Why 110V grid runs in 60Hz?

[arvinfx]

Totally why 110V? and why 60Hz? what the problem is in 50Hz?

 

[picbits]

A good writeup here on Wikipedia

https://en.wikipedia.org/wiki/Utility_frequency

 

[throbscottle]

That's really interesting reading, but still doesn't explain why half the world uses 110V, the over half 220 or 240V (and to me, the higher voltage makes more sense because you need less copper in the wires)

 

[Timescope]

Thanks picbits for the goldmine of information. We could also ask why some regions use NTSC, PAL and SECAM systems, why some countries drive on the right of the road, others on the left, why there is no standard mains plug , why some people use Mac, others pc etc.

Timescope

 

[throbscottle]

When I was at college, they taught us NTSC stands for "Never Twice the Same Colour"

 

[dr pepper]

Same here throbs, never twice the same colour isnt what it stands for, I think (about to be corrected) it stands for national televison system comittee, they also said at college pal stands for perfect at last.
Pal contains a colourbust signal that calibrates the colour line by line, ntsc doesnt do that and on old tellys the colour went squiffy to the right of the screen and had to be adjusted every so often.

The volatge in the uk at one time differed as to where you were in the country, most of my valve radios have multiple taps for the mains power.
Some say 50hz was a trade off from a diesel engines max efficiency (which is normally 2200 rpm rather than 3000 req for 50hz), and some say its an efficient speed to run a turbine.

 

[MrAl]

Hi,


I agree that 220vac is better than 120vac because the wire diameter to deliver the same power could be smaller, smaller by close to 26 percent less diameter. That means the 220vac wire could have a diameter about 0.73 times that of a 120vac wire, which of course is smaller and means less copper material to deliver the same power.

In fact, an immediate upgrade to the grid in the USA could be realized if the voltage was turned up to 220vac because the whole grid would then be able to deliver at least 83 percent more power with the same wiring. Trouble is, all the transformers would have to be changed too...which is a big undertaking.

Yes 120vac is safer than 220vac, but that's the only good point i can think of. It's still dangerous though.

I'd gladly throw out all my clocks and buy a transformer or two to power 120vac devices if i found out tomorrow that the USA was converting from 120vac 60Hz to 220vac 50Hz. No problem as i would welcome the boost in power for devices.

I like 50Hz a little better than 60Hz because it makes a neater graph on paper/computer plots

 

[Nigel Goodwin]

Same here throbs, never twice the same colour isnt what it stands for, I think (about to be corrected) it stands for national televison system comittee,

I thought 'standards' rather than 'system'?.

they also said at college pal stands for perfect at last.
Pal contains a colourbust signal that calibrates the colour line by line, ntsc doesnt do that and on old tellys the colour went squiffy to the right of the screen and had to be adjusted every so often.

Both contain colour bursts - and PAL is just a simple improvement on NTSC (they are very similar otherwise).

PAL stands for Phase Alternating Line - the problem with NTSC is that the specific colour is dependent on the PHASE of the signal, so if the phase changes, then the colour does as well (this is why NTSC TV's had Tint controls - to make the colour something like correct - and PAL sets didn't, as there was no need). Essentially PAL sends each alternate line of colour inverted, this is passed through a 64uS delay line and 'mixed' with the previous line this cancels out any phase errors, ensuring correct colours irrespective of phase errors.

America was stuck with a poor system because they 'did it first' (rather like the UK with 405 ), the technology for PAL probably didn't exist when NTSC was designed, and of course they didn't have a few years of 'beta testing' to fall back on, as Telefunken did with NTSC being the 'beta test'

The volatge in the uk at one time differed as to where you were in the country, most of my valve radios have multiple taps for the mains power.
Some say 50hz was a trade off from a diesel engines max efficiency (which is normally 2200 rpm rather than 3000 req for 50hz), and some say its an efficient speed to run a turbine.

The Wikipedia article linked above seems quite helpful - and of course many radios and TV's were AC/DC as well as multi-voltage, because some mains was DC.

Not far from me there was a private mains system (until 'relatively' recently), where a local large company (Staveley Works) provided power for much of the town is was part of, at 25Hz or so I believe?.

 

[crutschow]

When I was at college, they taught us NTSC stands for "Never Twice the Same Colour"

And that SECAM stands for "Something Essentially Contrary to the American Method".

 

[Nigel Goodwin]

And that SECAM stands for "Something Essentially Contrary to the American Method".

That's the French for you

 

[crutschow]

Hi,


I agree that 220vac is better than 120vac because the wire diameter to deliver the same power could be smaller, smaller by close to 26 percent less diameter. That means the 220vac wire could have a diameter about 0.73 times that of a 120vac wire, which of course is smaller and means less copper material to deliver the same power.

In fact, an immediate upgrade to the grid in the USA could be realized if the voltage was turned up to 220vac because the whole grid would then be able to deliver at least 83 percent more power with the same wiring. Trouble is, all the transformers would have to be changed too...which is a big undertaking.

