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  1. #1
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    Dewalt brush problems need help!!!!!!!

    so i pulled my dewalt out out and took the brushes out and heres what i found

    i had a 17t in and it was way slower than my buddys stock summit so i put a 20t in my summit. so i could be the cause of this problem need help





    i need in put and where to get new brushes help please
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  2. #2
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    definitely got hot

  3. #3
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    so whats the fix? i was told i should be faster thanthe stock summit even with my slingers
    Traxxas summit
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  4. #4
    Marshal ksb51rl's Avatar
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    Not with a burnt motor, you won't be.
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  5. #5
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    Quote Originally Posted by ksb51rl View Post
    Not with a burnt motor, you won't be.
    is that really necessary

    looking for help on what caused the problem
    Traxxas summit
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  6. #6
    Marshal ksb51rl's Avatar
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    To reduce the heat generated by a motor, you must reduce the amp draw. There are two main ways to do this. The first is to increase the voltage going to the motor, which will reduce the amperage going to that motor. Since the Dewalt motor is already being over-volted, I don't think this is a appropriate solution. The second way is to reduce the amount of work required of the motor. This means you must gear the motor down. Quite simply with a 17-tooth pinion driving Mudslinger tires you're asking too much of the motor. Not to mention that the tug-of-war you posted about earlier probably didn't do the motor any favors. So there you have it: gearing down will reduce the heat and you won't burn the brushes.

    Now a question for you: was this a new Dewalt motor? I have never seen brushes burn that badly that quickly. And a suggestion: check the commutator for carbon buildup. That's the supposedly bright copper-colored part of the motor that the brushes contact. I would guess it has seen some wear and will need to be cleaned with a commutator cleaning pen before you replace the brushes.
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  7. #7
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    the dewalt is 2 months old.... so i should replace the brushes and put the 17t back in there ?
    and stay away from tug of war
    Traxxas summit
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  8. #8
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    From what i read the 17t is about stock with a dewalt and stock tires. i would go down a size or 2 and watch the temps on your motor. If you cannot put your hand on the motor after a pack its 2 hot. Search the forums their is some good info on dewalt and gearing

  9. #9
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    ok so my plan is new brushes run a 14t stock summit gear for brake in maybe 2 sets of packs then switch to a 16t. dose that sound good

    i will be running my slingers most of the time till i save for a set of rock rages
    Traxxas summit
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  11. #11
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    Dewalt brush problems need help!!!!!!!

    Just for info sake I run a 17T pinion with my Mudslingers all the time. I have never had a problem like that. My truck has gobs of torque and is definitely faster by a good few mph then when I was running my original Titan motor.

    Now I will also say with the Slingers, Dewalt, and a 17T and hot outside temps the motor will run on the warm side. Here in NorCal this past summer with 90 degree plus outside temps at the end of a pack I was seeing temps on my Dewalt around 170 degrees. That is pushing it. That was for an hour bash mixing in first and second gear running about 50/50. But I have a temp gun and was also constant checking temps as I run.

    Now here in the fall/winter time running the same setup I am having no temp issues. So in summary depending on your outside temps with that setup, you should be ok ( in my experience) as long as you check your temps every once in a while. Never hurts to be safe then sorry.

    But as other have suggested, if worried at all, keep gearing down till your temps are in a acceptable range no matter what motor/ESC setup your running.

    Good luck.


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    Last edited by Sactown_Summit; 01-05-2014 at 12:59 PM.

  12. #12
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    Maybe some lighter wheels would help too. Slingers are relatively heavy for driving fast.
    Brushless 19/62 SPC 8.2 It's not a Tekin or a MM

  13. #13
    RC Champion trax de max's Avatar
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    Looks to me like wrong brush holder maybe, and/or, the holder wasn't fully seated with brushes at an angle to comm.
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  14. #14
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    Those bad boys got so hot they cracked. I hope the rest of the motor is ok.

  15. #15
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    To answer your question on where to buy new ones...look up your closest factory service center at dewalt.com.

    Question...it doesn't look like you had the wires soldered to the brushes...I wonder if you had some resistance issues and subsequent heat issues because of that?
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  16. #16
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    Quote Originally Posted by Smokeman View Post
    To answer your question on where to buy new ones...look up your closest factory service center at dewalt.com.

    Question...it doesn't look like you had the wires soldered to the brushes...I wonder if you had some resistance issues and subsequent heat issues because of that?
    It looks like he was using the KD plug and play setup.. I was not a big fan of it and ended up soldering my own 10AWG wires like most.
    Also I run 14t on Slingers.. I thought that was plenty let alone 20t.
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  17. #17
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    Does he need higher "c" rated batteries? I think he is using 25c SPC 5000mah lipos. Or does that not matter? I'm not an expert just curious.

