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2650Kv motor on 6S

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Old 02-08-2019, 12:22 PM
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Originally Posted by ta_man View Post
Temperatures are not the only issue. Castle specs a maximum of 60,000 RPM for the 15 series motors (it is printed right on the end opposite the output shaft).

A 2650KV motor on 6S will be turning 66,780 RPM unloaded. So it is possible to get it over 60,000 under load on 6S which could cause spontaneous disassembly of the components of the rotor. Maybe not the first time you run it that fast, and maybe never, But it is a possibility.
Heat is what you really need to worry about. It's not like the parts inside realize they are at 60krpms and exploded. I have seen a few 10th scale motors fail no where near the 100,000rpm limit due to heat. Most were actually closes to 60krpms when they're rated at 100k.
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Old 02-11-2019, 07:02 PM
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Originally Posted by Zinergy View Post
Heat is what you really need to worry about. It's not like the parts inside realize they are at 60krpms and exploded. I have seen a few 10th scale motors fail no where near the 100,000rpm limit due to heat. Most were actually closes to 60krpms when they're rated at 100k.
The parts don't "care" what the RPM is, they "care" whether the centrifugal force trying to separate them from the rotor shaft is greater than the strength of the materials that hold them in place. That's why you see that the bigger motors have lower max RPM limits than smaller ones.

That's not to say that heat is not the cause of many motor failures. And it is also true that the hotter the motor gets the less strength the adhesives (holding the magnets on the rotor (for a 4+ pole motor)) have. But you can still destroy a motor that hasn't warmed up by spinning it too fast.
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Old 02-11-2019, 09:26 PM
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I havent seen the rotors that have a can containing the magnets come apart but im sure they do. I have seen 100ís come apart that have the glass wrap. It comes from over spinning for the balance class they were designed too. im sure heat doesnt help but I can confirm just as many that are under temp fail as ones that are over temp.

I doubt its legal for a stock class but im not sure. Balancing a rotor slightly extends the RPMs that cause a delamination.
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