Hello Everyone, today we are going to discuss:
Why in India we use 50 Hz for Electrical power
while in US, they are using 60 Hz, but we
use 50 Hz.
Now one would answer normally because British was using 50 Hz
that's why we also used same standard that is 50 Hz.
Now question comes, why British was using 50 Hz while in US, it was 60 Hz.
That's a real question.
To understand this, I would like to go to
the little deeper roots of electricity originating point.
Okay! so that we will understand not only
this concept, we'll understand lot many concepts
very clearly.
So, let us try to dive into those details.
If you go to the era of before Christ (B.C.),
4500 years BC,
they were using oil lamps for the artificial light.
Okay!
So after 1500 years, they've got candles.
Candles were invented to get the artificial
light.
Now in 18th Century, strictly speaking 1792,
they got first gas light.
So by using gas, by burning gas, they've got
light in this 1792.
So till this, there is no electricity.
Okay! practically there is no electricity
used.
Though some people were experimenting on the
electricity, but nothing has come out.
Okay! so in the 19th century, in the beginning
of 19th century, strictly 1800, an Italian
scientist has invented a battery.
At that time, they were calling voltaic Pile.
Okay! that is a dc battery by using chemical
process.
Okay! next in between 1800 and 1809, a scientist
of Switzerland has used this battery
to convert into light, that is what Carbon Arc Lamp.
So what he was doing is, he used two electrodes,
he placed two electrodes and in between these
two electrodes, he applied a very high voltage
so that the gap, air gap in between these two
electrodes has ionized and gives an Electric Arc, that gives lighting.
So that is a first Electrical energy usage, he
converted electrical energy into light energy by using Arc.
I am just going to the details very quickly.
Yes, they are very important to understand
50 Hz and 60 Hz. yeah! we are closely related.
Next, in 1832, a British Scientist, by using
a DC voltage,
he tried to convert the DC voltage to mechanical energy.
Yes, he successfully did it but there are
many losses.
The design was not so efficient.
Okay! so, till this time, electricity only
was DC, by using batteries only.
By using a chemical process, they got DC.
And that DC was used only for bulbs.
Though they got a DC motor, but it can't be
used practically anywhere.
Because that design was not so good.
Okay!
Next in 1832, a French scientist has got a
DC generator.
So, he converted mechanical energy to electrical
energy.
He produced output, electrical output.
Okay! and surprisingly he first got AC output.
Okay! but at that time, there was no application
of AC, he don't know how to use AC.
Okay! he don't know how to use alternating
current.
So, he converted that AC to DC by using a commutator.
Okay! so here, AC generator was accidentally
invented first but he don't know how to use
that AC generator so he converted that AC
to DC by using a commutator.
Okay!
Now, so this DC voltage so far, chemical energy was used to produce DC voltage, that is used
to give to the bulbs.
Now this DC generator was used to light up
the bulbs.
Alright! and of course, this was also not so
efficient design.
the design of DC generator is not so efficient,
but he said mechanical energy can be converted
into electrical energy through magnetic energy,
in the year 1832, in the same year.
In 1855, a French scientist, for the first
time he used AC power.
So till this time, before 1855, there is no
application of AC. But in 1855, a French scientist
has used, a Neurologist, he has used this
AC power source for Electrotherapy.
Okay, that is the first application of AC
power.
So moving on, in 1871, a French scientist
named Gramme, he has practically developed
the design (DC motor).
He developed DC motor which can be used, to
the practical world.
Okay! so he changed the rotor structure, he
changed the armature structure.
That armature is called as a Gramme ring armature
or Gramme ring winding structure.
Okay! so with that, he could efficiently turn
the motor by using electrical input, Okay.
In 1873, a French scientist once again,
another French scientist who is a friend of,
who is a colleague of Gramme, he transmitted
power for the first time.
Careful here!
See, till this what we were talking about?
We were talking about history, very beginning
of electricity.
Right now, we have light, fan everything.
But at that time, there was nothing.
Okay! even they don't know till 1873, they
don't know that electricity can be transmitted
for a longer distances through wires.
They don't know even that also.
So in 1873, a French scientist has got an
idea of transmitting power from one place
to another place for longer distances.
So till this time, if they want to light up
the bulb, they used to have a battery just
below that and they used to light up the bulb.
Okay and this invention also, it is very interesting.
I will give a story in the description.
You can check the description story.
Okay?
This invention of transmitting power is very
interesting story.
So for the sake of time, I'm not going into
the details.
Next in 1874, a Russian scientist has patented
Incandescent bulb.
So, so far the application of electricity
is only arc lamps and DC motors.
In 1874, he proposed/patented incandescent
bulb.
But this incandescent bulb can't last for
a longer time.
It used to blow off with in very short time,
may be with in few hours.
