Temp rise in an electrical enclosure

[garagefela]

Hi all,
I have been lucky enough to get a stainless steel electrical enclosure which I will be using to house all the electronics for a router build.

Measurements are 600 x 600 x 200 (2' x 2' x 8" for our US friends)

Will be housing all that is needed including three Gecko g201's running three 2.5 amp motors at around 65 volts and am wondering if the temp inside the enclosure will rise too much.

This enclosure is from a chemical plant and has been professionally built and has a really good seal on it. It also has a false base in it so the whole base can be built on the bench and then inserted into the enclosure. (as many may already know)

Really don't want the hassle of running a fan then having the problems of keeping the crap out and having fan vents block up.

Hopefully there is enough natural heat dissipation over such a large area and this may be enough.

I do realise I am asking "how long is a piece of string" so I suppose I am asking "do you have an airtight enclosure and does it heat up too much?"


Thanks all M

[Al_The_Man]

I can't see that being a problem with those size components.
Of course it can depend if you are in the north , how hot the ambient is?
I have just put a 2kva transformer in a stainless enclosure a bit larger than that one, so I am going to wait and see if it needs cooling by monitoring it in use.
Al.

[garagefela]

Yeah thanks for the reply Al,
I will go for the non fan route to begin with and if need be cut a hole and pop one in at a later stage.

As for high temps where I live the summers can get damn hot, funny as we live in Melbourne one of the most southern points on the mainland of Australia (Southern hemisphere of course) where Northerly winds can really get us hot.
Feb this year saw the highest temps seen since official records have been kept 150 years ago. We saw 46.4 degrees (116 F) in Melbourne and 47.9 (118 F) a few clicks up the road from me with winds up to 80 kays an hour (50 MPH).

This was extreme to say the least so I will have to see how it goes when the summer rocks around.


Cheers M

[Al_The_Man]

Where I am it swings between +40°c and -40°c
Al.

[martinw]

Dear garagefela,

If your ambient temperature can hit 50 degrees celsius, I do not think that the size of your enclosure is going to help you that much. The inside will sit at 50 Celcius when the equipment is off. A guess is that the electronics will add another twenty or thirty degrees. At that temperature, you will severely reduce the lifetime of the components on your boards. Yes , indeed.

Buy yourself a 120mm diameter fan, and a hole saw. Put the fan in the bottom of the box, and drill a similar hole in the top. Put a filter in the top to stop crap falling in. Buy a fan that has a good flow rating... no need to worry about the noise rating of the fan... after all, the noise from the fan will be swamped by your machine. Noisier fans shift more air and are less expensive, dollar for dollar.

What will a fan cost? I guess about £17 UK. Sorry, I cannot convert to your currency.

Good luck,

Best wishes,

Martin

[garagefela]

Yeah that's the problem when it is digustingly hot, everything just gets worse and worse.

I may just end up having to put a fan in and be vigilant on the cleanliness of the fabric filters. I suppose a bit of air movement, although hot air, is better than letting your gear baste in it's own juices in a no air movement environment.

Hey Al you can go and stick the 80 degree Delta T up where the sun don't shine. It does get cold here as well but that's just ridiculous. .....................although would save driving to the snow every year.


Thanks again M

[youngjim]

In Canada, snow comes to you!

</Yakof>

Jim

[ViperTX]

Well, I'm facing the same problem. I haven't calculated the heat gain, but moving 100 degree air (Fahrenheit) air over some components that could approach 120 or so degrees, you just can't cool it lower then 100 degree.

I just looked at the Gecko website and on the 540 there was a 24 degrees C rise when the Gecko was under load. The 540's have a max case temp of 85 degrees C, so assuming the other drives have similar characteristics you should be okay with most any air flow.

My problem is the enclosure I'm building is for an LCD TV and the max. operating temperature is 104 degree Fahrenheit, which is close to the daily high in this part of TX during the summer. Since the enclosure is in the shade, it may be 10 degrees cooler.

I have considered using a Peltier cooler for the summer and a heater strip for the winter to avoid condensation problems during winter time, keeping the insides warmer then the ambient air.

Paul

[Zig]

Garage fella,

enclosure is made of SS. Lucky for You.

Attach a heat sink on the outside and blow air across it.mount Your major heat sources on an aluminium plate and attach it to the heat sink through the wall of the enclosure.

Yeah SS is not as good a conductor of heat but its better than a poke in the eye with a sharp stick.
This way you keep enclosure sealed, get rid of heat and it still looks good.

[Al_The_Man]

Like Zig mentions, What I have done in the past is buy some aluminum extrusion, preferably finned heat sink profile that extends the length of the top of cabinet, the heat sink sits on top.
Drill two circular openings in the cabinet top under where the end of H.S. will be and then over one of the inside holes place a small fan, this blows across the heat sink and re-enters the cabinet the other end, this creates a sealed heat exchanger that works good.
The ends of the heat sink are blanked off of course.
Al.

[rokag3]

stainless steel is a very bad heath conductor the use of such enclosure for chiical plants can be justify by corosion concern .
If the temperature is good for human it's good for electronic ! so make yourself comfortable use air condition in your workshop and you may solve the problem sometime trivial solutions...
Lucien