  18. #18
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    I ran the dewalt in my summit for a couple months before the brushes went. I was running the maxamps 9000mah lips and the 19t pinion recommended on kershaw designs site. Stock 68t spur. Tires were trenchers so little smaller than slingers. It ran a little hot sometimes but never failed. I popped new brushes in it last weekend and it ran fine again. However I wanted to try more power so I got the mamba monster 2 and 2200kv motor combo. The difference is night and day. Gearing is 18/68 and its insanely revo fast now. Get more runtime due to brushless being more efficient than huge brushed motor. Motor is cool to the touch after 50+ min of running. Still crawls good in low gear. Not as smooth as the dewalt or 775 were but I imagine if you put the stock 14t pinion back on that would smooth it up for people who mostly crawl with summit. Go brushless and don't look back....however if you want to stay with the dewalt check out kershaw designs. They sell the motors all prepped to drop in the truck. Also the replacement brushes.

  19. #19
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    Dewalt brush problems need help!!!!!!!

    I am not sure I understand the high resistance or low C-rating comments. How would LESS power getting to the motor cause increased heat and brush wear?

    @Sactown_Summit: you present a conundrum. Your use of the Summit is very different from the OP's, judging by the extreme wear of his brushes. Would you care to describe how you use your Summit?

    @cottoneyed joe: the sensorless brushless systems are fine for bashing and trailing but for anything close to technical crawling they are not a good choice.
    Last edited by ksb51rl; 01-05-2014 at 11:53 PM.
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  20. #20
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    Quote Originally Posted by cottoneyed joe View Post
    18/68 and its insanely revo fast now. Get more runtime due to brushless being more efficient than huge brushed motor. Motor is cool to the touch after 50+ min of running.
    'cool to the touch'?

    Where are you running your Summit? because MMM even on stock gearing tends to run hot and definitely not 'cool to the touch' 50 minutes on 18/68?... sorry you need to provide numbers and location.

    I don't want anyone mislead thinking going BL is a walk in the park. I have the MMM system on stock gearing and it runs hot. It's still within safe parameters but far from 'cool to the touch' LOL.

  21. #21
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    18/68 should not get a Mamba Monster hot except with the largest and heaviest tires.
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  22. #22
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    Quote Originally Posted by ksb51rl View Post
    I am not sure I understand the high resistance or low C-rating comments. How would LESS power getting to the motor cause increased heat and brush wear?

    @Sactown_Summit: you present a conundrum. Your use of the Summit is very different from the OP's, judging by the extreme wear of his brushes. Would you care to describe how you use your Summit?

    @cottoneyed joe: the sensorless brushless systems are fine for bashing and trailing but for anything close to technical crawling they are not a good choice.
    Good way to explain the voltage and heat. Try jumping you real cars battery with some cheap speaker wire instead of jumper cables. The wire is gonna fry. The same thing happens if you under power a motor it creates heat thus burning things out

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  23. #23
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    Don't know what to tell you I run 18/68 gearing with the narrow trenchers and the motor is cool to the touch after Im done. The 9000mah lipos I have give me 50 min bash time. More If I crawl. I haven't hit it with a temp gun but it feels "cool". Im sure that its winter and cold outside helps.

    Ksb51rl: I know the mamba isn't the smoothest of choices for tech crawling. I avoided the tekin system and other sensored because I like to run my summit in water/snow/mud. Plus If your into super tech crawling with your summit it wont be setup for brushless speed anyway. Just stay brushed drop to a 12t pinion soften up suspension.

  24. #24
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    Quote Originally Posted by ksb51rl View Post
    I am not sure I understand the high resistance or low C-rating comments. How would LESS power getting to the motor cause increased heat and brush wear?

    @Sactown_Summit: you present a conundrum. Your use of the Summit is very different from the OP's, judging by the extreme wear of his brushes. Would you care to describe how you use your Summit?

    @cottoneyed joe: the sensorless brushless systems are fine for bashing and trailing but for anything close to technical crawling they are not a good choice.

    Typical battery pack use for my Summit? Sure I can describe that.

    If I really try to be technical, consists of about 60% first gear crawling and trail running, then about 40% bashing with speed runs and hitting big jumps (see my Traxxas Summit Trail Run Vol. 3 for a perfect example of an hour long battery pack run):



    After what you see in my trail run video (and hour of driving on a spc 50C 2s lipo with Dewalt motor/17T pinion/Mudslinger tires) the motor was approximately 140 to 150 degrees. The EVX2 was approximately 125 degrees, and my Hitec single servo was about 110 degrees. Those are all typical temps for my electronics with this setup here in the winter time (about 65 degrees ambient temp).

    Now in the Summer with ambient temps about 90, the servo and EVX run about 10 to 15 degrees higher. But the Dewalt will go above 170 degrees if I don't watch it. In the Summer I usually cut off my run at around 40 minutes and let the truck cool down (I don't change my driving style).

    Hope that helps.

