Hi all,
I only need to be sure about right size of this heat sink:V4511....
Project: High power supply 0-30V DC and up to 20A. See schematic included.
I found some maths :
Choice: T0 220 package
Θjc :jonction > case 1°C/W
ΘjA :jonction > ambiant ( No Heat sink ) 35°C/W
With 4 LM338 and 400 Watts, 100W > LM338
100= ( Tj - Ta )* Rth Tj: junction temperature
Ta: ambiant temperature
100 = ( 125 - 55 )* Rth
Rth = 1,42 °C/W
In fact , I found calculations with Rth jc ( junction to case )
Rth ja ( junction to ambiant )
Rth ca ( case to ambiant )
Rth ch ( case to heatsink )
Where to find Rth ca and Rth ch,in LM338 datasheet?
Also V4511 has data in K/W, Kelvin degree or ? o° K -273°C so???
Is it a good or bad choice for this power supply, and why???
Thanks a lot.
jm
http://www.eleccircuit.com/high-power-supply-regulater-0-30v-20a-by-lm338/
I only need to be sure about right size of this heat sink:V4511....
Project: High power supply 0-30V DC and up to 20A. See schematic included.
I found some maths :
Choice: T0 220 package
Θjc :jonction > case 1°C/W
ΘjA :jonction > ambiant ( No Heat sink ) 35°C/W
With 4 LM338 and 400 Watts, 100W > LM338
100= ( Tj - Ta )* Rth Tj: junction temperature
Ta: ambiant temperature
100 = ( 125 - 55 )* Rth
Rth = 1,42 °C/W
In fact , I found calculations with Rth jc ( junction to case )
Rth ja ( junction to ambiant )
Rth ca ( case to ambiant )
Rth ch ( case to heatsink )
Where to find Rth ca and Rth ch,in LM338 datasheet?
Also V4511 has data in K/W, Kelvin degree or ? o° K -273°C so???
Is it a good or bad choice for this power supply, and why???
Thanks a lot.
jm
http://www.eleccircuit.com/high-power-supply-regulater-0-30v-20a-by-lm338/
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