Brushless Motors Failing

[Nelson.81]

A Hobbywing esc gives you thermal protection when paired with a Hobbywing motor if running it with the sensor wire. But it won’t give you thermal protection with a non HW motor only the esc has thermal protection with a non hw motor. Not sure what the temperature cutoff is though

 

[KnowAir]

I think the 2250kv from the hw 4278 is just too much kv. If nothing else the rpm it a bit excessive on 6s and combined with my lack of mechanical sympathy with running temps is why they have died.

I’ll get a sub 2000kv motor, preferably larger than the 4278 on order along with some pinions to get the wheel speed back up to mid 40 mph on 4s. In the mean time I’ll take it easy on the 2250 kv hw motor with reduced punch, smaller pinion, and shorter runs.

Then pick up an Asuga when they are back in stock to put the max8 combo into…

I would think the 4278 would be fine on 4s? Kinda what it’s really made for. It’ll handle 6s, but the kv suggests 4s is where it’s best suited. Albeit in a lightweight truggy.

 

[danl]

You bet!
https://www.ebay.com/itm/3348678166...u9b9Aq4RVDGTcTHJv1eXUSZ7Qe6ITg8Exkega1w&gQT=2
1450kv is pretty low, my plan was to use it in my Kaiju on 6s, but the Kaiju motor mount adjustment range is too small. I couldn't get satisfactory speed out of it so I scrapped the idea. Decided to try the 1450kv in my Arrma after some other failure left me needing a motor for it. Not the most powerful motor, but gets it done for me.
This would be my pick for the Kagama on the cheap..
https://www.ebay.com/itm/3345643466...5FV343&hash=item4de596cafb:g:SEgAAOSwo9divbye

I've also bought several of the Surpass motors from Amazon, including the GoolRC brand which is the same.
RC Juice has some pretty good deals right now too.
https://rcjuice.com/collections/all-around-motors

Thanks, just ordered the 4274 1750 KV. It should be a good motor to tune the setup with, to use as a spare, or to put in when the weather is hot and I just need to keep it pinned for minutes without lifting.

 

[danl]

I would think the 4278 would be fine on 4s? Kinda what it’s really made for. It’ll handle 6s, but the kv suggests 4s is where it’s best suited. Albeit in a lightweight truggy.

The HW was fine on 4 packs at 4s. Then I put it on 6s and it blew up in under 5 minutes.

 

[danl]

A Hobbywing esc gives you thermal protection when paired with a Hobbywing motor if running it with the sensor wire. But it won’t give you thermal protection with a non HW motor only the esc has thermal protection with a non hw motor. Not sure what the temperature cutoff is though

Good point. Though the HW motor never did enter a thermal protection before it blew. It is likely the Kagama LE, my driving style, and the hot summer weather did it in. That and its probably over marketed as being compatible with 1/8 monster trucks when the max6 line is what I should have bought. I just didn't know as much 2 weeks ago as I now know today.

The temperature setting enable seems to be a setting in the older app that is no longer visible to the user. They never do state what the cutoff temperatures are but I can tell you that I did not hit an ESC or motor temp limit. I went into a face of a jump full throttle and had air control, landed it, and on its way back to me it started binding up. It was on 6S at the time, decent wheel speed, and something on the inside decided it had enough, but only after the car successfully landed.

 

[Atomic Skull]

Hello,
I am new to the Corally Brand with a Kagama LE. I got about 50 runs out of the stock grizzly motor before it locked up on me. Upon inspection the front motor bearing was slightly worn but the rotor is showing some delamination and the balancing material appears to have chipped off. Also the motor vibrated the pinion loose. Upon inpsection, there was a bit of dirt in the motor.

I put a HW max8 combo in it and the motor failed on the 5th run. Again the motor locked up. I did not open it up as I intended to warranty it which I did.

So then I put in a new Kuron 825 and did 5 runs. I went to swap it into my Traxxas 6S truck and noticed when swapping over that the output shaft was binding. Upon inspection there was dirt in the motor.

