RCU Forums

RCU Forums (https://www.rcuniverse.com/forum/)
-   RC Electric Off-Road Trucks, Buggies, Truggies and more (https://www.rcuniverse.com/forum/rc-electric-off-road-trucks-buggies-truggies-more-147/)
-   -   Motor Fried, Why? (https://www.rcuniverse.com/forum/rc-electric-off-road-trucks-buggies-truggies-more-147/11630539-motor-fried-why.html)

David87965 06-25-2016 01:16 AM

Motor Fried, Why?
 
Hey guys,

I have a 1/8 Trophy Truggy Flux that has Castle 1515 2200kV on 6S. It has 13t pinion and 50t spur gear and it was running fine on stock tyres but then i change tyres to Proline badlands 3.8 and the motor temp measured 160c literally. The motor is now fried so i need to find out why it fried before i buy a new motor. Would a simple change in tyres cause the temps to go ballistic? This was the very first run on badlands so they were extremely grippy. Everything else was running OK except the ESC was running a little high but it has temp cut-off and it got to 110c spike with 90-100c average. I usually get under 90c on stock tyres. Only thing i can think of is that i may have damaged the motor on the very first 6s run which was because i had too high pinion and it got really hot but it was fine for few runs after so i have no idea.

EXT2Rob 06-25-2016 07:30 AM

160 degrees CENTIGRADE??! That is way, way over temp. It shouldn't get over 160 Fahrenheit. Going to a taller tire is like gearing up. So certainly that can increase temps. Properly geared, a motor and ESC should run in the 125-140F range.

David87965 06-25-2016 07:49 AM


Originally Posted by EXT2Rob (Post 12228016)
160 degrees CENTIGRADE??! That is way, way over temp. It shouldn't get over 160 Fahrenheit. Going to a taller tire is like gearing up. So certainly that can increase temps. Properly geared, a motor and ESC should run in the 125-140F range.

Yep, All my posts are metric units unless stated otherwise. So what do i need to do? My ratios for my drive-train are 43t ring gear, 10t diff pinion with 13/50 gearing. Is this setup wrong or something? My ESC has data logging for ESC only and i get around 70C average with 90C spikes, Motor temp would be higher. Hmmmm

EXT2Rob 06-25-2016 08:25 AM

That ESC temperature isn't bad. About right. But 160C for the motor is too high. I'm not familiar with your vehicle, but as long as you're running the stock gearing, you have a known starting point. As I said, a taller tire is like gearing up, so you may have to compensate by changing the pinion to one with one or two fewer teeth. Bearings need checking. One seized bearing can raise temps ten degrees. What is your ambient temperature?

David87965 06-25-2016 08:47 AM


Originally Posted by EXT2Rob (Post 12228042)
That ESC temperature isn't bad. About right. But 160C for the motor is too high. I'm not familiar with your vehicle, but as long as you're running the stock gearing, you have a known starting point. As I said, a taller tire is like gearing up, so you may have to compensate by changing the pinion to one with one or two fewer teeth. Bearings need checking. One seized bearing can raise temps ten degrees. What is your ambient temperature?

Stock gearing for 4S is 15/50 but i moved to 13/50 for 6S and the weather was only 15C, I am going to check bearings in the morning. I will also buy smaller pinion even though 13 is tiny as it is lol.

mrbuggy1987 06-25-2016 09:16 AM

the only things I can thing of are drag somewhere, or with the bigger gripper tires it was pulling to many amps

EXT2Rob 06-25-2016 09:43 AM

Also, check your mesh of the pinion and spur gear. If it's too tight, that can cause strain on the front motor bearing, and also heat up the motor. The proper way to set mesh is the paper method. Place a piece of 20# bond paper between the pinion and spur. Mesh the gears and tighten the mount screws. Remove the paper. Mesh is now set.

David87965 06-25-2016 09:50 AM


Originally Posted by mrbuggy1987 (Post 12228052)
the only things I can thing of are drag somewhere, or with the bigger gripper tires it was pulling to many amps

ESC logs says it sent 18A average when it fried but other logs before the change of tyres ran up to 32A average. i was extremely hard on the car with stock tyres and never had this 160C problem. It is pretty weird, UNLESS the motor being driven to 90C for 10 or less times finally damaged it overtime


Originally Posted by EXT2Rob (Post 12228058)
Also, check your mesh of the pinion and spur gear. If it's too tight, that can cause strain on the front motor bearing, and also heat up the motor. The proper way to set mesh is the paper method. Place a piece of 20# bond paper between the pinion and spur. Mesh the gears and tighten the mount screws. Remove the paper. Mesh is now set.

That is possible since i like my gear mesh to be tighter than average. I am going to bed so any replies wont be read for 8 hours. thanks for responding!

David87965 06-26-2016 04:53 AM

I been studying the data logs and i have noticed the rate of temp increase on the ESC is the same for the third run which i had zero problems and the run that fried so this means my setup was never the correct setup so i conclude it came down to my hard driving and barely any resting stops although the difference between my other runs and the last runs was i did have a rest after 5 minutes which is why it took about 5 runs to finally cook it because sometimes i would stop but on my 6th run i never did. Why didn't i pick this up when measuring? because by time i took the shell off it would have dropped heaps because the weather is very cold here and would not take long at all to cool to safer levels.

tldr; too much hard brutal driving and not enough cool-down time cooked my motor.

EXT2Rob 06-26-2016 06:59 AM

Bummer dude. Looks like you may need to get a telemetry set up to monitor your motor temps in real time, if that's the case. As you found out, logs are too late.