  25. #25
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    Quote Originally Posted by cottoneyed joe View Post
    ...I know the mamba isn't the smoothest of choices for tech crawling. I avoided the tekin system and other sensored because I like to run my summit in water/snow/mud. Plus If your into super tech crawling with your summit it wont be setup for brushless speed anyway. Just stay brushed drop to a 12t pinion soften up suspension.
    To take it one more step, for true technical crawling, you likely won't be using a Summit anyway. I agree with what you are saying, it's just that we all use our Summits for slightly different purposes. In my case, bashing typically is performed with an ERBE, so I use the Summit to hang ten off rocks overhanging rivers or run knife edges at the top of steep cliffs (when I can). I know the MMM very well, and I cannot use it for that, even geared down to 12/65. I've tried.

    @Sactown_Summit: Thanks for the video and explanation. 140F starts to be uncomfortable for my fingers, and that's where I typically shut down brushed motors. This is undoubtedly due to my early experience with brushed 540- and 550-sized motors. I won't suggest that everyone do the same, but I will guarantee that gearing for under 140F makes brushes last a lot longer.

    I'm reading here and there that brush face temperatures should be around 140F, but how or even if that correlates to motor can temps and if that can be measured by the average user is a mystery to me.
    Last edited by ksb51rl; 01-06-2014 at 01:36 PM.
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  26. #26
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    Quote Originally Posted by ksb51rl View Post
    To take it one more step, for true technical crawling, you likely won't be using a Summit anyway. I agree with what you are saying, it's just that we all use our Summits for slightly different purposes. In my case, bashing typically is performed with an ERBE, so I use the Summit to hang ten off rocks overhanging rivers or run knife edges at the top of steep cliffs (when I can). I know the MMM very well, and I cannot use it for that, even geared down to 12/65. I've tried.

    @Sactown_Summit: Thanks for the video and explanation. 140F starts to be uncomfortable for my fingers, and that's where I typically shut down brushed motors. This is undoubtedly due to my early experience with brushed 540- and 550-sized motors. I won't suggest that everyone do the same, but I will guarantee that gearing for under 140F makes brushes last a lot longer.

    I'm reading here and there that brush face temperatures should be around 140F, but how or even if that correlates to motor can temps and if that can be measured by the average user is a mystery to me.

    Yeah i agree it would be more effective to take the temp inside the can where I am sure it is warmer then what my gun reads on the outside of the motor can, but I am yet to figure out a good way to do that.

  27. #27
    RC Champion trax de max's Avatar
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    Do you guys not check the comm temps as well as the can. Do you not think the pic of the brushes that look burnt is just carbon dust.
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  28. #28
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    Quote Originally Posted by trax de max View Post
    Do you guys not check the comm temps as well as the can. Do you not think the pic of the brushes that look burnt is just carbon dust.
    I know this is an old topic, but temps are definitely important today as well. I had my DeWalt running at up to 105*C / 221*F in a hot summer day. I have sensors in my Summit, I just forgot to set the max temp alarm. The car started smelly as burn plastic but still runs today. I may have to replace brushes soon but not a big issue.

    Do you guys know if is worth investing on the Mamba Monster 2 or X over the DeWalt (torque/speed)?

    Thanks!

  29. #29
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    Quote Originally Posted by ScutuMix View Post
    ...Do you guys know if is worth investing on the Mamba Monster 2 or X over the DeWalt (torque/speed)?

    Thanks!
    I installed the X after installing and running the Dewalt for years. It is a great way to go if you can afford it.
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  30. #30
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    Quote Originally Posted by ksb51rl View Post
    I installed the X after installing and running the Dewalt for years. It is a great way to go if you can afford it.
    Good to know that the improvement is noticeably - not just in the wallet! :P
    How is the running time?
    I wish there is a side by side comparison between the famous DeWalt vs Mamba as both have lots of torque and speed over the stock. But if the difference between them doesn't really justify the $2-300 price difference maybe is worth upgrading only if money and waterproof are not really an issue...

  31. #31
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    Theres a big difference in power, speed, and run time. Brushless motors are more efficient then brushed because of the friction the brushes place on the motor. Between being more powerful and more efficient, the run times can be drastically improved in some cases. Like in a crawler, it will more then double your run times. In a basher, it'll be closer to 30 to 60 percent longer (depends on how much you pin it). And the caslte systems are waterproof, its the sensor plug that isnt. Worst case you lose the seonsor for a bit, it'll run in sensorless mode, causing no damage. A little dielectric grease in the connection prevents this. I've been getting my systems wet for years, no issues even without the grease.
    So I say get a Brushless system, its well worth the money. You'll wonder why you didn't do it sooner.

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  32. #32
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    Thanks for your reply Steve. I'll look into it as soon as my current DeWalt will die. I'm not in a big rush as winter is coming soon and the current fall/wet season keeps me indoor for most of the time around my 1:24 scale rc I have.

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