Okay!
Next in 1880, an American scientist, I think
all of you are aware of the name, yes, Thomas Alwa Edison,
he has given a practical incandescent
lamp which can last for 1500 hours.
Okay!
This has brought some significant changes
in the electricity.
So this invention of bulb by Edison, who is
not just an inventor, he is also a business man.
So to let the customers/consumers to use his
inventions, customers need a power source,
they need a power supply.
Consumers don't have any electricity.
So, he started building power plants in 1882
in Newyork city, he first launched a commercial
power plant so that people can use his inventions
of incandescent bulbs.
So he started transmitting power (DC power)
at, he generated at, 110 V, DC, 2 wire.
Okay! here,
why he has chosen 110 V, let's
have a look at that.
He intended to transmit/ he intended to deliver
100 V to the consumers.
But he knows to transmit power, he needs to
use, he needs to take use of wires.
These wires are having some resistance.
So, the resistance will take away/ will take
some drop.
So, he calculated that drop will be around
10%.
Okay! so, 10% of 110 V is 10 V in the transmission
line has lost.
So, he started transmitting 110 V at the power
plant.
So as more and more current is drawn by the
load, more drop across the transmission line
and less voltage here.
If there is no current, if there is no load/
0 A current, then complete 110 V will appear here.
 
If more current, then more drop.
Then if more drop, bulbs will light down.
Okay! they will not glow with a full intensity.
So, for this constraint/ with this constraint,
what he used to is: he used to build
a power plant for every 1 km or so.
For every 1 km, he used to have 1 power plant,
a special power plant, again corresponding loads.
Because this power plant can't transmit for
longer currents.
If more currents, more drop will be there.
Okay! now, here comes the point, interesting
point.
Point here is: To supply some 'x' amount of
watt/ to supply 'x' watt load, if you transmit
power at low voltages, current will be high.
If current is high; the losses, voltage drop
is high.
Because current is high, drop is high and
losses are also high.
Okay! whether it is a dc or ac, it is true.
Remember!! whether it is a dc or ac, it is
true.
Less voltages means more drop.
So at that time, there was no choice.
Because till then, no body used to see the
light.
There is no light, there is no electricity.
Electricity means, that's a wonder.
Okay! so yes, there was no choice.
Edison used to transmit power. Though it's
loss, yeah, people used to pay for it.
Let them pay.
Okay! during this time, they used steam engines
to drive these generators (DC generators).
Okay! but some inventors are not happy with
this power plant for every 1 km, because of
high losses.
So, Edison has revised his transmission system
to 3-wire transmission system, a DC 3-wire
transmission system by using 110 V and another
110 V, total 220 V he used to transmit using
3-wire DC system which has reduced losses
to a considerable amount.
Drop, these voltage dropped to a considerable
amount but still, he used to have a power
plants at regular intervals.
Because this can't reduce losses to a much
extent.
So, here the conclusion is: Till 1883, Okay! only DC power supply was there, only DC source was there.
There is no other alternative for this.
Okay! so people had to accept the same, though they were having more losses in the system. Okay!
So Edison was ruling that time, he used
to send his power, he was so happy.
Because all the customers are seeing his electricity or using these/ his inventions/incandescent bulbs.
Next in 1884, England scientist, two scientists,
they invented concept called a Transformer,
to change the voltage levels.
Because they understood dc power system has
no future.
Because if you transmit power at lower voltages,
it will have more losses.
To increase the voltage levels, so they designed
a transformer.
But these transformers will work only with
ac, not with dc.
So they used ac power supply. Using a transformer,
they built a first AC transmission for the demonstration
in Italy.
Okay! and they used 130 Hz frequency here.
Careful! now we are coming to the track, that
is the frequency term, 130 Hz frequency, 1-phase
power supply.
Okay! they used/they increased the voltage
level to 2000 volts, that is 2 kV.
Now the question is: Why they have chosen
130 Hz.
The reason is very simple.
Because at that time, they are having only
bulbs.
Okay! so electricity was used only for lighting
up the bulb and to turn the DC motor.
Okay! but as it is AC system, DC motor cannot
be driven with the ac system.
So this ac power is only to supply bulbs,
whether it is arc lamp or incandescent lamp.
There was no A.C. (Air conditioner) at that
time, there was no cooling fans.
Okay! there was no TV, there is nothing.
Okay! so bulbs, so if they are having/ if
they are supplying this bulbs with the lower frequency,
means more time period.
More time period means, what will happen?
if time period is high, then bulbs used to
give a flicker.
One could see the flicker of the bulbs.
So, to avoid this visible flicker, they have
gone for higher frequencies.
So they reduced this time period, means frequency is high.
So they come at/they just picked one frequency/
one higher frequency : 130 Hz.
