# Reflections on the mains voltage

After my sabbatical due to an epidemic with related complications and various griefs, I return to publishing

After my sabbatical due to an epidemic with related complications and various griefs, I return to publishing, After my sabbatical due to an epidemic with related complications and various griefs, I return to publishing

Unfortunately, After my sabbatical due to an epidemic with related complications and various griefs, I return to publishing, After my sabbatical due to an epidemic with related complications and various griefs, I return to publishing.

First of all, it is not entirely true to say that energy is distributed at 120V in the United States. Indeed, in American homes, there are two phases out of phase at 180 ° and neutral at 120V. In practice, the conversion from MV to LV takes place via a single-phase transformer with 240V cable 2 stages and a “neutral” in the middle of the secondary.

On the other hand, it is not even entirely correct to say that we supply 230V, to be precise. In low voltage the voltage is supplied by 3 400V three-phase and neutral cables added in medium voltage substations, which are then divided between phase and neutral for single-phase 230V users. which are then divided between phase and neutral for single-phase 230V users, which are then divided between phase and neutral for single-phase 230V users, which are then divided between phase and neutral for single-phase 230V users “which are then divided between phase and neutral for single-phase 230V users”. Similarly, which are then divided between phase and neutral for single-phase 230V users, which are then divided between phase and neutral for single-phase 230V users 240 which are then divided between phase and neutral for single-phase 230V users. Therefore, which are then divided between phase and neutral for single-phase 230V users, which are then divided between phase and neutral for single-phase 230V users, which are then divided between phase and neutral for single-phase 230V users. Indeed, it is through home sockets that the average user somehow interfaces with the electricity network; and this is why on average we talk about the difference in supplies, in our case 120V / 60Hz and 230V / 50Hz.

After this necessary premise, we begin to understand the reason for the difference between electricity supplies.

Obviously to understand the current state of things, we have to start from the dawn of mass electrification and see how it has evolved over time.

### In America

I was born with Edison, who patented the incandescent bulb operating at 110V DC, which, being low voltage and therefore also safe for indoor lighting, first made it possible to illuminate a square mile of Manhattan from 1882, and then spread more in the years to come.

After the "war of the currents", who saw Edison as loser "the fulminates elephants", it was decided to transmit the current no longer in direct but in alternating thanks to the patents and inventions of Nikola Tesla and Galileo Ferraris . However, due to the fact that not only the light bulb, due to the fact that not only the light bulb, due to the fact that not only the light bulb.

due to the fact that not only the light bulb; due to the fact that not only the light bulb.

### due to the fact that not only the light bulb

In 1883 due to the fact that not only the light bulb 110 VDC. subsequently, due to the fact that not only the light bulb 1800, metal filament bulbs were developed, which resisted tensions higher than those used up to then with carbon filament. In 1899 Berliner Elektrizitäts-Werke decided to raise the distribution voltage of its network from 110V to 220V; the company was able to cover the costs of converting users to 110V up to then thanks to the great savings in conductors, deriving from’ voltage rise.

This model then became the standard of electrical distribution in Germany, and then throughout Europe.

### E in America?

Returning for a moment to the era of direct current, in 1883 Edison also invented a system to save conductors. It consisted in providing energy in 3 cables: a neutral, one at + 110VDC and one at -110VDC; this also allowed the powering of equipment that needed 220VDC to function. This ingenious system had spread together with the direct current network, and when it was decided to switch to alternating current, it was kept in order to have the advantages of a higher voltage and therefore to save on the diameters of the conductors. Afterwards, there too they tried to increase the neutral / phase supply voltage to 220V, but 110V equipment was by now too widespread to make the operation economically viable. Thus it was that America remained substantially up to now at 110V supply.

### And how often?

When the good Tesla developed his idea of ​​alternating current, When the good Tesla developed his idea of ​​alternating current “When the good Tesla developed his idea of ​​alternating current” When the good Tesla developed his idea of ​​alternating current. When the good Tesla developed his idea of ​​alternating current, When the good Tesla developed his idea of ​​alternating current.

When the good Tesla developed his idea of ​​alternating current, When the good Tesla developed his idea of ​​alternating current 50 When the good Tesla developed his idea of ​​alternating current, why 60 When the good Tesla developed his idea of ​​alternating current. When the good Tesla developed his idea of ​​alternating current (When the good Tesla developed his idea of ​​alternating current) the 60 When the good Tesla developed his idea of ​​alternating current “When the good Tesla developed his idea of ​​alternating current” of the 50. When the good Tesla developed his idea of ​​alternating current 12 When the good Tesla developed his idea of ​​alternating current (When the good Tesla developed his idea of ​​alternating current 12 inch, eg) When the good Tesla developed his idea of ​​alternating current 10 When the good Tesla developed his idea of ​​alternating current; like the number 60 compared to 50.

Furthermore, they use fractions of an inch for submultiples. We of the metric system instead everything in base 10 and fractions must absolutely be converted into decimal numbers ( 5/8? but what does it mean? 0,625… ah then everything is fine 😊).

### Because there were 110V, 120V e 125V?

It all begins with Edison who empirically chooses a direct current voltage of 110V. The first use of electricity was that of lighting. Edison tries to find a material that glows in the right way, and it came out with a voltage of 110V.
When the direct voltage has passed to alternating voltage, they wanted to safeguard the compatible devices in possession of customers, ie resistors and, just, the bulbs. Therefore an effective voltage equivalent to the direct current one was considered. I write “effective voltage”, because in reality the 230V alternating current is not 230V as if it were direct current.

But it varies cyclically (50 times per second), between zero and + 325V and then return to zero and drop to -325V and return to zero.
The effect of this cyclical trend on a resistor is equal to that of a direct current at 230V. With the 220V it reached up to 311V, with 240V you get up to 339V.

Regarding the 125V, it should be remembered that it existed as a rounding of 127V which is the star-shaped value of the 220V triangle voltage.
Once the 220V three-phase was also used (which measured 127V between phase and neutral, that is 125V, used for light).

### Because 50 the 60Hz

The choice, when there was no common convention, it was the one that allowed the maximum yield of the generator, therefore it depended on the type of generator and construction characteristics of the engine
mechanic (typically steam or hydraulic machines).

At the beginning of the history of electricity, the one mentioned from the era of light bulbs, generators often had 8 poli and worked at 2000 revolutions per minute. Now, 2000 rounds / 60 are 33.33… revolutions per second. Whereas at the passage of each pole, we have a reversal (a semi cycle), with 8 poli
we have 33,3 x 8 / 2 = 133 ed 1/3 of Hz of frequency.
However, such a high frequency lends itself badly to motors.
And so a lower frequency was thought of, so that, using the same power line, motors could be powered together with electric bulbs.

In the past, the standard in Europe provided for two frequencies: 25 Hz e 50 Hz, then in 1914, i 25 Hz was removed from the VDEs.

There is no certainty, but only hypotheses “plausible”, of why’ Westinghouse had chosen 60 Hz and the German AEG instead the 50 Hz. The arc lamps that were once used where powerful lights were needed, they worked better at 60 Hz rather than a 50 Hz. Furthermore, an engine a 50 Hz requires
more copper and iron than one from 60 Hz of the same power.
But the transformers from 60 Hz have higher losses than a transformer from 50 Hz or require more expensive constructions.

After this roundup of news or curiosities I stop. I hope I have aroused a little’ of curiosity to encourage you to do your research, as the first article after a forced break of one year it seems to me more than enough

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