David87965 06-26-2016 09:13 AM


Originally Posted by EXT2Rob (Post 12228272)
Bummer dude. Looks like you may need to get a telemetry set up to monitor your motor temps in real time, if that's the case. As you found out, logs are too late.

yeah, do you know any better motors for my trophy, i want it to be fast (85 km/h min) and not have to cool down until the battery goes flat... or am i dreaming lol has to be 25mm mounting holes or come with trophy motor mountable plate.

Maj_Overdrive 06-26-2016 05:12 PM

I ran the gear calc on your combo, even on 6s that's about 60mph theoretical. You want 85kph or 50mph which it shouldn't have had any problem doing and it really shouldn't have gotten all that hot either. I've run that motor in other truggies geared for about 55mph and maybe it would hit 180F when beating on it hard in really tall grass. There's no reason the 1515 shouldn't have been able to handle this combo, if anything maybe it could've used a heatsink and fan. But if you want a more powerful motor it needs to be bigger, either larger diameter and/or longer. In 40-42mm diameter have a look at Neu 1521 or 1527, Poseidon's 1527, Track Power 4070 (NOT Turnigy Track Star), or Leopard's 4085 and 4092. All are 25mm mounting. There's also the Castle/Traxxas 1717 from the XO1, but it's just under 50mm diameter requiring the center diff to be raised with a spacer.

The only time I've ever seen temps anywhere near yours was an old 2pole Feigao I overheated a bunch of times. Then I purposely way way way overgeared it and proceeded to thrash it for scientific purposes but never saw anything over 275F.

David87965 06-26-2016 10:57 PM


Originally Posted by Maj_Overdrive (Post 12228409)
I ran the gear calc on your combo, even on 6s that's about 60mph theoretical. You want 85kph or 50mph which it shouldn't have had any problem doing and it really shouldn't have gotten all that hot either. I've run that motor in other truggies geared for about 55mph and maybe it would hit 180F when beating on it hard in really tall grass. There's no reason the 1515 shouldn't have been able to handle this combo, if anything maybe it could've used a heatsink and fan. But if you want a more powerful motor it needs to be bigger, either larger diameter and/or longer. In 40-42mm diameter have a look at Neu 1521 or 1527, Poseidon's 1527, Track Power 4070 (NOT Turnigy Track Star), or Leopard's 4085 and 4092. All are 25mm mounting. There's also the Castle/Traxxas 1717 from the XO1, but it's just under 50mm diameter requiring the center diff to be raised with a spacer.

The only time I've ever seen temps anywhere near yours was an old 2pole Feigao I overheated a bunch of times. Then I purposely way way way overgeared it and proceeded to thrash it for scientific purposes but never saw anything over 275F.

Does dry dust/dirt cook motors? I kicked up alot of dust with the car, Only difference of between the runs that were normal and the really abnormally high temps.

Does this graph look right? http://imgur.com/NJYPSGp and http://imgur.com/Y0oEStx

First 3 thick vertical red lines are just "Motor start failure" warnings and the last one is just a "Normal Boot-Up Sequence" that is when i stopped and noticed the 160c degree motor temp. The horizontal pink thick line says "Temperature Cut-off 115.00 Degrees" and the thick red horizontal line is the LVC which is set for 3.4.

I am just so puzzled why this setup even blew up my motor.

Maj_Overdrive 06-27-2016 11:22 AM

What do you have the timing set at? If you got it cranked up that will heat things up.

Edit: The only effect dust will have is on the bearings. Dusty conditions with the decreased traction that comes with it will provide less of a load on the motor. The only time this isn't true is if you've got the throttle pinned, doing donuts and the like with the tires looking like pizza cutters, for extended periods of time. That's a pretty high load, high rpm situation with very little airflow. It may be fun but also something that should be enjoyed in shorter bursts.

Anyway the the rotor is definitely toast after getting that hot, it loses magnetism after getting that hot and will only overheat even easier next time it's ran. The bearings are also a pain to replace in these motors. But the windings are probably ok. The solution is simple though, get a rebuild kit. It includes a new rotor and both end caps with new bearings installed for easy replacement. Make sure the timing is set to default (I'm unsure of exact value) and try again. Or get a big boy motor.

David87965 06-28-2016 06:28 AM


Originally Posted by Maj_Overdrive (Post 12228693)
What do you have the timing set at? If you got it cranked up that will heat things up.

Edit: The only effect dust will have is on the bearings. Dusty conditions with the decreased traction that comes with it will provide less of a load on the motor. The only time this isn't true is if you've got the throttle pinned, doing donuts and the like with the tires looking like pizza cutters, for extended periods of time. That's a pretty high load, high rpm situation with very little airflow. It may be fun but also something that should be enjoyed in shorter bursts.

Anyway the the rotor is definitely toast after getting that hot, it loses magnetism after getting that hot and will only overheat even easier next time it's ran. The bearings are also a pain to replace in these motors. But the windings are probably ok. The solution is simple though, get a rebuild kit. It includes a new rotor and both end caps with new bearings installed for easy replacement. Make sure the timing is set to default (I'm unsure of exact value) and try again. Or get a big boy motor.

Timing was set to default which is "Average/Normal", there is a lower timing option too. I did not change the timing at all. I guess i was just too hard on the motor because i did abuse it by doing 5 seconds plus on the throttle and i did do lot of donuts and the like. i didn't realize it would be so sensitive. I already got a new motor coming, same motor but this time i am gonna put some vents in the shell and have best airflow set up and keep an eye on the temps very closely. I would have bought a castle 1521 from castle but the shipping is $115 AUD lmao.

Thanks everyone for the useful replies, Highly appreciated :D


All times are GMT -8. The time now is 05:55 AM.


Copyright 2018 MH Sub I, LLC dba Internet Brands. All rights reserved. Use of this site indicates your consent to the Terms of Use.