Hobbywing Speed Control's Overheat Protection For A Motor

[RustyUs]

Certain Hobbywing ESCs offer motor overheat protection when paired with certain Hobbywing supported motors. Has anyone ever taken the temperature of a motor's can when things got bad enough to trigger the motor overheat protection?

I've never had an ESC shut down power to the motor due to excessive motor heat. I don't know what Hobbywing's magic number is that triggers the motor overheat protection to kick in. I just do my own temp monitoring while searching for that sweet spot gearing on new setup and try to make sure to leave enough wiggle room for those hot summer days.

I'm just curious to know, because I won't let my motors get above 180°F if I can help it.

 

[DavidB1126]

I have the max10 sct in my slash and the OG max10 in my rustler. In the slash I don't run a temp sensor since the esc is too far away from the motor. Used to run the sensor on the rustler but the negative wire on the small jst ripped out of the plug so I just cut off the sensor on the esc and just keep an eye on it. (Which I am having issues with it and planning on getting a new quick run combo)

Don't know what temp it cuts out at but here is the factory setting for the older max10 sensorless systems.

Now on my race buggy with a xr10 stock spec and a g4 stock motor, the temp cutoff is probably monitored by the sensor wire. I usually track that motor at 165 to 175. Rarely do I get above 180. Unless I do long practice sessions.

 

[332_RC]

I have a Max6 G2s 4990SD combo in my K6. It's gotten to 191°, one time, before I added dual 40mm fans to the motor. I've also added a piggyback 35mm over the caps. Cool now. Both stay way cooler. I think I read somewhere it's over 200°, for that shutoff.

 

[WickedFog]

I have the max10 sct in my slash and the OG max10 in my rustler. In the slash I don't run a temp sensor since the esc is too far away from the motor. Used to run the sensor on the rustler but the negative wire on the small jst ripped out of the plug so I just cut off the sensor on the esc and just keep an eye on it. (Which I am having issues with it and planning on getting a new quick run combo)

Don't know what temp it cuts out at but here is the factory setting for the older max10 sensorless systems. View attachment 201131

Now on my race buggy with a xr10 stock spec and a g4 stock motor, the temp cutoff is probably monitored by the sensor wire. I usually track that motor at 165 to 175. Rarely do I get above 180. Unless I do long practice sessions.

Holy cow. 221°F - 257°F? That's on fire hot.

 

[bill_delong]

Temp readings on the can are fairly unreliable, though I do my best to go with the hottest reading I can record which is generally nearest the pinion gear (i.e. rotor). I believe the internal temp readings are significantly higher because the sensor board is closest to the rotor. Unfortunately, as a racer, I've been forced to disable the overheat protection on both the ESC and motor due to premature cutoffs in a race. I have immediately taken readings with the ESC at 135°F and motor around 165°F after a cutoff leaving me scratching my head. Probably no big deal for a basher to reset the ESC and go on your way, but having a DNF in a race due to a faulty cutoff is not acceptable which is why the majority of racers in my area disable the feature. I generally make it a point to get temp readings after every run and that is my indicator to know when a motor is gradually failing over time.

 

[tudordewolf]

According to this, neodymium magnets can begin losing their permanent magnetization above 80C, 100-120C for sure would have an effect. The rotor temp won't be as high as the coils & can, but it'll still get "baked" inside after a while.


If that's the case, the motor's effective kv may begin to rise, at the cost of efficiency and current draw. It could lead to a vicious cycle where the motor begins drawing more current and getting even hotter than before.

 

[hood52]

Mine shut down my 13.5 after my fan wire broke during a race. I don't know how hot it got, had to marshal the next race.

 

[RustyUs]

Temp readings on the can are fairly unreliable, though I do my best to go with the hottest reading I can record which is generally nearest the pinion gear (i.e. rotor). I believe the internal temp readings are significantly higher because the sensor board is closest to the rotor. Unfortunately, as a racer, I've been forced to disable the overheat protection on both the ESC and motor due to premature cutoffs in a race. I have immediately taken readings with the ESC at 135°F and motor around 165°F after a cutoff leaving me scratching my head. Probably no big deal for a basher to reset the ESC and go on your way, but having a DNF in a race due to a faulty cutoff is not acceptable which is why the majority of racers in my area disable the feature. I generally make it a point to get temp readings after every run and that is my indicator to know when a motor is gradually failing over time.

I'm glad you brought that (in bold) up, because I normally take a reading at endbell and on top of motor's can... whichever is hottest reading I get, that's what I go with.

According to this, neodymium magnets can begin losing their permanent magnetization above 80C, 100-120C for sure would have an effect. The rotor temp won't be as high as the coils & can, but it'll still get "baked" inside after a while.


If that's the case, the motor's effective kv may begin to rise, at the cost of efficiency and current draw. It could lead to a vicious cycle where the motor begins drawing more current and getting even hotter than before.

That's I am always leery for someone buying used motors.

I have a Max6 G2s 4990SD combo in my K6. It's gotten to 191°, one time, before I added dual 40mm fans to the motor. I've also added a piggyback 35mm over the caps. Cool now. Both stay way cooler. I think I read somewhere it's over 200°, for that shutoff.

I see the G2s are sensored now and have proprietary cable.

I wonder if anyone ever tried to warranty a "fried" motor that was paired with ESC that had overheat protection, because you would think that the sensor inside the motors would keep things from "Never allow the motor case to get 100 degrees Celsius (212 degrees Fahrenheit) because the magnets maybe demagnetized by high temperature."

