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I'm currently developing a DC-DC buck converter that has a rated output of 10A/60V. When the average output current is 7.5 amps, my main inductor heats up to about 40°C (room temp's about 25°C). I made the inductor myself, with a T300 red ferrite core (OD = 7.2 cm, ID = 4.9 cm, t = 1.27 cm), and a permeability factor of 10. For the wire, I'm using a 2 mm enameled copper wire. I did around 220 turns to get 600 µH. You can see the inductor in the picture below.

enter image description here

My question would be, how hot can the inductor get before it causes problems in my circuit? Does operating the inductor in 40°C safe? If not, how would you recommend me lowering the wire temperature?

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  • \$\begingroup\$ I don't have a hard number but 40C is fine. That's not even too hot to touch. Even magnets don't demagnetize there. Beyond 50-60C which is too hot to touch is when you possibly start running into problems but a lot of electrical and electronic components also run fine at those temperatures, especially things that aren't semiconductors, magnets notwithstanding. \$\endgroup\$
    – DKNguyen
    Commented Jun 11, 2022 at 18:22
  • \$\begingroup\$ Yes, it's only warm to the touch, and I decided not to test the circuit for higher output current. My main concern is about the inductor properties changing due to the temperature rise. Should I be worried about that? \$\endgroup\$
    – Kevin
    Commented Jun 11, 2022 at 18:27
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    \$\begingroup\$ I wouldn't be worried about properties changing for an inductor at least. \$\endgroup\$
    – DKNguyen
    Commented Jun 11, 2022 at 18:27
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    \$\begingroup\$ You should look for the safe operating temperature of the wire insulation. \$\endgroup\$
    – Uwe
    Commented Jun 11, 2022 at 18:27
  • \$\begingroup\$ What about the datasheet of the inductor core? Is there any information about temperature and its influence to permeability? \$\endgroup\$
    – Uwe
    Commented Jun 11, 2022 at 18:31

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