Whats the "general" rule for motor and esc temps?

[Elliott000]

Ive adjusted my hobbywing 30a funflys to mid timing. They are spinning my AXI 2814/22 w/ 14" apc sf props, after 10 minutes of mostly hovering and some pumping in between it comes down and the motors are warm to the touch and escs are aswell. Warmer than they have been yet not hot. What is a general rule for temps.... next flight when the rain stops ill get the temps afterwards. With these motors and props the ad-6 is wicked stable and smooth. Now my only concern is heat....
Thanks Guys

 

[RotorFilms]

Hi Elliot,

I'm having the same problems, I have six AXI 2814-22 with 14" x 4.7 props. I found that three off my motors get really hot but I think it is due to my gimbal being slightly tail heavy so these motors are working harder than they would normally.

Have you found any answers yet with regards to what heat the motors can handle?

Regards,

Andre

 

[redridinghood]

I would say that the 14x4.7 props are almost too big for that motor. Use ecalc to see if thats the problem.

 

[Elliott000]

Ecalc says all is good but it is running the motors near thier max, Ive went down to 13x6.5 thin e props. Flys nice and pulls less amps.... Heat is no issue now, BUT i didnt find out how hot is to hot, Ive got myself a temp gun so i can find the exact temp... Ill post up once i finish my rebuild, Damn 2.4 signal let me down and my hexa landed blocks away on a guys truck lol... Wonder why my WKM return home didnt operate properly, I think it was intermittent signal and was confusing it

 

[RotorFilms]

Hi Elliot and Redridinghood,

Thank you very much for the replies. I've been doing a lot of research into this and I've come to the conclusion that the 14" x 4.7 props are not too bad, they are not ideal but not bad. In my research I came across "1001 Copters" where Catlord did and extremely good job at testing the AXI 2814/22 motor with various props, he published all his results for everyone too see, and the conclusion is that the best prop for this motor according to his tests is teh XOAR 14" x 5.

I'm going to be doing some testing of my own this coming weekend just to put my own curious mind to ease, but I'm confident in the results that I've seen from Catlords tests.

My craft weights 5.2kg all up, and I've noticed accoring to Catlords graphs that for my motors to generate enough lift for hover then I should be in the region of 230-250 watts which equates to about 18amps, that means still pretty safe as I will not be doing any agressive flying with this machine.

Elliot: Sorry to hear about your little mishap, I hope your copter was not damaged during this incident.

Regards,

Andre

 

[Elliott000]

280 bucks... My main concern with the 14" props lately is less with the temps and more on the amp draw coming through my distribution ring, Ill take a shot of its temp aswell, any ideas on a critical temp on solder? I would think it would be quite high. I also have fixed a secondary piece of 12 guage solid copper wire to the ring as extra "flow" .

 

[jes1111]

The "rule of thumb" for gauging temperature is: if you can't put your thumb on it without pain, it's over 55-60ºC. This temperature can be regarded as a "safe maximum" - you could go to 75-80ºC with most components without actually killing them but you'll most likely be shortening their life.

If something is hot enough to melt solder then it's probably already dead

 

[redridinghood]

Keep in mind that any bench tests you have seen are completely different than flying with a controller like Wkm that makes even underpropped motors hot.

 

[snurre]

I can confirm that Xoar 14x5 works well with AXI2814/22 on 4S. I use with CC Phoenix Ice50 lite. No temp problem.
You may be interested in my payload test video, providing some temp and amp readings. You find that video in the CarbonCore octa 1000 thread.

Cheers/ Tomas

 

[Elliott000]

Thanx for the info, definetley hauling more weight than me lol. so about 30 amps per motor eh on a full climb, I might grab some 40A esc's if i wanna run my 14's I have 30 ampers right now. I ran about 26 amps i think via my elogger when I tried

 

[DucktileMedia]

I have an XY8 with Tiger 2814's and I tried the APC 14" only to find a much hotter motor than I am used to. I was told to try switching the ESC timing to high from medium. I am using the Hoverfly Pro board. Also using Turnigy Plush 40 amp esc's. I recently switched down to the APC 12" and it not only flies better but the motors are much more normal in temperature. It's also concerning when the manufacturer themselves list the 12" as the highest output prop for that motor. but I also see SOO many people running the 14" props on the 2814 motors that it must be ok.

 

[RotorFilms]

Keep in mind that any bench tests you have seen are completely different than flying with a controller like Wkm that makes even underpropped motors hot.

Redridinghood, I agree with what you are saying, it makes sense that the motors will get hotter as they are compensating more while trying to keep the craft stable. I'm still going to be doing the test purely to see if they are drawing as much current as I think they would, because if they draw more than 25 Amps then I need to consider a different prop. But as it stands and according to the data I've seen I should not be drawing more than 20 Amps per motor which I'm very happy with.

Snurre: Thank you for pointing me to you video, very impressive I must say. Where did you get your hands on the 6000 mah Turnigy Nano Tech batteries?

Elliot: I'm going to putting a thermo couple onto my Power distribution board this weekend just to see what it gets up too, interesting that you mentioned it, I never really though of measuring it.

I will let you guys know if I come back with anything earth shattering (don't think i will though).

Regards,

Andre

 

[Elliott000]

why does the WKM have an impact on motors running hotter? Does it make more changes in voltage to the motor for stability than other controllers thus increasing the heat?
Another question along these lines, wheres the fine line on lifting capability with say 12" apc sloflys, I had read someplace that if flying in atti midstick hover and i goto manual and the heli increases altitude im over propped, if it loses altitude under propped? is this true. If so my 12" sloflys slowly come down at mid stick in manual mode and my 13" thin ez slightly increases... ill take the increase lol

 

[snurre]

The "rule of thumb" for gauging temperature is: if you can't put your thumb on it without pain, it's over 55-60ºC. This temperature can be regarded as a "safe maximum" - you could go to 75-80ºC with most components without actually killing them but you'll most likely be shortening their life.

If something is hot enough to melt solder then it's probably already dead

Here is the answer I got from an engineer at Castle Creations when I asked about max temps:

You want to try to keep the ESC temps under 210'F to keep from degrading the components... the ESC will start to shut down around 250-275' F.

For us who have difficulties with the obscure Farenheit unit:
210F = 99C
250F = 121C
275F = 135C

As for motor temp I recall reading somewhere that the bell temperature should not exceed 80deg Celsius.

/ Tomas

 

[jes1111]

Wow! I'm staggered that a Castle engineer would give that advice! Sure, the FETs may be rated to that temperature but the processor (and several other components) won't be - guaranteed! Not sure what they use, but assuming it's an ATmega, here's the manufacturer's specs: http://www.atmel.com/devices/atmega128.aspx?tab=parameters - operating temperature range -40 to +85ºC.

80ºC sounds reasonable for a motor - beyond that the shellac coating on the windings and the epoxy adhesives that are holding everything together will start to soften, quickly escalating to catastrophic failure. Naturally one should be attempting to keep everything as cool as possible. Heat kills electronic and electrical components - a fact of life!

 

[snurre]

Well, personally I would be uncomfortable with ESC temps approaching 100 dec C. I think your thoughts about staying below 85C would be sound. And preferably at lower temps, absolutely.