 

[332_RC]

I see the G2s are sensored now and have proprietary cable.

(212 degrees Fahrenheit)

Correct. App has datalog. I'm still learning how to use it & all it's capabilities. Has real time telemetry. I also have a IR gun. I believe I read somewhere 212° F is the cutoff. Idk. Next time I fire up the K6, I'll go thru all the parameters again, it may have a temp setting IIRC.

 

[Greywolf74]

Certain Hobbywing ESCs offer motor overheat protection when paired with certain Hobbywing supported motors. Has anyone ever taken the temperature of a motor's can when things got bad enough to trigger the motor overheat protection?

I've never had an ESC shut down power to the motor due to excessive motor heat. I don't know what Hobbywing's magic number is that triggers the motor overheat protection to kick in. I just do my own temp monitoring while searching for that sweet spot gearing on new setup and try to make sure to leave enough wiggle room for those hot summer days.

I'm just curious to know, because I won't let my motors get above 180°F if I can help it.

Id back that down to about 170F max. Once the motor reaches temperatures above 175°F (80°C), the internal components, such as the windings, insulation, magnetic strength, etc. can begin to degrade, leading to potential long-term damage.

Holy cow. 221°F - 257°F? That's on fire hot.

Yeah, Id never let my ESC get that hot. you're just beggin' for the magic smoke at that temp. I mean maybe if I was racing at the worlds finals I might do that cuz Id risk an ESC to win that but yeah, not normally

 

[RustyUs]

Id back that down to about 170F max. Once the motor reaches temperatures above 175°F (80°C), the internal components, such as the windings, insulation, magnetic strength, etc. can begin to degrade, leading to potential long-term damage.


Yeah, Id never let my ESC get that hot. you're just beggin' for the magic smoke at that temp. I mean maybe if I was racing at the worlds finals I might do that cuz Id risk an ESC to win that but yeah, not normally

And why I take the readings on the endbell of the motor which is sometimes a good 20° hotter than what reading I get on the long side of the can (like pic below).

The only two times I ever destroyed a motor from heat was when a bearing blew, and I didn't realize it. Neither of the motors were connected to an ESC that had overheat protection and part of the reason why I started this thread. Just wanting to know at what temperature does overheat protection kick in and if my motors could have been saved.

I have not heard back from Hobbywing yet. I thought maybe I'd get a quicker answer here on RCTalk.

 

[WickedFog]

And why I take the readings on the endbell of the motor which is sometimes a good 20° hotter than what reading I get on the long side of the can (like pic below).
View attachment 201461
The only two times I ever destroyed a motor from heat was when a bearing blew, and I didn't realize it. Neither of the motors were connected to an ESC that had overheat protection and part of the reason why I started this thread. Just wanting to know at what temperature does overheat protection kick in and if my motors could have been saved.

I have not heard back from Hobbywing yet. I thought maybe I'd get a quicker answer here on RCTalk.

I usually check the entire can. 3 to 4 spots. Only takes a blip of the trigger. Let us know when you hear back.

 

[RustyUs]

From Hobbywing's Tech Support:

Hello,

External temps of around 190-200F are typical. However it's "not always the same" as there is not a fixed value.

Seems like an odd answer, but the truth of the matter is temperature protection is based on an internal Temp, and that internal temp, will vary a bit depending on the "how" it gets to that temp. Meaning simply, how fast or slowly it reaches it's max temp. These temps effect things differently so the "hard line in the sand" for the cutoff, moves around a lot and isn't always exactly the same .

LOL. Well, that answers about nothing.
So, I'll just keep doing what I'm doing and shouldn't have any issues.

 

[Greywolf74]

From Hobbywing's Tech Support:


LOL. Well, that answers about nothing.
So, I'll just keep doing what I'm doing and shouldn't have any issues.

I believe what theyre trying to say is the rate at which the ESC heats up (whether gradually or quickly) influences how internal components respond. A slow rise in temperature might result in different heat management behavior than a rapid increase. The internal components, including capacitors, FETs, and the processor, may have different thermal tolerances, and thus the thermal cutoff isn't always at a fixed external temperature. Not that that helps really.

That being said just keep it below 170F externally and you should be fine.

 

[Hornet68]

And why I take the readings on the endbell of the motor which is sometimes a good 20° hotter than what reading I get on the long side of the can (like pic below).
View attachment 201461
The only two times I ever destroyed a motor from heat was when a bearing blew, and I didn't realize it. Neither of the motors were connected to an ESC that had overheat protection and part of the reason why I started this thread. Just wanting to know at what temperature does overheat protection kick in and if my motors could have been saved.

I have not heard back from Hobbywing yet. I thought maybe I'd get a quicker answer here on RCTalk.

What sensor are you using. Where is it sold?

 

[nino]

Some hobbywing motors have an internal sensor that connects to the (also hobbywing) ESC via a small 2 pin connector. Proprietary stuff. Although some chinese motors have started to include the sensor too (Rocket e.g.).

 

[RustyUs]

What sensor are you using. Where is it sold?

The old EZRun motors had built in internal temp. sensors and the 2 pin connectors to pair with EZRun ESCs...

The newer EZRun ESCs and motors are now sensored with built in temp sensor. The temp cable is a part of the proprietary sensor cable...

I really think I should get Hobbywing's OTA Bluetooth module now that I think about it. I could see temps right from my phone.