I am wondering if anyone else has issues like this. I figured the first grizzly motor just had a bad part. But then when the HW motor failed so quickly I start asking what am I doing wrong? Then the Kuron 825 has loads of dirt in it.

I'm thinking that dirt is making its way in the 2 unused motor mounting holes? I have left these open as that is how they come from Corally. On the corally design the motor is in line with the front tire which can and does throw debris in its direction. The traxxas 6S truck completely seals the front of the motor. I get 100+ runs out of the traxxas before the bearings go bad.

Thoughts?

I had overheating issues with my Asuga and a Max 8 combo on 6S and a 13T pinion with both the ESC and the motor. It seems that Hobbywing run their ESCs in sensored mode full time where many others will switch to more efficient sensorless operation at higher RPMs. Disconnecting the sensor wire stopped the overheating.

I initially switched to an XC-ESC E6 and that solved the overheating problem (these are also sold as Mad Max ESCs, they are actually really good ESCs).

https://www.xc-esc.com/product-category/xc-electronic-speed-controllers-escs-for-rc-cars/
https://www.xc-esc.com/product-category/c-series-for-rc-cars/

https://mad-motor.com/collections/max-series-esc

I eventually converted it over to a full Castle system (Mamba Monster X and 1717 motor).

 

[Horatio]

The HW replacement motor arrived and it is 100% sealed. The mounting holes are blind holes. Maybe the last HW motor failed due to some defect? Motor temps never got over 190F and I run two 30mm fans on it.

The stock corally grizzly motor has open holes and it definitely ingested dirt as its unused mounting holes are through holes. I was going to put aluminum tape over the front of the motor to cover them, but filling them with grub screws is a great idea which I will do if I ever put an open motor back on it.

I'm not crazy about bout a chassis net because I want to get good airflow to the ESC, motor, and battery.

If you've just destroyed 3 motors, how are you not keen to try preventing dirt ingress with a shroud?

I've never understood that logic. 93% airflow with fans that work is 1000% better than Vs 98% airflow with fans that are on stop, with the shellac melting quietly away inside your motor. Your motors shouldn't be going over 160°F.

At 190°F you are cooking them!

Shrouds barely reduce airflow, but they keep your fans running.

If you don't run fans, you likely should be. The results so far speak for themselves, no?

In the meantime - try running lower gearing, with smaller pinions. The Grizzly may have had FOD inside of it, but it's the heat that delaminated it and screwed the bearing.

And manage the throttle on 6S. It's not really optional unless you accept continual breakages.

Good luck and let us know how your next motor fares.

 

[KnowAir]

If you've just destroyed 3 motors, how are you not keen to try preventing dirt ingress with a shroud?

I've never understood that logic. 93% airflow with fans that work is 1000% better than Vs 98% airflow with fans that are on stop, with the shellac melting quietly away inside your motor. Your motors shouldn't be going over 160°F.

At 190°F you are cooking them!

Shrouds barely reduce airflow, but they keep your fans running.

If you don't run fans, you likely should be. The results so far speak for themselves, no?

In the meantime - try running lower gearing, with smaller pinions. The Grizzly may have had FOD inside of it, but it's the heat that delaminated it and screwed the bearing.

And manage the throttle on 6S. It's not really optional unless you accept continual breakages.

Good luck and let us know how your next motor fares.

I know we’ve discussed the dust covers before and I’m a stubborn blockhead, but given the above analogy I have to admit your argument makes good sense.

 

[Horatio]

I know we’ve discussed the dust covers before and I’m a stubborn blockhead, but given the above analogy I have to admit your argument makes good sense.

I thought your argument was 'why spend $20 dollars on a dusty motors shroud, when I can just re-purpose a pair of my wife's stockings'.

 

[Horatio]

 

[danl]

Ran it last night real quick with the replacement HW motor. Again it was down 1 tooth on the pinion to 12T and dropped the punch from 5 (stock) to 3. Just dong ramp jumps and flips putzing around the motor only got up to 120F. Tonight I did 2 partial packs (about 30+ minutes) of jump session and the motor again was pretty cool, maybe 140F. I'll run it tomorrow on the big field where I can really heat it up to see how the changes work. I am only running it on 4S at this time. The motor has always had two 30 mm fans on it. I don't run my cars without motor fans.

