How hot can a motor get.

[macace123]

my pro boat 1800kv motor seems to be running hot. like 120 to 130 is this safe or should i worry help thanks.

[Doby]

Nothing wrong with those temps, but be careful, if you are seeing those temps and the water/air temps are cold at this time of year, make sure you check them consistently as the water and air temps get warmer as the season progresses.

Check your connector temps as well.

[hydro_pyro]

With a water-cooled motor in cold water, you'll never know just how hot the motor windings are really getting. Mine gets hot enough to make a slight burnt smell after a hard 6s run, but Horizon tech support assured me this is normal when breaking-in a new motor on 6s.

[TristanJones]

"breaking in" is it a brushed motor? Not really anything to break in in a BL motor....

Ive got a cheap nasty HK motor here Ive seen at 130degC a good minute after I backed it down and brought it in, it still seems to run fine, but I wouldnt do it to a motor I cared about!! There was a bit of blue smoke in the hull after the run, but I had just oiled the bearings that morning and i put too much in, it smelt like burnt oil. (cant be good for bearings... let alone windings.)

80degC MAX for ESC and motor. 50C MAX for Li-po is what Im hearing from the more experienced guys.

[Fluid]

If the temperatures you recorded are representative, then no problem. They should be measured on the endbell as soon as possible after bringing the boat in. (Holes in the endbell allow internal temps to be taken with care.) Measurements on the cooling jacket are useless. Temperatures above 150-160*F on the endbell can damage the magnets on cheaper spec motors like the OP's, 80*C is too hot for them as demonstrated by several of my club members. Above 185-190*F will damage about any magnet. A motor with damaged magnets will still run, but its efficiency is reduced and it can burn down an ESC. Then the boater blames the ESC when the problem was really a bad motor....

Guys who report temperatures as "cool" are doing a disservice to the board and can cause newer boaters to worry unnecessarrily. What is "cool" anyway? 75*F? 95*F? 110*F? Anyone who says their equipment comes in "cool" after running on a hot summer day defies the definition most folks think of as "cool".




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[macace123]

Thanks for the info guys.

[TristanJones]

I think I should clarify that the 130degC (266*F!!!!) temp I saw on that motor is not what im saying is safe! Thats just how hot I have seen a BL motor of my own and had it still go "ok" afterwards.

Definitely not what Im calling safe, recommending, or how I run my set ups. I was just having a play with a few things and had no water cooling on the motor and thick weed in the water causing all kinds of issues....

Hell... Ive seen a 12V brushed motor with just under 50v in it, still running with fire coming out of it. though we didnt back it off till it failed completely, no idea how hot it was, other than FKN hot, unfortunately didnt have temp gun on hand... though it would prolly have not had enough range to measure it anyhow.

[Make-a-Wake]

My target temp on the endbell after a run is 135*. Use the 5 second rule if no temp gun handy everytime, 5 seconds of the finger til you have to pull away cuz its too hot is about 135*

[hydro_pyro]

"breaking in" is it a brushed motor? Not really anything to break in in a BL motor...

By "breaking in", I meant bringing the enameled windings to full operating temperature for the first time. Kind of like that "new furnace smell" when you fire it up for the first time.

[Cooper]

I understand what you mean by a break-in. Any kind of mechanical device will definitely benefit to a break in period, just running up close to operational speed then letting cool, settle, ect. We do have bearings in these things, the only mechanical thing to break in. And yes oil of some sort is usually on manufactured objects, leftover from manufacturing. Will burn off as its usually a coolant or lubricating oil not intended for high temps thus the burnt smell. Normal. But in my opinion most of these motors aren't substantial enough to worry about seating bearings or such, run and gun. I have always done the five second rule also, not on the cooling jacket like said above, try and get your finger on the end bell or shaft. It's usually the cheaper motors that suffer from hotter temps, higher cost usually equals higher quality and higher tolerances. (Usually!!!! :) I've never really got actual hard data on temps so I can't really give you an answer numerically. If you have to pull your finger right away then something is about to expire.

[Shooter]

They should be measured on the endbell as soon as possible after bringing the boat in. (Holes in the endbell allow internal temps to be taken with care.) Measurements on the cooling jacket are useless.
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Absolutely! Aim at the windings through the endbell holes. Also, take temps at the same location every time so you have a reference. For me I've found the hottest point on the windings nearest the wires. I've been running 140-150F AT THIS LOCATION with an AC 2030KV motor and some fairly large props after heat racing. So far, so good after over 30 or so runs.

[Make-a-Wake]

My target temp on the endbell after a run is 135*. Use the 5 second rule if no temp gun handy everytime, 5 seconds of the finger til you have to pull away cuz its too hot is about 135*

Sometimes I wonder why I even post, my method and parameters are spot on, tried and tested in the real world. Makes me wonder if the OP even reads the replies.

[macace123]

thanks for the info guys