Alright! at that time, you remember there
was nothing, no electricity, no fan, no bulb,
no projector, no digital board.
No, nothing. Alright!
Now, after 1884, successful transmitting of/successful
demonstration of ac transmission, they built
a commercial operative power plant in 1885,
in Italy, with same 2 kV but this time 120 Hz.
Because they were keep on experimenting with different
frequencies.
Okay! there was no standard frequency at that
time.
Till 1885, this ac power was only restricted
to use to light up the bulbs, not for dc motors.
But obviously one want a dc motor also.
Because motor is very important for industries.
Okay! but there was no motor which can run
with ac power supply at that time.
In 1885, an Italian scientist has got an idea
of ac motor, by using poly phase, by using
2-phase/3-phase like that.
He just got an idea, he has not implemented,
he just perceived an idea of it.
Okay! next, in the same year 1885, an American,
he is watching all these stuff here.
All these Italy, Italy's transmitting ac voltages
successfully for longer distances.
But in America, Edison who was transmitting
dc power supply, which is having more losses,
so he need to keep power plants at regular
intervals.
So another American, whose name is George,
George Westinghouse, he saw a good opportunity
in this AC, which was used in Italy.
So immediately what he did was, he just purchased
the rights, North American rights of that transformer
construction, he has taken the rights from
these England scientists.
Then he tried to modify those transformers
with, along with his team, that is William
Stanley and other people.
So they just modified the transformer, with
in just 3 weeks they modified the transformer.
The designed transformer here and in 1886,
George Westinghouse, in Us/in New York, he
just launched AC transmission line with 133.33 Hz, and he transmitted voltages at higher
voltage, that is 500 V.
At the consumer end, he stepped down the voltage
to 100 V which was giving less transmission
line losses and transmission line drop.
And in the end of 1886, he has successfully
launched commercial ac transmission line in
the New York city with same frequency but little
higher voltages and end user/customer side,
it is 100 V but the transmission voltage was
1000 V by using a transformer and they used
1-phase power supply.
So they were so happy to have this construction
in New York, in US.
Because they don't have to have a regular
power plants at regular intervals.
Okay! they can transmit this power for longer
distances. Because they can step up and step
down the voltage levels by using transformer,
that is possible only with ac power supply,
that is not possible with dc power supply.
But still some people used to say: Yeah, though
it is good to light up the bulbs but what
about the motors?
Motors can't work.
AC supply can't be used to turn the motor.
Though he perceived idea/ he got an idea,
but it is not into implementation yet.
Now in 1888, the famous scientist Nikola Tesla,
I think you have heard of this name, he just
got poly phase ac motor patents.
He just showed up to the world, by using poly-phase ac, one can convert ac electricity into mechanical energy.
That has now got a big boom for this George
Westinghouse.
Immediately George Westinghouse has taken
all the patent rights from Tesla.
He used Tesla in his industry to promote AC.
Because he has a power supply and application,
bulbs are of course, they are there and now
Tesla has powerful AC motor.
That's it.
Now to prove to the world, at that time, dc
was so powerful till then.
Before then dc was so powerful.
Because it is Edison's one.
Edison was so powerful.
But now, there was a fight between George
Westinghouse and Edison.
So they were promoting, these guys were promoting
AC but Edison was promoting DC obviously,
it's his own plant.
How can he demote his own plant?
Now, that was termed as WAR OF CURRENTS.
Anyways, in 1891, in Germany, by taking all
these concepts, in Germany, they launched
three phase AC transmission line in a demonstration
purpose.
Around at 175 kms they transmitted, Okay!
at 8000 V, as a transmission voltage and the
frequency chosen was 40 Hz.
See, they were keep on experimenting with
this frequency.
Which frequency to pick up?
Okay! they were just experimenting with the
frequency.
Now in 1893, George Westinghouse has got a wonderful
opportunity to light Chicago world fair.
Okay! in the same year, Swami Vivekananda
has given world's Religious speech in Chicago.
Okay! same year, same place.
They've got the opportunity in participating
in lighting up this world fair.
So for that, George Westinghouse has used
2-phase power supply, of course AC, with this
2200 V transmission and 60 Hz.
Now, why 2-phase?
Because in this world fair, obviously he need
to show the lights as well as he need to show
the poly-phase AC motors which can run with
AC power supply.
So they need multi phases, that is 2-phases.
He used 2 phases.
For lights, he has taken one phase out of
it, he has given to lights.
Now question comes, why here 60 Hz? because
at that time, Tesla has given idea of 60 Hz.
As people are choosing different numbers,
low frequencies are good for his motors.
Not high frequencies, low frequencies are
good for his motors.
Why?
Low frequencies means, low losses: eddy current
losses as well as Hysteresis losses so called
iron losses total together.
