motor gets too hot to touch and stalls

[Fordx4Ranger]

the motor in my axial gets too hot and stalls out after about ten minutes of driving. last night at my lhs we cleaned it and swapped brushes from a different motor. but it still got hot.
i am running an FXR and noticed on friday that one of the capacitor leads had broke off. i soldered it back on. but would this be the cause of over heat on the motor?
my axial doesnt seem to have any binding. i have tried a 17, 15, and 14 tooth pinion but the motor still overheats.
i have tried 2 different motors and they both overheat.
here are the specs on the rig.
integy v11 45t motor w/ 15 tooth pinion
underdrive rear diff gears
fxr
cc bec
3pmx
running 3s tenergy lipos 1350mah 20c...... could this be the problem??
3racing dig
rovers
swx chassie

i cant figure out what my problem is. it sucks going somewhere to crawl only to get 5 minutes of run time and an hour of messing with it.
any help would be appreciated.

 

[mysharona]

Was it overheating before you had it cleaned? did they cut the com (does it need it)? when they took it apart did they put the fiberglass washer back in against the comm? Did they accidently screw up the timing when putting the endbell back on? Does this hobby sop know what they're doing when it comes to rebuilding motors? (most don't)

 

[Fordx4Ranger]

didnt take the end bell off as he didnt have a lathe to cut the comm. we did take the brushes out and they were black. we cleaned them up with light sand paper. it fixed the problem for about 3 minutes than it stalled out again. we swapped brushes with another motor and it lasted about 10 minutes than overheated again. i might go by another shop today and see about getting some new brushes and heavier springs.
what does one recomend for brushes and springs? ive heard purple springs. but which brushes. or will any do.
also would the capacitor not being hooked up to the fxr for a few runs be the problem? i have re soldered it back on but the motor is still over heating

 

[southernextreme]

sounds like the lipo w/ 20c con and 30c burst may be too much for that motor, 20c has a rating of (i may be wrong) around 27Amps

motor is rated up to 12v and can be used w/ 12v power supply to be used in a lathe, but MOST 12v power supply's are rated at 1 amp up too approx 11.5 amp

you lipo spec is suppling more than double the amps of most power supplies that are used with most lathes(which is what motor was designed for...
in turn high amps and long run time produces alot of heat...
hope this helps

 

[rmdesignworks]

sounds like the comm is glazed,,especially if your brashes were black,,thats arcing...you need to remove the armature and turn it,,you can turn it in a Dremel,,high rpm's with some very fine sandpapar and very lightly apply the sand paper to the comm until its shines

 

[madmax22]

sounds like the comm is glazed

+1 I would cut it up.

 

[southernextreme]

sounds like the comm is glazed,,especially if your brashes were black,,thats arcing...you need to remove the armature and turn it,,you can turn it in a Dremel,,high rpm's with some very fine sandpapar and very lightly apply the sand paper to the comm until its shines

+1 on glazing,
I do think it all started with the amperage from the lipo
I have integy 55t on 7.2v 3300Mah and have run motor over 1yr with org brushes and it never gets soo hot you cannot hold it.

 

[rmdesignworks]

+1 on glazing,
I do think it all started with the amperage from the lipo
I have integy 55t on 7.2v 3300Mah and have run motor over 1yr with org brushes and it never gets soo hot you cannot hold it.

Well Ive been running the same two 55's (now 45t's) on 7.2 nimh's then 20c lipos and havent had the problem of over heating..so I usually look at the comm,,

if the brushes were black that means carbon which means arcing ,,so new brushes are just passing cleaner current throught the same dirty glazed comm,,,same available current flowing irradically though the glazing breaks in the comm surface will create a lot of theat

 

[Reflection]

sounds like the lipo w/ 20c con and 30c burst may be too much for that motor, 20c has a rating of (i may be wrong) around 27Amps

I'm not sure I agree with that. I've been running 3 cells with a 25C (55.0A) continuous, 50C (110.0A) burst for the last 2 years on several different motors. From 35 and 45t handwounds,the cheapy 35t-45t Integy's on up to pullers and big outrunners. Only motor that got hot was a 5t puller,but it was on almost twice the voltage that is recommended.:lol:


What about gear mesh? If gear mesh is to tight,it'll cause heat. A 45t with stock gearing (14t pinion),should stay cool as a cucumber on a 3 cell. The tallers gears might cause a little more heat,in no way will it be to much heat though.

