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Old 09-08-2008, 09:51 AM   #1
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Questions?? Brushless Motor Failures and Motor Coolers

Problem solved! It appears the motor chillers and canned air upside down do cause the motor failures. Thanks all for the insight.

Last edited by or8ital; 10-03-2008 at 11:19 AM.
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Old 09-08-2008, 10:03 AM   #2
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Our track has experienced a large amount of 10.5 brushless motor failures. All brands. Some people a lot more then others. One of the things I have noticed is those that use motor coolers (or canned air upside down) before a race seem to experience the most failures. I have a theory that the motor coolers are causing it as a result of rapidly changing the temp of the motor.

I was wondering if anyone else has noticed this or had thoughts?

Thanks.
dont over gear them and you wont have any failures
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Old 09-08-2008, 10:11 AM   #3
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dont over gear them and you wont have any failures
Some of the motors failing are geared very conservatively (for example this weekend someone had a Losi 10.5 geared at a 5.2 FDR fail). Some of the ones that have lasted all summer are geared very aggressively. The difference I've seen is just the motor cooler. But thanks for your contribution.
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Old 09-08-2008, 10:45 AM   #4
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Some of the motors failing are geared very conservatively (for example this weekend someone had a Losi 10.5 geared at a 5.2 FDR fail). Some of the ones that have lasted all summer are geared very aggressively. The difference I've seen is just the motor cooler. But thanks for your contribution.
maybe cooling the motors is creating condensation inside the motors making the windings short out??
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Old 09-08-2008, 10:50 AM   #5
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i agree the rapid temp change may cause issues
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Old 09-08-2008, 10:59 AM   #6
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maybe cooling the motors is creating condensation inside the motors making the windings short out??
Yeah that could be the case too.

One of the guys hit hard stop using his this week. I guess after a few weeks we will be able to tell better.
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Old 09-08-2008, 02:36 PM   #7
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the problem you get with computer hardware failure is rapid temperature change, not the high temperatures themselves. maybe that's a similar effect?
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Old 09-08-2008, 02:52 PM   #8
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How do the motors fail? Do they burn up, or just stop running? Has anybody checked to see if Hall Effect sensors are sensitive to rapid temp changes?
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Old 09-08-2008, 03:00 PM   #9
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i have been using a motor cooler on my bl stuff for 3 years, not one failure.
but what would i know, i am just an amature.
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Old 09-08-2008, 03:10 PM   #10
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They burn up I believe. I will ask the people who have had it happen to find out what exactly the end product looks like.

This is outdoor racing on a large track for what it is worth. I was talking to one of the racers who said one of the local fast guys has been using one inside for a long time without problems. One of the guys with the problems though (11 motors this summer) is one of the other top racers. He is also the only one that uses one of those motor chillers. Everyone else uses canned air upside down. Amongst the 15 regulars in the class there have probably been 20-30 motor failures.

If its the condensation theory then perhaps indoors would be less suseptable to that b/c the indoor temp is less.
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Old 09-08-2008, 03:34 PM   #11
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maybe cooling the motors is creating condensation inside the motors making the windings short out??
This would be my guess as I had a 540 can motor failure this summer which I thought had a bit too much water in it.
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Old 09-08-2008, 03:48 PM   #12
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Default motor failure

i think you half to find out what was failing was it bearing or did they short out from condensation , ive seen alot of bearing failures this year at our track where nobody is doing the motor freezing thing and we are running 13.5s and mod motors ,
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Old 09-08-2008, 03:55 PM   #13
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i think you half to find out what was failing was it bearing or did they short out from condensation , ive seen alot of bearing failures this year at our track where nobody is doing the motor freezing thing and we are running 13.5s and mod motors ,
what happens when a bearing fails? Seize and burn up? A lot of these were new or lightly used motors.
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Old 09-08-2008, 04:29 PM   #14
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I would guess the enamel on the wire isn't liking to be rapidly cooled and then heated and thus cracking. Once it cracks the windings will start to arc and short and fail.
You would really have to break one open to tell whats happening though.
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Old 09-08-2008, 05:08 PM   #15
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Wow, that is a lot of motor failures...

I've been running 10.5 outdoors with ambient temps over 100f
my motor reached over 200f gearing the motor at final drive of 5.4
I just put an lrp fan on the motor and was good for 20f drop at the end of the run...
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