RailPro > Finished RailPro Installation Examples
O Scale Weaver SD40-2
ron045:
--- Quote from: CPRail on July 05, 2021, 09:11:15 AM ---Looking good!
I'm curious, are there any O Scale SD40-2s with body mounted pilots and couplers? It looks like both the Atlas and Weaver ones have truck mounted pilots and couplers, no doubt to accommodate the 3-rail curves.
Ian Lisakowski
Winnipeg, MB
--- End quote ---
You are correct, this has truck mounted pilots. You can buy 2 rail engines that have fixed pilots. I have some MTH F7's with fixed pilots and kadee couplers. Sometimes those can be troublesome even on my O-72 curves.
Ron
ron045:
Anyone see a problem with this spacing?
The black part that says, "May be hot" is 3/16" away from the battery.
The width of the engine is such that I really do not see a mounting alternative.
Thanks in advance for your thoughts and ideas.
Ron
G8B4Life:
It going to be a "depends" situation. From the LM-3S-G instructions...
--- Quote ---Step 2 – Mount the LM-3S-G in your locomotive.
IMPORTANT: Module must be mounted level with the RailPro logo pointing straight up in order for it to have proper heat dissipation. You need to be sure there is 1/8" of space on the four sides of module and a 1/2 inch of space above the module for proper cooling. The module can be attached with double face tape to the bottom of the LM-3S-G module.
TIP: If the auto set for the Motor Full Load current is set up to less than 1500mA you can mount the module in any orientation.
--- End quote ---
If the loco doesn't draw much power you might be ok but until you know what it draws it's hard to say. I'm guessing that the free space in the shell to the right side of the pictures is is not usable for the LM due to it's size? One possible solution could be to channel the heat away to an area with more air space (eg, to the right side of the LM in the pics). You could "glue" some formed copper sheet with heatsink compound to the heatsink of the LM. Then you could put a thermal insulator between the copper sheet and the battery.
I do not know how well if this would work, if at all (they do this sort of thing inside laptops though so it has some merit) but it's an idea.
- Tim
ron045:
Thank you for the reply.
Unfortunately the space to the right and the left are mostly used up by the can motors.
When I ran the motor current test is read over 2100ma.
I was fiddling with it last night. The battery either has to be mounted on its side or sit at a 45% angle. It's just too wide to go in flat. That was the best battery configuration available. Others were too big or too bulky. I even cut out two mounting posts just to get this to fit.
I can mount the module as written, but I would not be able to achieve 1/8 inch spacing on the sides. It's a perfect (loose) fit.
I remember reading those instructions you posted before. Why does the orientation of the module matter based on the full motor load current? What bad things could happen with a sideways mount and motor current over 1500 ma?
Thanks
Ron
G8B4Life:
Having less than 1/8" clearance on the sides (for the flat mount method) would possibly be ok, there would be far less heat radiating from the sides than the top.
The mounting orientation is all to do with heat dissipation. I'll let someone smarter than me get into the specifics of why (I know other things like power supplies also have different ratings depending on the orientation they are mounted) but in your case 1500mA generates less heat than 2100mA.
I don't know what the bad thing that could happen with a vertical orientation and more than 1500mA of current being consumed LM wise is; again someone smarter than me will have to get into that but what I can see as the bad thing that could happen with how it set up in your pictures currently is that the heat generated could melt the battery casing. This is why I suggested a heat pipe as a possible solution.
Another possible solution, though far fetched it may seem would be a miniature fan that blows down the length of the body installed near the hot end of the LM.
- Tim
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