Aus, which PA company do you work for?

All 240V appliances over here are rated at 230V.

Americans use 110V because that is the voltage that Edison found was necessary to create an arc for his carbon electrode lights. Europeans use 230/240V because the Berlin Electricity Board wanted to increase their capacity, and upgrading everybody's lightbulbs from 110V to 240V was less expensive than rewiring the whole city, as you can get higher current with lower amperage if you increase the voltage, and it is the amperage that is limited by the cable diameter. You also get higher efficiency when transporting electricity when you use higher voltages (which is why high-tension power lines run at 220kV and the main-line trains run on 15kV here). The rest of Europe followed suit, and distributed the 230/240V model throughout their colonies, making it the de facto standard throughout the world ... except in America.

Incidentally, the 240V to 12V conversion in power supplies is rather more efficient, to the point that a PSU can easily pass an 80+ certification if plugged in to the wall in Europe and fail the same test if plugged in to a 110V socket.

[mr moose]

All 240V appliances over here are rated at 230V.

Americans use 110V because that is the voltage that Edison found was necessary to create an arc for his carbon electrode lights. Europeans use 230/240V because the Berlin Electricity Board wanted to increase their capacity, and upgrading everybody's lightbulbs from 110V to 240V was less expensive than rewiring the whole city, as you can get higher current with lower amperage if you increase the voltage, and it is the amperage that is limited by the cable diameter. You also get higher efficiency when transporting electricity when you use higher voltages (which is why high-tension power lines run at 220kV and the main-line trains run on 15kV here). The rest of Europe followed suit, and distributed the 230/240V model throughout their colonies, making it the de facto standard throughout the world ... except in America.

 

along with the decimal system :P

 

P.S amps is the unit measurement of current, I think you meant higher wattage with lower amperage B)

[Fetzie]

along with the decimal system :P

 

P.S amps is the unit measurement of current, I think you meant higher wattage with lower amperage B)

We got the decimal system from the French though :/

Yeah, I meant watts.

[mr moose]

We got the decimal system from the French though :/

Yeah, I meant watts.

well it had to come from somewhere I guess.  They probably got it from the gauls who stole it from the arabs. :ph34r:

[sotiris.bos]

240v has less thermal losses. Also the voltage from the powerstation to your city is much higher (in the 100thousands) in order to minimize losses.

[Guest]

240v has less thermal losses. Also the voltage from the powerstation to your city is much higher (in the 100thousands) in order to minimize losses.

Thermal loss?

[mr moose]

Thermal loss?

yes, I am interested also?