Heat dispation of large current solid state relays 2

[BillyDelta]

I have 400 VAC 30 to 80 Amp aplication (the solid state is rated 600 VAC 125 Amp) Which I plan to use with 3 (phase) resistance furnaces (5 heat treatment furnaces).

Since I have refrigerated coolant (24°C)already going to the furnaces, I would like to use fluid cooled heat sinks.

The supplier recommends 0.14 K/W (+ fan) heat sink.

I found "Fisher Elektronik" fluid coolers they show the heat disipation on a graf on one side Q[W] on the other Vw[l/h], based on a 26°c inlet.

with values which vary from 1200 to 2200 Q[W]

How do I calculate or convert these values to see if the dispation is sufficent.

How is it possible that fan cooled heat sinks seem to disipate more heat than fluid cooled ones?

If you know a better fluid heat sink supplier, or a little conversion program pls inform me.

Best regards

Billy

 

[ScottyUK]

Aavid Thermalloy are a good place to start:

http://www.aavidthermalloy.com/products/liquid/index.shtml

You should be able to get a thermal resistance far below 0.14W/K with a liquid cooled heatsink.

You should be able to calculate your losses in the SSR for your operating condition, or the SSR datsheet will give worst-case losses for FLC. The alternative method is to work back from the maximum acceptable die temperature for the silicon assuming you have data for the thermal resistance of the SSR package and determine the maximum acceptable thermal resistance for the heatsink. Can you post a link to the SSR data sheet? That would help a lot.


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Sometimes I only open my mouth to swap feet...

 

[itsmoked]

Specifically:

http://www.aavidthermalloy.com/products/liquid/standard.shtml

or

http://www.aavidthermalloy.com/products/liquid/contact.shtml

Or Wakefield.

http://www.wakefield.com/PDF/Cold_Plate_Spec_Sheet.pdf

Both these sites will have a technical section for calculations too.

Keith Cress
Flamin Systems, Inc.-

http://www.flaminsystems.com

 

[BillyDelta]

On the company web site there is nothing, I e-mailed the tech. support, i'll post it when I get an answer.

Thanks for your support.

Billy

 

[itsmoked]

Ya just have to persistent..

http://www.aavidthermalloy.com/technical/papers/pdfs/select.pdf

or

http://www.wakefield.com/pdf/thermal_tutorial.pdf

Keith Cress
Flamin Systems, Inc.-

http://www.flaminsystems.com

 

[ttocsmij]

You've found the Fischer Electronik data sheets (

http://www.fischerelektronik.de/fischer/uploadfischerfcool/Fischer/A.9.E.pdf)

and the unit differences [eg, degrees K per watt (K/W) or liters per hour (l/h)] are just conversion issues. Check out Josh Madison's Convert 4.10 (

http://www.joshmadison.com/software)

for a pretty good converter. To be honest, if your product is primarily for the American hemisphere, the Aavid product would probably be a better choice. But if your product is primarily for the European market, then the Fischer product should be considered carefully. In either case, if the listed products are insufficient for your needs (ie, cannot remove the heat fast enough based on your calculations), I am sure that either firm would be more than happy to work with you on a modification to their standard product that will.