Model Boat Mayhem
Mess Deck: General Section => Model Boating => Topic started by: chingdevil on December 28, 2007, 09:22:24 pm
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Tech question:-
I want to make a couple of cooling coils for 540 motors. What is the best material, copper or aluminium tubing? Also does the tubing have to go around the motor completely or can it be fitted like saddle bags covering the majority of the motor? One of the motors is quite close to the bottom of the boat and I am not sure I could get it all the way around.
Your thoughts are very much appreciated
Brian
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Ching, you can get them ready-made in aluminium but are all round. Got mine on fleaBay for under a fiver. EDIT: wingertaz has them at £3.50 each.
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hi there this past white i think its used to help heat transfer between a transistor and its heat sink. Though might be of use to you to help in cooling of your motor. As were to get you could try maplins on rs. john
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Right do you know any mechanics or alternatively go to your local motor factor and buy some COPPER brake pipe in 4.75mm and make your own by winding round the motor you should get a roll for a fiver
Stavros
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If you are going to make one , wind it on a former about a 1/4 of an inch smaller or about 4mm because you cannot get a tight fit using the motor as they spring a bit.
Peter
OR they do with me
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I do have some copper tubing this is why I asked if there was a preference, as I have seen the aluminium ones on flebay.
Brian
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Have a look at the link they have some more on the next page ,if you are stuck for space below
but can be slow delivery
Peter
http://www.astecmodels.co.uk/products.php?posted=1&selection=accessory
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Thanks for that link Peter, once again aluminium is the prefered material, must be the cost.
Brian
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I think the heat transfer is better with ally , copper takes time to heat up and then again to cool down, ally is much faster .
Peter
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Fill the tube with sand, and tape the ends closed prior to bending.
This will prevent the tube from crimping or flatting as you wrap the coil.
8)
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Another cheap "filler" like Umi's is water. fill tube and bung in freezer, or if you can plug the ends, water. (Old school physics, you can't compress a liquid.)
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I have fitted a coil from a refridgerater in the past. Very flexible, can be fitted around almost any size of motor. It worked well for me and very cheap from the local shop.
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Peter
You are most probably right regarding the heat transfer of ally, most large electric motors have ally bodies. I like the look of the Astec ones the saddle bag ones are the shape I was after, time to flex the friend.
Thanks to everyone for the advice
Brian
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Beware of the white heat sink compound. There is a widespread mistaken impression that the stuff improves heat transfer between metal objects. The truth is, it is better than air. It was originally intended to improve the thermal transfer between semiconductors and heat sinks. If the surfaces of both had been machined perfectly, there would have been no use for the goo. The approved use is not to slather it on, just apply the least possible and spread well. It then fills the air gaps left by minor imperfections.
The advantage of aluminium over copper is cost and weight. Copper has a better thermal performance, but is heavier and usually more expensive, also when cooling coils were first being mooted, there was a world shortage of copper, and why many houses got galvanised plumbing and cables all over the country were made from aluminium.