Why the suply frequency in INDIA is 50HZ

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  • Jun 21st, 2006

Hi, The frequency of the generated voltage basically depends on:

1). The speed of the Rotor (Field Winding) of the generator/alternator

2). No. of Poles of the  alternator.

By increasing both factors we can increase the generated frequency of the system but in increasing the frequency cost also increasees thats why both factors are limited by the other physical factors and cost. As explained:

1). The speed of the Rotor is limited by the capacity of the 'Prime Mover' which is revolving it and by the strength of the material by which Rotor is made of (otherwise it may bent at high speeds)

2). The no. of Poles are limited by the growing size of the machine.

But simulteneously we can't take very low frequency also as the AC has quite large advantages over DC system.

So, The conclusion is that the frequency band of Around 50-60 Hz is an optimized value of the frequency in both respects i.e. Cost of generation and advantage of frequency. 

If still not clear ->get in touch directely -> karan.sorout@gmail.com/  9313696291


  • Jun 25th, 2006


There is a condition that in india the electrical power generation is only by natural process such as running water from falls,hydel energy ,bio fuels etc.

But in USA the power gen is nuclear so they have 110v,60Hz.

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Akshaya vikram .K

  • Jul 2nd, 2006

The supply in India is 50HZ due to the following factors :
1. Due to cost efficiency
2.Practical difficulties in using 60HZ supply as in USA

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dayakar jogu

  • Jul 27th, 2006


    The reasons for power supply frequency in India to be 50 Hz and in US to be 60 HZ are:


                  The average annual temperature of India is greater than US


                   To generate power of that frequency it costs alot and the size of the alternator is huge and it costs an incredible amount which we cant afford


                    As frequency increases eddy current and hysteriss losses increasesand hence power loss also increases.



  • Jul 14th, 2007

The Formula of that Questions is depend on N=120F/P

N=Speed of the Rotor
P=No of Poles
F=frequency range
120=constant value


Anand modakwar

  • Aug 13th, 2007

because British people established first power plant in India that is of 50 Hz and India then follows the same practice

abhishek katkar,latur

  • Sep 3rd, 2007

    the first power plant was established by British in india.they ruled us about 150yrs
    therefore we r using their principles. also i think the value 50Hz is the optimum          value which can be achieved in india on the basis of sources available in india
    there r so many factors considered selecting value of frequency which u know
    very well

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  • Jun 28th, 2009

In US the frequency is 60hz and 110v supply. In India it is about 240v, 50hz supply. For a particular load say 100kw, the current will be 0.416A, but in US the same load will consume about 0.9A. Here the thing is, the heat produced in the cable bcoz of the flow of current will be large in US compared to India. Since US is a cold country they can use this level but not by India.


  • Jun 11th, 2011

This is nothing but a standardisation... u know.. in most of the countries across the world the frequency is 50Hz.....b,coz of this the manufacturer doesn't have to bother much about the consumer particular needs..all consumers will have the same needs..!! suppose now a days u go to purchase a fan u need not to mention the frequency but if it would have not been standardised then u will also have to mention the frequency..!!

in US the frequency is 60hz and 110v supply. but in India is about 240v,50hz supply. for a particular load say 100kw the current will be 0.416A. but in US the same load will consume about 0.9A. here the thing is the heat produced in the cable bcoz of the flow of current will be large in US compare to India. since US is a cold country they can use this level but not by India.

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  • Oct 23rd, 2011

in late India when British electrical engineers modifies and make use of uses the 50HZ frequency . After that we Indians manufacturing and marketing in huge amount of our devices and electrical appliances on the basis of that frequency

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You are right, its all bout standardisation. Once standardisation is fixed for Indian (50Hz) by British, so its continuing and In America its 60 Hz according to their standardisation.

But real question is "why standardization is 50-60Hz only, why not 150Hz or 10Hz?"

Its only because, too low value will create fluctuation in apparatus like Bulb starts blinking(persistence of eye is 15 Hz) and too high value will lead more hysteresis and eddy current losses in many machines.

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  • Nov 9th, 2011

Ok. In the generators the whether the speed (RPM) is constant, or if it is variable how the frequency is maintained constant and how that frequency is formed?

