Motors max. safe temperatures

[DISAR]

I am a bit confused with the motors max. allowable temperatures. I had in mind max. 150F (65 C) but in some motors (xcelorin I think) I saw 180 F (85 C). Also my Align 600XL motor (outrunner) with the setup that I like most, runs at 158F. Does anybody know what are the max. safe temperatures for

2 pole (Feigao, etc...)
4 pole (NEU, Medusa, Xcelorin)
Outrunners (over 6 poles)

What can happen beyond these temps???

[ED66677]

I've read that most neodym magnet can stand up to 80-95°C, above this limit, they loose their magnetism strength.

[DISAR]

Thanks ED I was looking for an answer like this, do you think that the different pole motors have the same max. temp?

This is written in the xcelorin 1/8 motor manual
Operating temperature should not exceed 190F – 205F (87C – 96C) degrees

http://www.losi.com/ProdInfo/Files/8thXcelorinMotor.pdf

[ED66677]

I think it only depends on the magnet quality, I did google it and some magnet manufacturer seems to propose very hight temp resistance Neodym magnets 150C° but that must be $$$$$$, also the winding varnish may react to heat!

[Steven Vaccaro]

About 160F max for Feigao. Any more than that on a regular basis shortens the life of the motor.

[Ub Hauled]

I've read that most neodym magnet can stand up to 80-95°C, above this limit, they loose their magnetism strength.

I have seen it as well... but some magnets are more prone to temps,
I don't like to get temps above 140-150 just to b on the safe side.
Higher quality motors are made with better mags and can withstand higher temps... but not much higher w/o some sorta loss.

[ED66677]

I fully agree, personnaly I consider overheat when I cannot leave a finger on, witch is basically above 60-65°C (150°)F, the lower the safer!

[Fluid]

Also consider where the temperature is taken. If you have a cooling jacket on the motor, don't take the temp on the jacket. Try the 'endbell' of the motor, it will be more representative particularly if you can aim through any holes in the can.

If you do over-heat the magnets they will lose strength. When this happens the motor loses efficiency - and the reduced efficiency will badly stress the ESC. You will then find that you are blowing ESCs with the damaged motor, even though the motor still appears to run fine. I found this out the hard way, lost several ESCs with the same motor that I new I had heated up to over 170F. When I got a new rotor the problem went away. I bet that quite a few burned up ESCs are caused by damaged motors....


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[DISAR]

Thanks Jay. Yes I am taking the temps on the endbell, which are much higher than on or close to the cooling jacket. Which brand of motor are you referring to?
As I understand safe way is below 140-150F and max. for some runs 155-160F

[Fluid]

I demagnetized a Hacker 540XL - quality magnets there. I once heated up a Neu 1521 to 195F and sent it in to Neu. They said it had lost 15% of the original magnet strength....



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[Mel279]

If you do over-heat the magnets they will lose strength. When this happens the motor loses efficiency - and the reduced efficiency will badly stress the ESC. You will then find that you are blowing ESCs with the damaged motor, even though the motor still appears to run fine. I found this out the hard way, lost several ESCs with the same motor that I new I had heated up to over 170F. When I got a new rotor the problem went away. I bet that quite a few burned up ESCs are caused by damaged motors....


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No wonder two of my etti's esc fried