The reason I am not crazy about chassis net is because I ran one on my Traxxas Maxx Slash and I could not keep the temps down. I stopped running the chassis net and I can still get 100+ runs out of the stock motor no problem. My fans have mesh screen over them and I brush them off between runs or halfway through a run if I'm in a bunch of debris.

 

[XashBE]

Quick question. Where are you driving? Tall grass? Maybe sand?
This would stress even the best motor very quickly.

Also to consider: the part you didn't change is the esc, right ? You changed the motors yet they keep breaking, might be an esc issue? Surely some more knowledgeable people have an idea about what could be the issue.

 

[Horatio]

Quick question. Where are you driving? Tall grass? Maybe sand?
This would stress even the best motor very quickly.

Also to consider: the part you didn't change is the esc, right ? You changed the motors yet they keep breaking, might be an esc issue? Surely some more knowledgeable people have an idea about what could be the issue.

The primary issue is the motors have been overheated until they delaminated.

The secondary issue is dirt ingress has occured.

I'm not sure what other conclusion 'more knowledgeable' people would arrive at, but my guess is that it wouldn't be far removed.

 

[Atomic Skull]

If you've just destroyed 3 motors, how are you not keen to try preventing dirt ingress with a shroud?

I've never understood that logic. 93% airflow with fans that work is 1000% better than Vs 98% airflow with fans that are on stop, with the shellac melting quietly away inside your motor. Your motors shouldn't be going over 160°F.

At 190°F you are cooking them!

Scorpion Power System motors have magnets rated to 392F and motor wire rated to 356F but that is an exception and they are very expensive high quality motors.

 

[Horatio]

Ran it last night real quick with the replacement HW motor. Again it was down 1 tooth on the pinion to 12T and dropped the punch from 5 (stock) to 3. Just dong ramp jumps and flips putzing around the motor only got up to 120F. Tonight I did 2 partial packs (about 30+ minutes) of jump session and the motor again was pretty cool, maybe 140F.

160°F is where you start thinking 'Hot'.

I'll run it tomorrow on the big field where I can really heat it up to see how the changes work. I am only running it on 4S at this time. The motor has always had two 30 mm fans on it. I don't run my cars without motor fans.

That's good to know. Were the fans blocked or stalled?

The reason I am not crazy about chassis net is because I ran one on my Traxxas Maxx Slash and I could not keep the temps down. I stopped running the chassis net and I can still get 100+ runs out of the stock motor no problem. My fans have mesh screen over them and I brush them off between runs or halfway through a run if I'm in a bunch of debris.

Whilst there must be a theoretical reduction of airflow through the chassis, it will be ever so slight.

I checked my XTR during the first few runs and this was happening:

The ESC was at risk of overheating.

The motor was breezing past 190° and I wondered if the motor was getting hot

So fans and shroud it was.

The other issue it prevents is chippings gouging away at your rotating parts.

Temps were sensible, even when gearing up for 69mph runs on 6S.

The amount of air flow can be maximised by opening the zip if necessary - the space immediately above the zip is covered with the body anyway. Obviously, It depends on what surface you're running on.

Ultimately, keeping temps down depends on several variables. Fans being operational is perhaps the main thing. However, even this won't mitigate poor throttle management, over-gearing, drivetrain bind, bearing failures, too high a punch setting, insufficient time between runs to cool down - etc etc.

It is still entirely possible that there was a bearing failure in the motor, but to have 3 different motors fail like that.... - in the balance of probability, it's an operational failing.

It might just be because you're having too much fun! That's what it was with me when I first ran the XTR with no motor fans - 'bareback' on grass with total disregard. Afterall, 190° is acceptable for a nitro engine!

Shrouds are like marmite to people. Another forum user over on Arrma managed to set fire to his on the rig. Really!

