Hi Folks,
Firstly, Merry Christmas!
Secondly, I’m about to set up a revolution trackside RX. I’ve got the fan unit for it but I noticed there is no Air-Outlet around the plastic shroud/case. Anyone modify one of these sets to let more air through or do you find them fine with just the fan turning on top of the heat sink?
Cheers
Mike
Hi Mike, if this is the Revolution Trackside Receiver you have, in my experience, you don’t need a cooling fan for it.
I’ve run them in an enclosed boxcar and never had them overheat… In an enclosed area, I just took the case off…
Thanks for the info Stan. I am planning on using it in a box car.
Sounds great, Mike… It works like a charm that way…
Here’s an image from Dave Bodnar’s site with the case on, case off and with one old and one new smaller receivers…
As you can see, Dave has soldered the power wires on the input tabs in the upper left corner. BE AWARE of input polarity on that unit… Positive to Plus, Negative to Minus. (http://www.largescalecentral.com/externals/tinymce/plugins/emoticons/img/smiley-cool.gif)(http://www.largescalecentral.com/externals/tinymce/plugins/emoticons/img/smiley-smile.gif)(http://www.largescalecentral.com/externals/tinymce/plugins/emoticons/img/smiley-laughing.gif)
Precision RC recommends a fan.
And you have it apparently.
I talked to them about this issue, and I recommend blowing air down, and drilling some holes in the plastic case.
The alternative is use spacers to space the fan away, but I don’t like that idea as much.
I’ve had a lot of experience with heat sinks and fan cooling, first was in 1975 with a small company called Hewlett Packard.
Greg
Why can’t you turn the fan upside down and simply assist the already rising hot air to vent faster vertically?
Agree…Did precisely that Tony…
Still a problem, the fan is basically sealed to the housing, there is no air flow in or out of the now-sealed enclosure… the plastic housing needs vent holes that route air over the base of the cooling fins. So changing the fan direction does not help. If you don’t want to drill the holes in the plastic, then put some 1/8" spacers between the fan and the housing.
Also, you get more air flow with pressure, not vacuum…
But in this case, you probably are not running near the max output, so the first step in cooling has been accomplished, break up the boundary layer (zero airflow near the heat sink surface)… that is the most significant part of cooling this situation. I’m sure you are fine.
Greg
Thanks for the replies gentlemen.
Greg, you mirror my thoughts exactly, After examining the unit I saw no significant air exits. My experience in this area comes from RC aviation. When you install a cowl over an engine, there must be outlets for air to leave the engine cowl and create “flow through”. I.e, the cowl flaps on old-air cooled radial engines. I know this Rev unit will have no problem with one loco but I want it to power a double-headed set of Aristo RS3’s inside a trailing boxcar.
Now the next issue…how to best get “clean-cool” air into the box car? I might have to turn the unit upside down, with the fan on the floor of the box car drawing air upward through holes and blowing it through the RX housing.
P.S. - I like the idea of using spaces to open up the case. Will have to do some testing.
Cheers guys and happy new year!
Mike Lafferty said:
Thanks for the replies gentlemen.
Greg, you mirror my thoughts exactly, After examining the unit I saw no significant air exits. My experience in this area comes from RC aviation. When you install a cowl over an engine, there must be outlets for air to leave the engine cowl and create “flow through”. I.e, the cowl flaps on old-air cooled radial engines. I know this Rev unit will have no problem with one loco but I want it to power a double-headed set of Aristo RS3’s inside a trailing boxcar.
Now the next issue…how to best get “clean-cool” air into the box car? I might have to turn the unit upside down, with the fan on the floor of the box car drawing air upward through holes and blowing it through the RX housing.
P.S. - I like the idea of using spaces to open up the case. Will have to do some testing.
Cheers guys and happy new year!
Would that not tend to draw in dust from track level?
What about mounting the fan perpendicular to the heat sink, on the edge of the case, and blowing air across the heat sink?
As to fan direction. Simple logic tells me that if hot air is already rising, assisting it is much more efficient than fighting it.
Heatsinks work by having cooling air moving over them. So if there is no way air can move across them they are simply relying on radiance to remove excess heat, which is not going to work very well.
Greg is right, in this case it doesn’t matter which way the fan faces.
There is simply no way of passing air across the heatsink. What sort of cockamamy design is that? You would do way better by mounting the fan on the side and have the airflow moving parallel to the fins. Suck or blow doesn’t really matter then.
Mike, try it with no vents, if the heat is not great, the additional surface area of the boxcar may provide enough cooling. With the fan going, you will have enough air currents to expose the warm air to the inner surface of the box car and let it try to radiate the heat out. Also, since it will be moving most of the time that will help break up the boundary layer on the outside of the box car.
Well, the weak convection currents of heat rising from the heat sink are inconsequential compared to the forced air flow created by the fan. But as I stated, positive pressure from the fan to the heat sink is much more effective than trying to draw air across it. I cannot explain why pressure works better than vacuum, but have done extensive testing.
Yes, I know pc’s have an exhaust fan, but that’s for a different reason, again a thing we found out in 1975 at HP. You will notice the critical components (CPU, GPU) have positive pressure on the heat sinks.
Greg
You could put it in a stock/cattle car …
Yea, them cars are already ventilated. Use a moo sound card to cover the noise of the fan, and you are all set.
