Why is the frequency of current 50Hz in India against 60Hz in the USA What should be done to make it 60Hz in India?

Answer 1

A lot of points are factored when a utility decides to choose 50 or 60 hertz, sometimes it may even been a political rather than a technical one. We have seen various types of wars on measurements types of units used or have been an interested but an innocent invitee in format wars in electronics like 8 track v/s cassette, v2000 (an excellent system) V/s the betamax (also with some notable features) and the vhs. Now we are also extended into the video disc formats. However if we were to look closely many of us will agree that 60hz is a good choice. All inductors and motors could be smaller, and the benefits will encompass a wide array of electrical and electronic goods to which the changes will almost be transparent. But it should be noted that most critical and large capital intensive plants and machinery, including certain medical equipment, will not take too kindly to such a change, which, besides straying from the critical specs, or worse still may give up altogether, unless expensive time consuming replacement or an equally complicated and efficient cycle converter is installed before the system is connected to the mains.

As a historical note, 60Hz was originally chosen in the US to help market AC power systems to customers. The ploy was that a clock could run using a synchronous AC motor and at 60Hz, the gear mechanism would be greatly simplified. Then the job of keeping accurate time fell to the electricity company by maintaining a constant frequency. Prior to this, many different frequencies had been tried.

As regards 50 Hz in India it is descendant of the British Imperial system. Technically speaking operating 50 Hz versus 60 Hz would not make much difference but, to achieve it, either the prime movers - for example steam turbines, gas turbines and diesel engines - would need to be able to tolerate a 20% increase in speed or the alternators they drive - which produce the electricity - would need to be completely rebuilt with extra poles and windings so that they could continue to run at the same rotational speed. The costs of doing such re-engineering would be enormous and could not be justified as "economically worthwhile" from the point of view of actual necessity, quite apart from the severe problems which would be caused to assuring operational continuity of service whilst such changes were made.

Further, for any load equipment - machines, appliances, etc. - that have reactive components (capacitors/inductors), the effects of a frequency change from 50 Hz to 60 Hz on such impedances would not be trivial and would significantly alter their in-circuit behaviour. This means changes would have to be made to the sizes all such reactive components to achieve the same effects at the higher frequency. Doing that would be yet another enormous cost of conversion from 50 Hz to 60 Hz which could not be justified as economically worthwhile.