What's More Efficient?

Traditional

http://en.wikipedia.org/wiki/Utility_frequency

From Google answers:
Note: Static hysteresis loss is proportional to frequency. An equation
called Steinmetz equation can be employed to arrive at the fact that
60 Hz supply causes more dissipation of heat and energy than 50 Hz
systems. Hence it is not preferred by many countries. The losses being
proportional to the square of the frequency, is hence very high for 60
Hz systems.

You are going into a complex logic .

50Hz and 60Hz were decided long before that. Hence traditional.

If you put this, there will be people up in arms proving 60Hz better than 50Hz (more RPM means less mass weight volums - speed ratio) and ....

And then why not 40Hz or 30Hz or zero Hz.

There may be an optimal freequency, but no one as far as I know has bothered to find it (or has?)

And end of the day, even one finds, it will be a hell of a problem to change all systems to that frequency (even more than imperial to metric)

I'm sure you have a point there, somewhere, but it escapes me.

Of course there are advantages and disadvantages in making any engineering decision. Recognizing these advantages and disadvantages are the fundamental responsibility of a competent engineer. The overriding concern in this matter is to design for the local power distribution frequency. But it's not a big difference between frequencies and therefore many designs can be made to not care. There is no universal advantage to either standard, if there was then some effort to migrate from the inferior frequency would exist. A few of the differences these two frequencies might change I believe would be the following:

• Motor and transformer eddy current losses
• Motor and generator bearing wear rate
• Power supply capacitor values
• Inductive heating efficiency
• Transmission line sub-station distances
• Motor running speed
• Clock timing references

This is not intended as an exhaustive list. Nor will I choose which frequency works best with each concern. This would require more knowledge not presented here.

But to answer your question, there is no significant advantage to either power distribution frequency.

frankcorners; i feel it was 50 HZ because of the metric system used perry

50 Hz was chosen in the UK long before any move to change to the metric system.

50 Hz has lower losses

60 Hz uses less material in motors and transformers

400 Hz is used in aircraft and has much lighter motors and transformers

Also mind skin effect. The higher the frequency, the higher the current density is on the outside of the conductor and the lower it is in the center (even reaching zero if conditions are right). Thus transport efficiency is higher with 50Hz technology than with 60 Hz because of a more evenly distributed current density over the cross section of the conductor.

I've been told that in some HF applications, conductors are watercooled (!!!) with water canals in the center, thanks to skin effect.

Some 50Hz applications are water cooled in the same way but in their case has nothing to do with skin effect. I worked on an electro-plating supply with 50,000A output, the transformer windings were hollow conductors with water cooling.

Many of the old electric rail systems used 25 and 30 cycle power. There were large dynamos set up in the local generating stations to produce it.

This decision is so old that is in the history book.

50 Hz is better than 60Hz for human use since it has low loss and get more return on the investment. The loss is due to heat and eddy current.

The application base it will change if you need your motor to work harder you need to have high Hz like plan motor run on 400Hz and they are considering for higher number still to give a smooth lift up

Hey thanks to all !! all had informative and valuable suggestions !! Thanks once again !! i conclude that 50 hz is efficient WRT to the info all have put and i ve learnt abt the pros and cons

O crs nt. . sxtyh is mr efct (ev 4kH ie usd in arcfts). y shd othr hzs b thr?

(I dislike cryptic text messages in forums - may be prsonal, but one can always type in a few vowels can't they rather than murdering the language? but then I am old fashioned, may be now vowels are no more necessary so sht may be anything

http://wiki.answers.com/Q/What_advantages_60hz_over_50hz

http://www.aerospaceweb.org/question/electronics/q0219.shtml

http://www.physicsforums.com/archive/index.php/t-53692.html

I have no idea why the European nations choose 50Hz, as it is less efficient to produce and transmit over wire than 60Hz. The best frequency for power transmission is probably moderately higher than 60Hz.

Look at the explanation of Jerry H in the end. Looks authentic and believable.

This has been largely answered by others, but to reiterate:

Lower frequencies have lower transmission losses so 50 Hz is more efficient to distribute the 60Hz, but higher frequencies are usually more efficient for the users allowing smaller lighter transformers etc. (Generator rpm is also a factor hence early systems using 16Hz or 25Hz. 16.7Hz is still widely used for railway electrification in Germany, central Europe and Scandinavia)

This is exemplified by aircraft systems running at 400Hz where light weight electronics are essential but transmission losses are insignificant. Helicopters and fighters often use 1000Hz supplies for further weight reduction.

I would think, in the U.S., at least, there is some connection to AC clocks which were/are synchronized to the 60Hz.

I think for the most part, this is a moot point anyway. When does anyone get the opportunity to "choose" a frequency to operate at now?

You get what you get from your available sources. If you are generating your own power on site, I would chose generating and operating equipment that I can get readily serviced or replaced by people as close to me as possible. So for instance if I were setting up a new island nation off the coast of California, I would choose 60Hz because where am I going to get parts that can accept 50Hz if I have to replace anything? Vice versa if I were setting up a new island nation off the coast of India. Where would I get parts and service for 60Hz equipment in a hurry?

This is essentially a rhetorical discussion, there is no instance I can think of where the information would be useful.