Vertically yes . In fact I'm looking for a heatsink model that develops at the top.

 

Hello guys,

i need your help if possible. I created a dual voltage power supply using LM317 and a LM337 both in TO220. The problem is that when empty everything is ok but when I connect the load they heat up within two minutes also with heatsinks. I give a brief description of the circuit. The transformer generates me 17-0-17 Volt AC (150mA + 150mA I know it's small but it's just for testing) which rectified and stabilized become +22.8 0 -22.8 Volt DC. This is the input voltage to the voltage regulators. There are 6 of which three are negative and three positive where each one generates a different output voltage which is:
+/- 12 Volt
+/- 5 Volts
+/- 1.5 Volt

The transformer is wrong type, too high voltage. If you must go with such, then use at least switching type reg. to drop to closer to 12V so you don't need such huge drop done in LDO.
Else just use bigger heat sinks and live with the heat and electricity bill.

 

Actually I use a 12v ac and temp is lowered but need more heatsink or a fan. To do simply for testing I had tried the fan "undervolted" and the temp was stabilized at about 45°C , but supply stage must be redrawn.

 

Those are the smallest heatsinks I have ever seen. Very little cooling.

 

Actually I use a 12v ac and temp is lowered but need more heatsink or a fan. To do simply for testing I had tried the fan "undervolted" and the temp was stabilized at about 45°C , but supply stage must be redrawn.

If you have space for bigger cooling fins then why not use it ?

 

Because i never found a good substitution to fit.

 

Because i never found a good substitution to fit.

How much area on the board, and how much vertical distance above the board do you have?

 

Because i never found a good substitution to fit.

Just pick what you need, there is tons of different versions...
https://www.google.com/search?q=to2...U_gf0HHSaXAAsQ_AUoAXoECAEQAw&biw=1333&bih=883

 

Hello,

Looking at the space, this heatsink will likely do a better job:
https://nl.farnell.com/ohmite/fa-t220-38e/heatsink-to-220-black/dp/2097690

Bertus

 

Hi, already seen but does'nt fit. Thanks anyway.

 

From a rough thumb-measure of the pic of the heatsinks, it looks like you have put the them upside down. Get some taller ones (tall as you can fit) with the same footprint. Assuming they cannot short to any other component (or ground, etc.), you can use thermal compound with no insulating washer. Then use a small fan to cool them.