safe motor temperature

[justski]

Hi what is a safe temp to run at

[Capt'n Crash]

It really depends on the motor some can operate safely at higher temps than others but from what I've read 55C or 130F is fine anything above that is pushing it

[justski]

Thank you very much...Capt'n Crash

[fweasel]

I also take run time into consideration. If I get a full 5min run on a given setup and the motor comes back at 120*, no problem. If I make just a few quick passes and the motor is already seeing those temps, it's too hot, for me anyways. The problem with the heat is that it will demagnetize the motor magnets. Even if you don't grenade a motor after one hot run, you can decrease the motor's output cumulatively over time by running it too hot.

[Fluid]

Where are you measuring that temperature? The endbell? The PTO end? The side of the can? The cooling jacket? It is usually the magnets which are damaged first, and magnet temps above 180*F will damage most. Cheap motors, not even that much. But that is magnet temperature, not external temperature. So much will effect external temps (like can venting, motor size, cooling efficiency) that it is tough to make an accurate guess. Personally I have used 145*F as a max temp - with quality motors.

Some outrunners claim to be able to withstand over 200*F on the magnets, which are much easier to measure than in an outrunner.

[justski]

Thank every one for the help I'm running a 44 inch delta sniper with a Swordfish Pro+ 300A.Octura x457/3 .motor is a TORO BEAST X528 2Y 7350w...on 10s...I ran it 2 laps then checked the temp it was at 85F then I ran it full out till the power quit..the motor and ese was at 105F...the batterys were at 128F

[f252br]

why so low? i mean my surface rc motors can got 170F with no issue. alot of racers say 160 is the sweet spot. i dont get it

[Fluid]

The critical magnet temp depends on the motor. Magnet type/quality makes the difference, as does any can venting. Remember that the magnet temperature will be somewhat higher than the can temp. Every time the magnets exceed the critical temperature they lose some strength. Weaker magnets means a higher Kv which can cause more overheating and more magnet damage. Neu used to say that over 180* would start to damage their magnets, and they used very high quality magnets. The term “sweet spot” is misleading since the cooler the motor the more power it will make, given the same amp draw. And if course car motors don’t work as hard as boat motors do.


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[fweasel]

And of course car motors don't work as hard as boat motors do.
.

Exactly

[f252br]

so if car motors dont work as hard then they should run cooler but they dont...
i ask the manufacturer about their motor temps...

[martin]

You think a motor gets hot in a car, try running a motor in a boat with no watercooling & see how hot they get within a very short period indeed. Far far hotter than you will see in a car to the point of destroying the motor in the boat along with other components being possibly damaged, all due to motor being in a sealed compartment in a boat with no airflow at all + the very high amp draw you will get powering boats with direct drive ( no gears in boats as well )through water.

[Capt'n Crash]

The other day I measured the temp on my little FT009 brushed motor and it runs consistently at around 152F with no ill effects but I don't think I'd care to see that with my other brushless FE boat motors.

[plinse]

Be careful, cheap brushed motors often use ferrite magnets. The ferrite magnets are much weaker then NdFeB Magnets but their stability against demagnetisation rises with higher temperatures while the stability against demagnetisation sinks on NdFeB magnets with rising temperature. The remanence which means the magnetic flux sinks on both magnet types with rising temperature so the operation efficiency of the motors sinks with rising temperature.

[Capt'n Crash]

plinse...good info to know about ferrite magnets but as you say they are cheap brushed motors.
I get a solid two seasons running out of them before they start to loose power and at $12 a pop for a new motor I'm not too concerned.