Specifying a Transformer: Why does 50Hz make such a difference?

Question - since flux is related to current - could a 60 Hz transformer be used with 50 HZ if you derate it by 20%?

Same voltage, but different frequency. Beware of the potential excessive heat generation if the transformer was designed for 60 Hz (as mentioned above in the thread).

plz i want to know when a transformer input is 480 v 60 hz is it the same out put if the input the same value 480 but 50 hz

hello friends, i m not replying for this matter here. but i have 12 years of experience in transformer repairing and manufacturing industry in india. now i have started my own consultancy & and all related work in transformers. i would like to meet all the persons/ friends from the same field. so my dear friends, plz reply me at ashish_patel111@yahoo.com immediately, if u belongs to power/distribution transformer industry. i feel from the deep of my heart that we can go ahead together for the same interest.

You see lines because you're using iron filings. They are reasonably discrete!

Impedance for an inductor is sL, so applying a 100V at 50Hz will generate more current than at 60Hz into the coil. Right? Of course we'll burn the coil once s is reduce to 0, or DC.

Yes, I'm glad fewer and fewer arms get broken trying to hand-crank start car engines. Unless you're providing huge power transformers for power distribution, nearly every other power supply is switch mode now days. These are easily designed not only for 50/60HZ but often wide range voltage input of 100V to 240V. This discussion is behind the times. Lots of fun!

Roger: While quantum theory may be a better way to explain the operation of a transformer, I suspect that practical design requires nothing more than Mr. Maxwell''s contributions, if that. There aren''t any relativistic effects to be observed (unless Dr. Bob gets rid of those bad transformers REALLY REALLY FAST (grin)), and folks were designing transformers long before quantum physics was a twinkle in the eye. That''s not to say that the quantum explanations wouldn''t be very interesting.

Physicist, I must be really obsolete! Are you telling me that people use quantum mechanics now to describe the fields in things as macro as transformers? I grew up in the continuous world of Maxwell''s equations, and I would have thought that this would still be the way to characterize an electromagnetic field in the macro world of xformers.

Leave it to the French.....they also built New Orleans.

I found this explanation completely inscrutable. The flux lines are a visual representation of the magnetic field. The actual field is continuous, not composed of discrete lines. My understanding of the overheating phenomenon is that the transformer overheats due to the lower impedance when operated at a lower frequency, which in turn results in higher currents. Therefore, to operate at a lower frequency, the winding wire size must be increased to handle the increased current flow. Another way to think of this is that the rate of change of the magnetic field creates the impedance. A lower frequency reduces the field rate of change, thereby reducing the impedance. Perhaps physics has changed since I took it, but the idea espoused in this article does not comport with anything I ever learned in physics or EE.

Yes, for 50 HZ you will need a larger iron core which increases the length of copper wire required for the windings which in turn means you have to put in more copper to reduce the resistance to keep internal heating at level that keeps it within the max core temp allowed for the Txmr design. I haven't designed a small AC power transformer for over thirty years, but I do remember that.

I worked in Mexico City in 1976 during the last phases of the great change out. Prior to the change out critical television equipment that operated at 60Hz was driven by huge dynamoters that converted the 50Hz to 60HZ for Televisa. Every ballast, every refigerator, etc etc etc was changed with the help of the government's change agency. The folks I worked with were really glad it was over. Floresent fixtures would overheat and drip hot black glop on the unwary office workers below. All in all it was a tremendous sucess at a great cost and the folks that had to have 60Hz equipment could finally pitch the dynamoters.

I have been to different parts of Mexico City and have never seen a 50Hz outlet. The 50Hz grid has probably shrunk to insignificant dimensions in these years.

When my family moved to Mexico City, Mexico, in 1965, the city was at 50 Hz, but the rest of the country was on 60 Hz. Evidently the French had the original contract to electrify the capital city, so they spec'd out 50 Hz, as is their custom. When the Mexicans decided to electrify the rest of the country, they saw the advantage of being able to share the power grid with the USA, so the rest of the country got 60 Hz service. I don't know if they ever resolved the issue, or if they continue to operate two independent systems, one for the capital, and another for the rest of the country.