...................

Not sure I understand your statement. The USA grid wouldn't change since it operates at a much higher voltage. And most US homes already have center-tap 240V going to the junction box from the neighborhood transformer. 120V is provided by going from one side of the 240V to the center tap. So the problem would be changing all the zillions of appliances from 120V to 240V.

 

[Mr RB]

...
I agree that 220vac is better than 120vac because the wire diameter to deliver the same power could be smaller, smaller by close to 26 percent less diameter. That means the 220vac wire could have a diameter about 0.73 times that of a 120vac wire, which of course is smaller and means less copper material to deliver the same power.
...

I prefer to think of it as "using double the voltage means you can use HALF the amount of copper in the wires". That's a big saving from 240v to 120v.

There's a few other benefits probably in there, like 240v power tools can have a higher shaft power per frame size than 120v power tools.

120v has benefits, it is many times nicer to get shcoked with, 240v is quite nasty! Also with the modern age of everything (TV's PC's etc) all running from lowish voltage DC internally I think 120v is superior there as a 120v AC -> low v DC supply is more reliable and more efficient.

 

[throbscottle]

Not sure I understand your statement. The USA grid wouldn't change since it operates at a much higher voltage. And most US homes already have center-tap 240V going to the junction box from the neighborhood transformer. 120V is provided by going from one side of the 240V to the center tap. So the problem would be changing all the zillions of appliances from 120V to 240V.

I'm confused. Does this mean if you connect a live wire from one socket in your house, and a live wire to another socket in your house (or maybe your neighbours house), you get 240V?

In the UK we have a 3 phase supply to the local transformer, and neighbouring houses each get a phase (so between me and one of my neighbours, we should be able to get 450V between my live and their live)

 

[Nigel Goodwin]

I'm confused. Does this mean if you connect a live wire from one socket in your house, and a live wire to another socket in your house (or maybe your neighbours house), you get 240V?

Not exactly - they use a bi-phase system from a centre-tapped transformer - so a house will generally have 120V sockets (for low power items) wired from neutral to one live. It will also have 240V sockets (for high power items - cookers, heaters, air-con etc.) wired from live to live. Think of it like a transformer in an amplifier, you use a centre-tapped transformer to give +/-xx volts, which gives you the choice of xx volts (using one tap) or 2xx (using both).

 

[throbscottle]

Fascinating. Goes back nicely to the o/p's question of why we do things in different ways. So US houses have 2 live wires? Huh, strange!

 

[Nigel Goodwin]

Fascinating. Goes back nicely to the o/p's question of why we do things in different ways. So US houses have 2 live wires? Huh, strange!

It's even more strange - America commonly used aluminium wiring rather than copper at one time now that is nasty!.

 

[canadaelk]

The power grid and all those nice things were developped in the early stages of technology and communication. Pal is not better (for the most part) because it is newer than NTSC, but because of the 60 Hz. Colour TV uses interleaving technology. The higher the mains frequency, the more lines (sharper pix) you get. I have no idea how they made the telephone system work internationally (hm, maybee they talked to each other? pun!)

The reason the English drive on the left is a holdover from Roman times: as most people wher right-handed they would use their right arm/hand for a weapon for attack or defence. Napoleon (there go the French again) wanted it differently and we now drive on the right. The same he did with introducing metric. And than, oh God, the Germans standardised it. E

 

[canadaelk]

Nigel, when I was a kid in Germany, shortly after WW2, we had aluminium wiring (the copper was torn out for the "war effort") and they just started to switch from 150 VDC to 220 VAC (now 230). E

 

[throbscottle]

It's even more strange - America commonly used aluminium wiring rather than copper at one time now that is nasty!.

I was told by an electrician recently that aluminium wiring was sometimes used here in the 70's when there was a copper shortage. Presumably the same reason goes for the US.

 

[jpanhalt]

I'm confused. Does this mean if you connect a live wire from one socket in your house, and a live wire to another socket in your house (or maybe your neighbours house), you get 240V?

Yes, that is correct. The two phases (relative to neutral/grounded wire) can go to different outlets in the same house. One could get 220V across the two powered lines (usually black in the USA). It is a well known shock hazard. When I have multiple pieces of electronic equipment working together (e.g, computer, strip chart recorder, monitor, spectrophotometer), I take the precaution of being sure they are on the same phase. Strip chart recorders, in the days when they were used, were particularly sensitive to being on a different phase than the device generating the signal to them.

On the plus side, if you randomly touch one of our wires, you only have a 1/3 chance of getting a shock. Some electricians recommend putting the third (ground) connector on top rather than on bottom for wall sockets for the same reason. I don't think that is a very strong argument.

Another plus is that in a storm, you may lose only one of the phases. Thus, any 110V appliance on the other, live phase continues to work. That is quite a common occurrence in an older neighborhood with overhead power lines. Of course, 220V appliances (usually electric ranges, air conditioners, and cloths dryers) will not work.

John