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20th February 2020, 19:32 #1
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would an engineer use this equation?
i found this equation on the internet 2 × √ ( i/n × π × a) for calculating the gauge of both the primary wire and secondary wire of a flyback converter. i is effective current, and n is number of turns, a is current density, and the article said pick 4 amps per millimeter squared to 8 amps per millimeter squared. would an engineer actually use this equation?

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21st February 2020, 00:04 #2
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Re: would an engineer use this equation?
A real engineer skilled in the art would consider this
a very rough guide and from there, move on to more
analysis and characterization. The Ridley power supply
group on F*c*book currently has a lot of discussion
about such things  measuring and modeling and
theory and some experience based anecdotes.
Your current density tolerable depends a lot on the
xfmr construction, and application environment
(temperature called out, and the thermal path to it).

21st February 2020, 01:24 #3
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Re: would an engineer use this equation?
so that means yes he would?

21st February 2020, 02:19 #4
Re: would an engineer use this equation?
ONLY as a preliminary estimate, yes.
The temperature rise will have to be measured with worst case conditions.My batteries are recharged by "Helpful Post" ratings.
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21st February 2020, 03:46 #5
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Re: would an engineer use this equation?
so an engineer would use this equation. then he would have to measure temperature rise. i think i understand this.

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21st February 2020, 21:46 #6
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Re: would an engineer use this equation?
R = rho. L / Area is what an engineer would use, watts dissipated = R . i^2 ( for rms current in the wire )
then there is an added heating effect from a close wound coil of wire, i.e. internal hot spotting
kind regards  an engineer.

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21st February 2020, 22:02 #7
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Re: would an engineer use this equation?
so an engineer would use this equation R = rho. L / Area to calculate temperature rise?

22nd February 2020, 04:55 #8
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Re: would an engineer use this equation?
temp rise is a function of the watts dissipated in the Tx and the surface area and shape of the Tx and any cooling air flow  there is no simple formula for this only experience ...

22nd February 2020, 17:12 #9
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Re: would an engineer use this equation?
what is the Tx?

22nd February 2020, 22:41 #10
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Re: would an engineer use this equation?
Here, it is "transformer". But in other discussions it
could as well be transistor or transmitter, depending
on context.

22nd February 2020, 23:40 #11
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Re: would an engineer use this equation?
i am thinking i will use the equation 4 amps per millimeter squared equals amps through copper wire over cross section of copper wire to calculate gauge. i will select the input current and solve for crosssection of copper wire, and then use a wire gauge table to convert from millimeter squared to gauge. if i use this equation, will the flyback converter still work?

23rd February 2020, 00:06 #12
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Re: would an engineer use this equation?
if i use this equation, will the flyback converter still work?
Part of the world that you live in, You are the part that you're giving ( Renaissance )

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23rd February 2020, 02:20 #13
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Re: would an engineer use this equation?
i am trying to learn how to design and build a flyback converter. should i start with the equation i used in post 11 and the other equations i found on the internet? i just trying to learn how to do this.

23rd February 2020, 03:30 #14
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Re: would an engineer use this equation?
Hi,
i am trying to learn how to design and build a flyback converter. should i start with the equation i used in post 11 and the other equations i found on the internet? i just trying to learn how to do this.
There are a lot of online courses, design notes, tutorials on how to design flyback converters.
Look for some reliable ones, from big semiconductor manufacturers or universities.
They are good and free.
They tell you all you need to know.
There also are free simulators.
KlausPlease don´t contact me via PM, because there is no time to respond to them. No friend requests. Thank you.

24th February 2020, 02:30 #15
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Re: would an engineer use this equation?
Links to tables of wire gauges showing specs and safe amperecarrying capacity. There is a difference as to whether the wire is in open air, or bundled on an inductor.
http://amasci.com/tesla/wire1.html
http://www.powerstream.com/Wire_Size.htm
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