 

[Fordx4Ranger]

i got new brushes and some stiffer springs today. i havent changed them out yet. i will have to take the motor appart and see about polishing up the comm. my gear mesh was a little tight so when i put it back together ill set it up so its not as tight. ill let you guys know what i find out

 

[Fordx4Ranger]

so i just took my motor apart, polished up the comm, and put it back together. i also put new brushes (trinity 4380) and purple trinity springs (trinity4396). the brushes slide in and out and move freely. i put the motor back in my rig and set the pinion/ spur gear mesh.
i ran it around my living room for about 10 minutes and the motor is still getting hot. its like nothing has changed. one thing. sometimes the motor stalls and if you just touch the wire sticking out of the brush it brings the motor back to life.
i know a lot of people on here are running a fxr with the v11 motors and 3 cell lipos.
is my motor trashed? is my fxr to blame?

 

[RaleighRCer]

If the chrome "guide" is still in the brush slot, grab the tab that sticks out and pull it out. The v11's have a tendency to hang brushes on the "guide". My motors run much better this way.

 

[Reflection]

one thing. sometimes the motor stalls and if you just touch the wire sticking out of the brush it brings the motor back to life.

That sounds like a stuck or wore out brush more than anything. My cheapy Integy 35t's are bad for doing that. Mainly wearing out in my case. About every 2-3 months,it needs brushes in the front motor,4-5 months in the rear. Since your brushes are new,it's not the wear problems.

i know a lot of people on here are running a fxr with the v11 motors and 3 cell lipos.
is my motor trashed? is my fxr to blame?

I'd rule out the FXR completely."thumbsup"

Something you may try,it may have been already suggested....might try breaking the motor in. I know you've run it already,but it might help. I'm not one to break in a motor,I just hook them up and go. Some guys swear by breaking them in though,it can help. One way I've seen guys break a motor in,is to put a deans connector on your motor leads. Hook a battery to it directly and while it's running,dip it in a glass of clean water for a few. Breaking the motor in will help the brushes seat up to the comm better,that seams to be where the problem is. Couldn't hurt to try it anyway.

 

[rmdesignworks]

when i break in a motor i hook the motor shaft in my dremel and let it run for a bout 15 minutes and cut the brushes and comm. the new brushes arent timed brushes are they? youmight take the brushes out and coat the top-sides-bottom with a little dielectric grease tomake sure they dont stick in the hoods

 

[Fordx4Ranger]

ill try taking out those chrome guides. ill have to see if i have and dielectric grease in my tool box and do that while im at it.

now next thing is could this be why the motor gets too hot to touch?

 

[canibalpenguin]

It still sounds like drivetrain binding, i don't think that the batt would be the cause. Even though the batt is spec'd out to supply way more amps than the motor could handle the motor would only draw as much as it needs. After replacing the brushes and cleaning the comm it's still over heating and you know there is no binding then my guess would be that the windings are damaged. if the motor got hot enough it could have melted the coating on the wire and cause the windings to short. I would suggest taking the motor out and hook it up to a different esc/batt combo and see if it still overheats and while you have the motor out roll the truck around to see if you feel any resistance.

 

[Fordx4Ranger]

i couldnt find any binding in my rig. i went out crawling today and since i took them little sleeves out the motor does not stall out or die for no reason so that problem is fixed.
after about 15 minutes the motor starts to get hot and i stopped befor it got to hot and let it cool down a bit before i started again.
i was talking to one of the guys up at mt lhs and he recomended trying a 12 tooth pinion gear. i put it in when i got home and i can tell i lost a little wheel speed but gained some torgue.
i am going to a comp tomorrow so i will see how it does. if anything at least i know i can get through a 6 minute corse and have time to let it sit and cool down befor the lext run.
i hope the smaller pinion helps out.



what is everyone running for a pinion on their axials with a 3s lipo??

 

[Fordx4Ranger]

i drove it for a few hours today and i can say the 12 tooth pinion gives a lot more torgue. i can bog it down reall good and get 2 of the tires wrapped around rocks and it doesnt stall like it used to. wheel speed is a little slower but still has punch when needed so i am happy with it.
the motor still gets hot but can go about 20-25 minutes before it gets too hot to touch and eventually stalls out and looses power. i am guessing the temp thing is something you have to deal with running 3s lipos.
after christmas i plan on buying a good handwound motor like a warrior or even thinkin about a puller motor.

 

[rmdesignworks]

you need to get the issues causing the motor you have now to heat up solved before you go to a better motor,,solve them now then you wont have an issue with a better motor

 

[Fordx4Ranger]

thats just it. i have to found anything else. it diesnt seem to be binding anywhere. i might just take the axles and tranny and dig apart and re grease them all. thats about the only thing i have not tried.
what is a good grease that i could find localy?