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Old 11-09-2002, 09:00 AM   #31
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Default Heatsinks and CPU's

What nobody has yet to point out, is that heat will rise if it greater than the surrounding air temperature. Therefore a heatsink, whether it be mounted on a computer chip or a R/C car motor. Will help pull heat out of the object that it is attached to and dissipate that heat into the surrounding air. The effectiveness of a heatsink will depend on how well it contacts a surface and how much total surface area (fins) is avalible to dissipate that heat. This is why some people suggest using heat sinking compound between the motor and the heatsink. I would not. It doesn't really dry and can be very messy to work with.
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Old 11-09-2002, 05:07 PM   #32
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Lucky I have a 03f... plenty of airflow up front
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Old 11-09-2002, 06:00 PM   #33
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Default Re: Heatsinks and CPU's

Quote:
Originally posted by popsracer
What nobody has yet to point out, is that heat will rise if it greater than the surrounding air temperature. Therefore a heatsink, whether it be mounted on a computer chip or a R/C car motor. Will help pull heat out of the object that it is attached to and dissipate that heat into the surrounding air. The effectiveness of a heatsink will depend on how well it contacts a surface and how much total surface area (fins) is avalible to dissipate that heat. This is why some people suggest using heat sinking compound between the motor and the heatsink. I would not. It doesn't really dry and can be very messy to work with.
I agree totally popsracer and thanks for coming up with another reason why heatsinks do work regardless of airflow, provided that they make good contact with the surface. As i mentioned before most early computers had heatsinks on their CPUs without fans mounted on them with little to no airflow in the box.
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Old 11-10-2002, 09:55 AM   #34
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I believe (and this is my opinion of course) that a heatsink of any size will indeed help. Will it be measurable or of much benefit? Who knows, only one way to find out.

There was a statement made about not advertising the use of a heat transfering compound being misleading. I dont think so at all, Associated recommends using Reedy batts and motors, are there faster motors out there? Probably, are they misleading you, not at all.

With the heatsinks the material used will never be perfectly flat/smoothe because of the metal or the machining of the material. This compound helps to fill in these pores/imperfections to increase the surface area and transfer of more heat. I will guarantee that if you purchase some Arctic Silver compound you will see a decrease in you temperatures! You can find it at www.2cooltek.com . Its not cheap but it is great stuff. In my computer it dropped the temp 3* C just by changing from the Intel supplied compound to the Arctic Silver compound. This stuff doesnt really harden like some of the "white stuff" does but doesnt run either. It is easy to remove with a rag or paper towel when you want to pull and clean your motor. It isnt cheap but if you are looking for something that will decrease the temperature it will work. Is it enough to make a difference? I dont know. Any time you can increase the surface area the efficiency will rise, so a heatsink regardless of how big will make a difference. I wouldnt use one that covered the vents of the can though. I'm going to machine the FT clip on so that it doesnt cover the vents. I dont have anything to measure the temp other than my finger but I'll know if its getting hotter, cooler maybe not.
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Old 11-10-2002, 03:47 PM   #35
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Quote:
Originally posted by madweazl
I believe (and this is my opinion of course) that a heatsink of any size will indeed help. Will it be measurable or of much benefit? Who knows, only one way to find out.

There was a statement made about not advertising the use of a heat transfering compound being misleading. I dont think so at all, Associated recommends using Reedy batts and motors, are there faster motors out there? Probably, are they misleading you, not at all.

Thanks Madweazl,
I love a good debate.
There is a big difference though between recommending something, as in recommending the use of a particular motor with a car, and not recommending or instructing to use something that a product needs for it to function as it should.
It is my understanding that the curved heatsinks that fit around the can (which seem to be the centre of this discussion) are made by the manufacturers to work as they come out of the packet, without the use of any form of heat transfer paste. It has never been brought to my attention before by the hobby store people or in the instructions accompanying such a heatsink that they are to be used with a heat transfer paste or they will not work properly.
So in my opinion if the product does not work as the manufacturer intended it to be used without the paste then that is misleading.

Steevo
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Old 11-10-2002, 04:02 PM   #36
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I believe it does perform as intended really, it does increase the surface area which can allow for more cooling. If you cover the vents (which common sense should lead you to do otherwise) youre obviously compromising the motors ability to cool itself.

