What is the benefit of having 220V circuit compared to a 120V circuit? Is it the amount of current being used?

 

I'm by no means convinced that there is one. Some will say that higher voltages can be transmitted with lower loss, but that only effects the utility not the consumer. At the plug power is power: 120 VAC @ 1 Amp is the same power as at 240 VAC @ 0.5 Amps. You tell me what the difference is.

 

Some argue that with the fact of higher voltage needing lower current, that you can save some money by using smaller wire in a home or business. I don't know what the actual savings on that would be, but I have to doubt that it would be very significant.

Where you really get an advantage is using 3 phase power versus single phase. With 3 phase you can get much more work (HP) out of a much smaller motor, with less heat loss, etc. 3 phase is simply more efficient any way you look at it.

Anyway, to my main point, which is that I agree with Papabravo, when it comes it 120/240 I don't see much of an advantage to one versus the other. We use what we use because its what we have used....

 

What is the benefit of having 220V circuit compared to a 120V circuit? Is it the amount of current being used?

You may be interested in looking at a similar question posted recently here at AAC: http://forum.allaboutcircuits.com/showthread.php?t=3881

Dave

 

I remember reading somewhere that one is more prone to cause fires and the other electricution. Not sure which is which though or if that is even true.

 

an alternator spins, if you have 3 generating coils then 1 rev = 360/3=120 degrees, can you spot somthing here, 1 complete ac cycle goes from zero volts up to 120 volts back down to zero and then down to -120 volts, three coils are arranged around the circumference of the alternator, each one subtends an angle of 120 degrees, as a result 3 distinct sinusoidal waveforms produced with a displacement of 120 degrees, nice and easy to build, british always manage to be awkward,for reasons i dont yet know u.k used 240 volts at 60Hz, and later reduced this to 220 volts at 50Hz so as i understand the alternator speed was reduced from 60 to 50 rpm or multiples therof

 

Peak voltage is SQRT(2)*RMS_VOLTAGE. Did that fact escape your notice.

 

Here's a info tibit you:

(f x 120) / P = RPM

f = frequency
P = number of poles on the generator
RPM = generator speed.

My three phase four pole generators ran at 1800 RPM.

In a western state, I've seen 220 lines up to about 245 rms volts. My lineman neighbor said that was within normal parameters for that line.

 

In the US, 110, 220 and 440 VAC are about the minimum line voltages; 120, 240 and 480 V RMS are more the normal voltages, at least today. I don't know what they were, say in the '50s and '60s.

Also, one comment that wasn't directly addressed is that, because higher voltages deliver more power than lower voltages with the same current, larger motors and heating appliances [i.e., electric clothes dryers and stoves] are built to run on 240 VAC. This seems to be the case in larger factories I've worked in, too; all the machines run on 480 V, three phase [except for motors larger than about 500 hp; many of them run on 4800 V].

 

There are economic advantages for the consumer using 220v vs 110v.for a given installation using 220v your main switch can be rated at 0.5 that required for 110v.your outlets and switches can be rated lower as the cable.,where on a110v you can only use 1-13amp outlet on a 15amp.cct.with a220v you can use 3-5amp on a15amp cct.

 

.......british always manage to be awkward,for reasons i dont yet know u.k used 240 volts at 60Hz, and later reduced this to 220 volts at 50Hz so as i understand the alternator speed was reduced from 60 to 50 rpm or multiples therof

I can't recall the UK ever using 60Hz. All the early power stations generated DC because the tramways they were built for used 220V DC motors with regenerative braking. The supply was then extended to include a service to domestic users. Main distribution used 3 wires, ie. +220V, a 0V neural, and -220V, so each alternate house in a street had +220V or -220V as its 'hot' wire.

I believe that when the supplies were changed to AC in the middle of the last century, 50Hz AC was used from the outset.

 

I can't recall the UK ever using 60Hz.

I concur, I have never heard of the UK using 60Hz and would be interested in seeing evidence to contrary.

Dave