To be clear, I've never used them on anything until the XTR from about 2022 onwards. Now I use them on my Sworkz S35 T2E, mainly to protect the chassis from damage, rather than keep my sensored Castle 1515 from over heating, which it simply never does on the MMX.

As for the Kuron 825, it's a notoriously 'hot' motor. It's rapid for it's size and punching well above it's weight. But it gets hot.

For general hooning around though, a motor with more volume and torque - greater overall power - like this cheap as chips 1780 KV 4292.

This motor is much less prone to getting hot and opens up more gearing options for speed runs. It's also more useable and feels punchier for general driving.

 

[Horatio]

Scorpion Power System motors have magnets rated to 392F and motor wire rated to 356F but that is an exception and they are very expensive high quality motors.

Those are Heli motors and not applicable for car use.

That being said, if such motors have wires and magnets that can withstand such crazy high temps, this is exactly what bashers and racers alike need in our motors - right now already!!

 

[danl]

I have not failed three motors. It was the stock Grizzly motor after about 50 runs (on the stock torox 185 ESC). Then the HW motor on the 5th run when I put in the first 6s pack (HW ESC). The grizzly may have been my fault with dirt. The HW I don't know because it is 100% sealed. It got hot, but does 160F kill a front bearing in 5 runs?

I pulled the Kuron 825 to inspect after a handful or runs. It still runs fine and I am running it in my Maxx Slash right now on the stock Traxxas ESC. The Kagama now has another 4278SD motor with about 45 minutes combine backyard jump session. I'll give it the beans later today on the big field.

I am monitoring ESC and motor temps. I am logging with the HW app and I can also monitor motor temps via a temperature sensor I installed on the Kagama. My fans all have a mesh filter, including the ESC and I inspect often and clean with my battery vacuum if needed. Between runs I cool off the car with a leaf blower then let it rest while I run my second car.

 

[Horatio]

I have not failed three motors.

3 of your motors have failed. No one is saying that you failed your motors, which is far too deeply philosophical for this thread

It was the stock Grizzly motor after about 50 runs (on the stock torox 185 ESC). Then the HW motor on the 5th run when I put in the first 6s pack (HW ESC). The grizzly may have been my fault with dirt. The HW I don't know because it is 100% sealed. It got hot, but does 160F kill a front bearing in 5 runs?

I think running for 30 minutes at 160° might kill some motors in 1 run.

My 825 definitely went over 190° for a few packs and lived.

I pulled the Kuron 825 to inspect after a handful or runs. It still runs fine and I am running it in my Maxx Slash right now on the stock Traxxas ESC. The Kagama now has another 4278SD motor with about 45 minutes combine backyard jump session. I'll give it the beans later today on the big field.

Let us know how it goes. Maybe you're just the unluckiest MF on the forum!

I am monitoring ESC and motor temps. I am logging with the HW app and I can also monitor motor temps via a temperature sensor I installed on the Kagama. My fans all have a mesh filter, including the ESC and I inspect often and clean with my battery vacuum if needed. Between runs I cool off the car with a leaf blower then let it rest while I run my second car.

All good stuff that should mitigate any overheating issues.

Please let us know if there are any further motor calamities!

 

[KnowAir]

If 160F is deemed acceptable by the manufacturer it should handle 160 indefinitely? Regardless, I think most all my electric motors have seen 180 by now, some 230, Kaiju with a $40 Surpass 4068. All still going. I have two 6 pole motors, a Ten Shock 802L 4274 2200kv and a Turnigy Track Star 4268 2560kv. The 802L is nearly 15 years old, Track Star about 10. Neither has any wrap left on the rotor, the 802L just lost a bearing on the output end, upon inspection it seems the rows of magnets are no longer tight or aligned. New bearing installed, see what it does, LOL. Both have been outstanding performers for me, I might even buy anothor 802L TBH. The Turnigy motor is now obsolete, the two look identical inside and out. Bet they came from the same sweat shop!

 

[KnowAir]

Hell yeah!! Mine’s will be purple though..
(This was in response to post #30 above)