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  • Nov 20th, 2011

In India the supply frequency is of 50HZ.

1.For parallel operation In Power station the ratings of all alternators must be same. For this reasons the nos. of poles and prime mover power given to all alternators are same. Hence frequency is constant.
As frequency depends upon speed and nos. of poles.
where n= syn. speed
p= no. of poles.

2. According to I.S rules all electronic devices uses in India is operated on Freq. range between 50-60HZ.

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In the early years when generation of electricity just starts in India , it was on 50 Hz. More and more generators are connected through grid continuously over the years and so the 50 Hz frequency is adopted in India.

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madhu y

  • Aug 25th, 2012

The turbine which is used in generating stations runs at reasonable efficieny in 3000-3600 rpm.

If N=3000 rpm

If p=2 (generally we take 2)
if N=3600rpm
then f=60 hz

so we take 50 hz as standard frequency for the standard supply of power to the consumers.

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shivani shivhare

  • Sep 3rd, 2012

because all the equipments,machines are designed in 50hz in india ,if we change the frequency then all the equipments are not working on that frequency . we use the all the frequencies just as 60hz,65hz,70hz. it depends on the use only.

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  • Sep 8th, 2012

There is no hard and fast rule of 50Hz to be selected as supply frequency. Its just one has to standardize the frequency so that all the equipment are to be designed in this way for maximum utilization. USA is having supply frequency of 60Hz

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  • Sep 16th, 2012

I completely agree to the above answers saying the 50Hz frequency is put for a common operating frequency for all electrical equipments to work at.

Also our steam turbines which are major part of Indian electrical power generation are mechanically stable when they run max speed 3000rpm. So this is also a reason behind the standardized 50 Hz operating electrical power supply frequency.

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  • Oct 27th, 2012

Actually 1.) India depends 50hz,becaz Britishers designed as per there country standards.
2) In our market major electric/electronics all are works in funda.
3) Economy of generation,transportation's of power like cables,insulators,devices physical structure,protection relays etc.
4) India power generation depends major on thermal plants so,these boilers are effected by steam pressure.

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  • Aug 9th, 2013

bcoz of environmental conditions

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Rabindra raut

  • Nov 19th, 2013

The frequency in india is 50 hrz becuase the british designer give this standard acconding to environment condintion the avaibility of euipment and we follows that till now

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  • Dec 4th, 2013

in steam power plant the speed of turbine should be in b/w 3000-3600 for economical purpose in India we choose 3000 rpm and in US 3600rpm.So, ur freq is 50 hz

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venkatreddy tara

  • Jan 28th, 2015

Suppose If there Is no standardization in the frequency, Then It Is difficult to transmit power to the  electronic device with different frequencies...so In the past  Britishers sets the frequency according to our standards

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pawan verma

  • Mar 15th, 2015

but generally 4 pole, 1500 rpm speed of generator is optimum because when we take 2 pole then we cant take wave winding of coil in generator so we take 4 pole which is suitable for both lap & wave.

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  • Mar 19th, 2015

why the same load will produce different current values?

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krushna ch nayak

  • Sep 4th, 2015

Frequency is directly dependent upon the pole & speed of the turbine
we know -N=120f/p
& F=NP/120

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  • Oct 31st, 2016

Frequency is constant in a grid is because
1) All Equipment are designed for 50hz. Frequency
2) We genrate 50hz. 230 volts so in India all generation plant are 50hz.
3) All grid are inter-conected so if frequancy is not constant then equpments are damage due to change in freq.
4) Our transmition lines are old and in a starting of generation of power is 50hz
5) This frequancy depends on number of poles and speed of rotor if we increase no. of poles than size of machine increases if we increase of speed then cost of machine parts increases

so in view of above listed reasons frequency of grid is constant in India

If frequency varies than effect of other generator is we know that many companies genrator syncronise with grid without cut power supply run the plant and syncronising matching voltage, frequancy, phase angle if frequancy varied than syncroniging condition not full fill and reason of this genrator react as a motor and damage of genrator so due to this reason grid freqancy constant

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deepak kapoor

  • Dec 9th, 2016

True formula is Ns =120F/P

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