AWG gauge choice and assistance!!

Thread Starter

gusmas

Joined Sep 27, 2008
239
Hi

I need to wind a inductor which will experience the following:

It will be used in a buck-boost converter.

PWM Freq: 20kHz
Max Load Current: 20A

Now using the following link: http://www.powerstream.com/Wire_Size.ht,to get the wire thickness. However the wire that can handle 20kHz (AWG 19) is only able to handle 1.8A?

Am I missing something here? I hope I am.....

Thanks
 

PackratKing

Joined Jul 13, 2008
847
The link provided, indicated a URL fault, but gave a route to the "ampacity" table.

You need something to handle 20 amps, this will be at least # 12 awg.

Re; A standard household AC Outlet, provides 15 amps, and is wired with a minimum 14 awg. Please refer to National Electrical Codes...

Frequency will speak for itself, as a function of the core material you wind your project on... and the number of turns to do the deed. Those are your major considerations, and more math than is called for here...:D
 
Last edited:

Thread Starter

gusmas

Joined Sep 27, 2008
239
The link provided, indicated a URL fault, but gave a route to the "ampacity" table.

You need something to handle 20 amps, this will be at least # 12 awg.

Re; A standard household AC Outlet, provides 15 amps, and is wired with a minimum 14 awg. Please refer to National Electrical Codes...

Frequency will speak for itself, as a function of the core material you wind your project on... and the number of turns to do the deed. Those are your major considerations, and more math than is called for here...:D
whoops:

http://www.powerstream.com/Wire_Size.htm

if I may ask how did you get I must use at least a #12 awg? Was that a estimation from the "Re; A standard household AC Outlet, provides 15 amps, and is wired with a minimum 14 awg." statement?
 

Evil Lurker

Joined Aug 25, 2011
116
The inductor would have to be huge to support that frequency (along with the wire gauge) and so would the caps to handle the ripple current. You need to increase your frequency to 100khz+ IMO.
 

PackratKing

Joined Jul 13, 2008
847
whoops:

http://www.powerstream.com/Wire_Size.htm

if I may ask how did you get I must use at least a #12 awg? Was that a estimation from the "Re; A standard household AC Outlet, provides 15 amps, and is wired with a minimum 14 awg." statement?
I am a 40+ year household DIY, and have done beau-coup wiring, and even though not "licensed" I work under the purview of a licenced electrician, and subject to the same NEC and local codes, just as he is...

regarding electricity - amps are amps, whatever house they live in... whatever any given component tells it what to perform... it takes #12 awg or [sch]metric equivalent , to handle 20 amps current. Some will tell you that #14 is ok, here's the difference... I tend to lean toward overkill with things Electric / electronic.
 
Last edited:

BobTPH

Joined Jun 5, 2013
8,765
no, designed from what info i could find on internet.
I suggest you do some simulation then, or analysis to determine a little more carefully what inductor you need. A 20uH and 500uH will perform very differently.

What are the input and output voltage and current requirements?

Bob
 

Thread Starter

gusmas

Joined Sep 27, 2008
239
I have simulated my design for both inductor values and it worked as intended (i think its luck :p). Maybe my mistake was saying between 20u and 500u (inexperience). Lets say either of those values, i need a inductor for.
 

Thread Starter

gusmas

Joined Sep 27, 2008
239
Can you really take ~25V of overshoot on your 50V rail? That's 50% overshoot, and I see it on both simulations.
That is without soft startup. I am going to use a micro to control the pwm duty cycle, so will start at close as possible to 0% and slowly ramp it up.
 
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