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Why we use exactly 50 Hz and 60 Hz, instead of 100 Hz or even 400 Hz

1-is it for light

2-is it for the speed of ac motors

Can I use a machine that work in 50 Hz ac network, in 60 Hz network

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This picture shows a motor of 15 KW 220-230V /50HZ this motor run a water pumpe My question is: can this motor work in 60 Hz network without damage Will it's speed increase

m salim
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  • I know 50Hz is useful for clocks run by the mains frequency. – Bradman175 May 26 '16 at 10:21
  • A part of the response is covered in http://electronics.stackexchange.com/questions/115200/why-does-the-usa-use-110v-and-uk-use-230-240v/236470#236470. Regarding whether you can use the machine, it depends. You have to tell us exactly what machine it is. – dim May 26 '16 at 10:26
  • Well I dont believe that such big motor runs on 3x220V, perhaps 3x400V, look the nameplate you will see averything is described. IMO, no problem at all to use it on 60Hz, the speed will be 20% faster. – Marko Buršič May 26 '16 at 14:12

3 Answers3

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Transformers - these would prefer both a lower frequency and a higher frequency. A lower frequency would mean eddy current losses in the laminates reduces. A higher frequency means fewer primary turns because primary inductive reactance increases and this means less copper loss under load.

So is 50 Hz the Goldilocks value for power transformers - no because other parts of the world use 60 Hz. Is 100 Hz too high - probably on the verge of being too high for power transformer cost effectiveness.

What about induced voltages from those overhead cables. The higher the frequency the greater the voltage induced in other objects and this in turn can cause problems. Faraday basically said this: -

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So for a given current in an overhead conductor (for instance) the rate of change of flux would increase proportional to frequency and induced emf would increase in objects placed close by. Would this cause a problem at (say) 100 Hz. Maybe it would - maybe AC motors would suffer with increased losses in ironwork due to induced emfs causing eddy current flow. I guess this is pretty much related to laminate eddy currents in transformers.

Skin effect in conductors carrying high current is also of significant importance. Wiki shows a picture of overhead cable like this: -

enter image description here

Note the bundles of conductors formed into a triangle. Wiki say: -

The 3-wire bundles in this power transmission installation act as a single conductor. A single wire using the same amount of metal per kilometer would have higher losses due to the skin effect.

Increasing the frequency increases the skin effect and this will reduce the power delivery capability of feed cables because AC current tends to want to flow in the outer part of a conductor: -

enter image description here

How much will higher frequencies affect copper losses: -

enter image description here

So, if frequency doubles the AC resistance increases by \$\sqrt2\$.

Andy aka
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The reasons to use 50 or 60Hz are mainly historical. Lower frequencies are problematic for lighting because of flicker.

Regarding your question, as others said, we have to know more about the specifics of your machine to answer. Some devices, for example electromechanical clocks, cannot work in frequencies different from those they were designed for.

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

Claudio Avi Chami
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50/60 Hz is used to allow transfer over long distances. If you go to say 400 Hz, the power line inductance will become significant and you will need vast amount of compensation along a long transmission line. Transformer size would be smaller, but the overall cost would be much higher. For very long distances, you need to go even lower in frequency, i.e. HVDC, for sea cables (~500+ km) or very long overhead lines (10,000+ km)

winny
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