They will be less, if frequency is less but
if frequency is so less, the bulbs used to
give a flicker.
Okay! so they could have used 40, but Tesla
has suggested 60 based on a simple logic.
Because one hour has 60 minutes.
See here, 1 minute has 60 seconds, so he said:
one second, 60 cycles.
In one second, 60 cycles that is 60 Hz.
So they landed at 60 Hz generation.
So that's how they have come up at/ they landed
at this 60 Hz.
Okay! so this 60 Hz can comfortably light
up the bulbs and it can turn the motors as well.
Now, why if, in Chicago, if they are using
60 Hz, what happened in Europe countries?
After successful demonstrations of, you know
this ac power supply in Chicago world fair,
so people are very curious about this ac power
transmission.
So everybody would like to take the same.
So in European countries, they could have
chosen same 60 Hz, but this 60 number is not
fitting into their Metric system.
Because European system is something different.
European units are something different and
US units are something different.
Okay! like you can see yards, kilo meters:
we will say in British.
But in case of Europe, they will call it as
Yards.
Okay! there are many differences in units.
So, British units are/ metric units are something
different.
So what is their metric units?
Careful here!! we are coming to the point.
If you see our currency.
What is our currency?
We have of course Rupees.
We have one rupee, 2 rupee and 5 rupees.
Okay!
Do we have a 3 rupees coin?
No, we don't have a 3 rupees coin.
We have one rupee coin, 2 rupee coin and 5
rupee coin.
Okay! because 1, 2, 5 are the metric numbers.
Okay! and 10 multiples of this 1, 2 and 5
that is we have 10 rupees, 20 rupees and 50 rupees.
And similarly Yes, 100 rupees, 200 rupees
and 500 rupees.
We have right now.
Isn't it?
So 1, 2 and 5 are the metric standard numbers.
So the 60 Hz, what was used in Chicago is
not fitting into the metric standard numbers.
So they have chosen 50 Hz.
Now, you may ask: they could have chosen 100 Hz. why they have chosen 50 Hz?
Because I said, more frequency means more
losses in case of AC motor, more iron losses.
So they can not go for more frequencies.
They could have chosen 20 Hz but less frequency
will give a flicker.
So they have picked up: yes, 50 Hz.
Okay!
Now, I hope you understand whole story: Why
we got 50 Hz.
Not only this, with this whole story, you
keep this story in your mind, you will get
many more things later on.
Now like I will tell you.
See here, 2-phase AC system.
They were having 2-phase AC system in existence.
But there are some systems afterwards, afterwards
there are some systems who got 3-phase.
3-phase motors were so popular afterwards.
Now to convert this 2-phase existing AC to
3-phase, at that time itself, Scott, F Scott
has proposed a new transformer connection called Scott connection to convert the 2-phase to 3-phase.
So that this 2-phase power supply can be converted
to 3-phase and it can drive the 3-phase Induction motor.
Because after his invention of poly phase
AC motor, yes, complete 2-phase, 3-phase,
poly phase induction motors were popular.
Okay! so likewise there are many more hidden concepts.
So I strongly recommend you to have this in your mind.
So let us have a look at the conclusion: Right now in the world, we are having.
This is a world map with different frequencies.
Okay! so 50 Hz, 60 Hz is used.
And different voltage levels: 220 V and 100 V/120 V is used at different/both the frequencies.
Okay! and this is the world map.
So most of the countries are blue means they
are using 220 V, 50 Hz power supply.
Okay! and still in New York and in this region,
North America, still they are using 60 Hz.
Because they could have changed to 50 Hz but
if you want to/ if this complete area needs
to change to 50 Hz, then all the customers
in this area need to throw all their appliances
and they need to replace, they need to buy
a new appliances.
It is very difficult.
Okay! and here, one thing: In European countries,
what we discussed?
In these countries, they have gone for 50
Hz at that time.
okay! at the time of 1910 and so, but they
were still with 120 V at that time.
They haven't changed to this 220 V. They were still
with 120 V but 50 Hz.
So after second world war, almost all the
people are affected.
So all the appliances/Electrical appliances
are gone away.
So immediately after that, it was very easy
for them to change the voltage level from
120 V to 220 V and they sticked with 50 Hz.
Why 220 V?
Because higher voltages, higher distribution
voltages also leads to low transmission voltage
losses and low transmission voltage to drop
as well.
Okay! this is for distribution.
I hope all of you understand complete
story of this AC, from the origin.
Why AC has taken into consideration.
and then why 50 Hz has chosen, why 60 Hz has
chosen.
Everything is clear, I think.
I hope you like the video.
Please like the video and share the videos
with your friends.
And do subscribe to our channel for more such
kind of videos.
Thank you.
