AVS Forum banner
Status
Not open for further replies.
1 - 11 of 11 Posts

·
Registered
Joined
·
2,041 Posts
Discussion Starter · #1 ·
Hi,

I have a NEC GP-3000 and as usual the CF-Drive heat sink gets very hot and so do the transistors mounted on it.

The transistors are mounted to the heat sink with a grey tube as an insulation material surrounding the transistors.

I wonder if it could help the transistors stay cooler if I would change from these grey tubes to someting better.

Maybe Mica is better or can anyone tell me what is best there.

As the CF-Drive only works with +-35V the insulation does not have to be of a high voltage type.

Does anyone know how good/bad these grey tubes are, and if mica might be better an if yes how much?

Best Regards

Roland
 

·
Registered
Joined
·
264 Posts
I guessing that it is kinda thick so it has a lot of loss.

there is some better stuff out there but if the heat sink is overheated that is a bigger problem.


Can you touch the heat sink with out burning your self ?

if you can I guess that is less then 60c


Can you add a fan or add a bigger heat sink??

also the voltage might be higher then 35V due to the inductive kick of the yoke.



Look at the Thermal Resistance of the stuff you might want to try. Also some of the good stuff is NOT a electrical insulator!!
 

·
Registered
Joined
·
784 Posts
It's hard to beat mica and grease. Nobody uses this combo anymore in producton because it is very messy and time consuming.
 

·
Registered
Joined
·
2,041 Posts
Discussion Starter · #4 ·
If it is hard to beat mica and grease, how can it be beaten?

I would like to use best I can get to get the transistors as cool as possible without increasing the already too high noise.

If nothing can beat I will use mica+grease

Best Regards

Roland
 

·
Registered
Joined
·
784 Posts
Roland,

So sorry, "It's hard to beat mica and grease" is a figure of speech, another way of saying "You can not beat mica and grease"


So I would go ahead and use mica and grease.
 

·
Registered
Joined
·
2,483 Posts
Ceramic is not better than Mica for heatsinks. The point of the Heatsink compound on the mica washer on heatsinks to exclude air from underneath the component. Ceramics are hard and thus can't do that. The reason sil pads (the rubber ones) are used is that they they are deformable and the material moulds to the peaks and troughs of the component. Thus they have to be relatively thick so there is enough material to take up any air space underneath. Thickness=heat transmission loss. mica and heatsink compound squashes flatter thus is better.


Graham
 

·
Registered
Joined
·
2,041 Posts
Discussion Starter · #9 ·
What about those materials that are some kind of foil and get some kind of liquid when heated above a defined temperature? Are they better than thermal grease or are they just easier to handle?

Roland

P.S.:

Diamond clearly outperforms mica but who could pay for that :)
 

·
Registered
Joined
·
2,041 Posts
Discussion Starter · #11 ·
Is that Arctic Silver insulating?
 
1 - 11 of 11 Posts
Status
Not open for further replies.
Top