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Old 01-15-2010, 06:16 PM   #1
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Default how hot should a brushless motor get?

3300kv, I've tested it out with NO LOAD, motor is simply free spinning, which I assume should run a fair bit cooler.

how hot would you expect it to get?

thanks.
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Old 01-15-2010, 06:41 PM   #2
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I need to know this asap please
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Old 01-15-2010, 06:46 PM   #3
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I don't let mine go over 170F. I would not recommend running that motor without a load on it for very long if at all, it's bad for it like running a nitro motor with no load
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Old 01-15-2010, 06:50 PM   #4
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it's bad for it like running a nitro motor with no load
care to explain?
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Old 01-15-2010, 06:52 PM   #5
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Brushless motors will actually get quite hot free spinning. I have seen them climb as high as 150F in a matter of seconds with no load. Plus it is not advised by most motor manufacturers as it can be detrimental to the magnets. Novak has something about this on their website and they even show what can happen if a motor is free revved too much.
Whatever you do it is recommended to not let most motors over 175F, some can sustain higher but it is generally not recommended.
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Old 01-15-2010, 06:55 PM   #6
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now can an unloaded motor run hotter than a loaded motor?

can someone please explain the theory behind that
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Old 01-15-2010, 06:58 PM   #7
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Yeah sorry I guess I should have elaborated on that. Yeah I was taught when I first got into brushless motor ahwile ago that free spinning the motor (a friend at my track caught me doing it to my very first brushless setup) was very bad for the rotor. I have not personally seen what happens to them if you do it but for what good brushless motors cost I did not bother to tempt fate and find out hehe.
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Old 01-15-2010, 06:59 PM   #8
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Yeah sorry I guess I should have elaborated on that. Yeah I was taught when I first got into brushless motor ahwile ago that free spinning the motor (a friend at my track caught me doing it to my very first brushless setup) was very bad for the rotor. I have not personally seen what happens to them if you do it but for what good brushless motors cost I did not bother to tempt fate and find out hehe.
but that would be an RPM issue on a brushless motor, not a temperature issue.

I mean, its just an electro magnet, its not going to get hotter spinning at lower RPM with no load, is it?
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Old 01-15-2010, 07:03 PM   #9
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but that would be an RPM issue on a brushless motor, not a temperature issue.

I mean, its just an electro magnet, its not going to get hotter spinning at lower RPM with no load, is it?
just wind it out full throttle and let us know what happens after a couple minutes
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Old 01-15-2010, 07:14 PM   #10
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I wont pretend like I can tell you all the "theories", I am just passing along knowledge I learned from veteran racers. When dropping a couple hundred bucks on a brushless system, and especially over $300 on an RX8 I just took their word for it haha. Also you can run the risk of hurting your speed control. I had something short out in a brushless motor last season during a 1/10 electric touring car race and the motor kept pulling power regardless of throttle position and my ESC burst into a small fireball.
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Old 01-15-2010, 07:20 PM   #11
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ok, the motor seems to be alright

its now in a firestorm, 19t pinion, 87t spur.

its not the vehicle it will be used in.

plus I'm running it off a 30amp esc, which will probably melt. haha.

just wanted to test the motor out

thanks for your time!
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Old 01-15-2010, 07:22 PM   #12
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I try to keep mine around 170*
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Old 01-15-2010, 08:15 PM   #13
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I won't pretend to know why it does it either, but will confirm that a free spinning unloaded brushless motor will heat up very quick, even at a low/moderate speed. I don't know why but they just do.
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Old 01-15-2010, 08:17 PM   #14
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I won't pretend to know why it does it either, but will confirm that a free spinning unloaded brushless motor will heat up very quick, even at a low/moderate speed. I don't know why but they just do.
yeah, I worked it out for myself too haha

I'm going to start another thread asking a fairly specific question now
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Old 01-15-2010, 08:26 PM   #15
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Firestorm brushless gearing setup questions?
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