This is the epitomy of racing though. You are always looking for the little "speed secrets," this probably isnt one of them but its something that you have to figure out and tinker with all the same. A product can always be improved with a crafty hand and mind. Its amazing what people have come up with over the years to go faster. I remember one year Kinwald actually got an idea for a tire buy turning one inside out. It didnt work as he'd hoped but it was ingenuity at its best! AE drivers tried the rear shock tower on the front of the car and drilled a new hole in the arms and found they liked the results (apparently the first time this had happened it was due to a lack of spare parts). It wasnt its intended use but they stumbled across something else. I see what you are saying too but I believe it does work as intended (I also think that the sink is sold as eye candy too), just not as good as it possibly can
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Old 11-27-2002, 08:43 PM   #37
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OK, now that the great "Heatsink Debate" has been concluded lets get back to How Hot is Too hot??

I just pulled apart my 10X4 Trinity motor for a bit of a clean and Inspection (it was filthy by the way).
The comm was in fairly good order but there was a slight coloring on the comm. It was not severe but there was a slight rainbow of blue, orange and yellow.
I am assuming that this is just normal as there was no grooving from the brushes or signs of burning or uneveness of the comm, just a slight rainbow of color.
One other thing, the brush wires also appear to have taken on a slight golden appearance.
As usual all your thoughts and experiences are appreciated.

Steevo
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Old 11-28-2002, 05:03 AM   #38
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Blue discolouration of the comm is a sign of overheating - normally a skim will freshen the surface up though.
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Old 11-28-2002, 10:43 PM   #39
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So then even the smallest trace of blue coloring of the comm means that the motor is overheating??
Could the fact that the motor was so dirty inside have caused the problem??

Thanks
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Old 11-28-2002, 11:54 PM   #40
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Default Motor overheating

Steevo;

The brushes are usually the first ones to show signs of overheating. Inspect the brushes often. Rebuild your motor (or have it done) then I would gear down 2-3 teeth on your pinion gear. The brush springs should probally be replaced too. If the Motor is getting hot enough to discolor the Com, then the springs may have been weakend from the heat.
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Old 11-29-2002, 01:59 AM   #41
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Thanks,
I have just pulled down the motor and cleaned it. The brushes and springs appear to be in good condition but I might try gearing down and see how it goes.
How should a comm look after normal wear and tear?? I would have expected some discoloration. Its not that I am doubting what you are saying in any way because I am sure that you have a lot more experience than me. Its just that I would have thought that just a small and feint rainbow of blue and yellow and orange on the comm would be normal.
Does the fact that the brush wires are turning a feint gold color also mean that the motor is overheating or is this within normal limits.
I am currently running a 96spur/24 Pinion on my TA04 with a 10X4 Motor (FDR is 6.01:1).
According to rollout figures this should be the right gearing. What is your opinion???
Thanks for your help in advance

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Old 11-29-2002, 02:34 AM   #42
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I recently watched a Pro at our track doing a little R&D on new motors. He had his heat gun with him, and basically ran different motors & different gear combinations until the car would just stop. The main problem he was having,was all the solder coming off the engine (brushes & wires together). When the car would stop he would run out and get it, temp the com & brush hood, then bring it back to the pits to check out what failed. The temps he was getting at the com & brush hood where right around 300deg. His solution? Mount a small, low amp draw fan to the chassis blowing directly on the comm/brush hood. The results? He could fnish his heat without failure & lowered temps by 30deg. Just my 2 cents.
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Old 12-04-2002, 08:17 PM   #43
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Hi all...in new at this motor rebuilding thing....everytime I run my motor in after a new comm cut and brushes (I've tried this 3 times)...my motor gets really hot...even with no gears connected to it and running it at low speed...if I press the trigger on my transmitter too hard....the sparks on the comm gets larger and eventually smoke comes out...
When Im using the motor it seems to get really hot no matter what gears I use...
Im using and Orion Core Stock....is this normal?
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Old 12-04-2002, 08:44 PM   #44
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Default Over/under geared

Steevo; (my dad calls me that)

Judging by your comments on the condition of your motor and the # of turns (10x4). I think you gear ratio is way to low (numerically)
Most motors in that turn range should be in the mid 7.00's or higher for a FDR, at least!
I run 7.00 to 7.20 with my Stock motors.

BuggZI;

You need to break in your motor/brushes with LOW voltage. 3-4 volts for about 3-5 minutes is what most people use. Make sure you have the right brush springs for your application.
The Core Stock's run hot like the Reedy MVP's.
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Old 12-04-2002, 08:58 PM   #45
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Hi Popsracer...
I am using the standard springs that came with the motor...
does that mean what im seeing is normal behaviour?

Can you suggest some other stock motors that don't run that hot?

Thanks
Paul
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