Ask Question. Asked 6 years, 1 month ago. Active 3 months ago. Viewed 19k times. Improve this question. David Z SuperCiocia, if you don't like where this is going, feel free to change it back, but I think this will help stave off the objections which I would have agreed with about this not being a physics question.
Closed questions and closing questions are unrelated. A closed question has a "yes or no" answer. Another reason is transformer-cores Lower frequency, would require more iron and thus larger transformers. With a higher frequencies, everything electrical would make a more audible hum 50Hz is at the limit of the human ear. Show 17 more comments. Active Oldest Votes. Why is mains voltage V and not 10V or V? Improve this answer. Schwern Schwern 4, 2 2 gold badges 16 16 silver badges 25 25 bronze badges.
The point about Hz destroying a spinning generator is really nice. If you increase the number of poles wired in parallel as you don't want more phases by n , the speed should drop by a factor of n.
These generators have larger diameters to accommodate all the poles. They are long and have a smaller diameter. The stresses limit the maximum diameter of these generators, it is a materials problem. It has to do with the medium driving the turbine, steam is concentrated energy, hydro gets its energy from a large volume. When you say "why can't they just", remember these standards were being developed in the s when there was no "just" for anything to do with electricity.
Show 4 more comments. Frequency Why a standard? In summary, because of the time invariance and linearity of electromagnetism, it is considerably more practical to choose a single frequency and stick to it Light flicker In a historical note by E.
Further reading Detailed document by E. I consider this answer a work in progress and will add more as I learn more. DanielSank DanielSank As I said, it's a work in progress. Add a comment. The voltage issue is much simpler. Nicolas Nicolas 1, 7 7 silver badges 12 12 bronze badges.
You say power dissipation goes as current squared, but it also goes as voltage squared. There is probably a simply explanation if one considers the circuit theory properly, but I've never seen this explained in a convincing way. Now if your wires have 0.
Which means you lose 4 times as much with V, and your wires heat 4 times as much. Useful power to the load is the product of the useful voltage and in-phase current. Waste power is proportional to the product of total current and its associated in-phase unwanted but unavoidable voltage drop. In general, current is chosen to given the desired amount of useful power, and the unwanted voltage drop is proportional to the current, thus making waste proportional to current squared. Something to do with the numbers of windings?
More cycles per second is more energy. Keeping cycles constant, OTOH, we see that energy converted scales with size. Combining the two, we see that at lower frequencies we need to increase the size to keep the power constant.
A short, therefore infinite magnetic flux. Now think of what happens as you lower the frequency, you'll have to approach this limit all else being equal. Therefore the magnetic flux becomes larger in the core and so to avoid saturating the core you have to make it larger. Internally they create a high frequency, allowing them to transform the voltage with much lighter transformers. For example, companies in the U.
For most standard motors, the RPM is proportional to the frequency, which means there is a speed increase when you use 60Hz versus 50Hz. There are little to no differences, however, between factors like bearings difference, rated torque difference, and slip difference.
Think you may need to switch between one Hertz type to the other? Check out this frequency converter to see how you can do that. As you can see, there are many differences when it comes to 50Hz vs. By knowing these options and how they work, you can make the most informed power decisions going forward.
Did you find the content in this article useful? Explore the rest of our website for more insights! Information contained on this page is provided by an independent third-party content provider. The lower the frequency, the lower will be the iron losses and eddy current losses. Lower the frequency, speed of induction motor and generator will be lower. The design of such magnetic machines is such that they are really one or the other.
It may work in some cases, but not always. To change between different power supply frequencies will certainly have an effect on efficiency, and may mean de-rating is necessary.
There is little real difference between 50 Hz and 60 Hz systems, as long as the equipment is designed appropriately for the frequency. It is more important to have a standard and stick with it. The more significant difference is that 60 Hz systems usually use V V or thereabouts for the domestic power supply, while 50 Hz systems tend to use V, V etc.
This has the impact that house wiring needs to be twice the cross section for the V system for the same power. However the optimum system is accepted as around V wire size and power required versus safety.
It is no big difference between 50 Hz and 60 Hz, nothing is bad or good basically. To obtain optimum performance, motors used for 50 Hz applications should be specifically engineered and manufactured for 50 Hz. Frequently, the delivery of 50 Hz products is such that an alternate course of action, utilizing 60 Hz products, is desirable. The general guidelines for operating 60 Hz motors on 50 Hz systems relate to the fact that the volts per cycle have to remain constant with any change in frequency.
Also, since the motor will operate at only five sixths of 60 Hz speed the output horsepower capability of 50 Hz is limited to a maximum of five sixths of nameplate H. Source: U. Machinery imported into the United States is often rated at an operating frequency of 50 Hz—unless engineered for operation at 60 Hz.. This can be problematic for electric motors. This is especially true when operating pump and fan loads. Often, the distributors and purchasers of this machinery assume that the Original Equipment Manufacturer has taken this into consideration.
This is recognized when motors are received for repair roasted out from overload. Motor speed is directly proportional to the operating frequency. Changing the operating frequency on a pump or fan increases the operating speed, and consequently increases the load on the motor.
0コメント