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  1. #1
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    how do the brakes work?

    I am running a totally stock e-revo with stock titans. The motors seem to be getting weak and the brakes are getting weaker. Is there an adjustment or is it part of the motor?

    Thanks
    Rob

  2. #2
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    the motors lock up i think and then cuts the power to the motors
    i think you mite have to by new motors to fix the problem
    if your not breaking anything get more air

  3. #3
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    braking is actually accomplished by "reversing polarity" to the motor.

    think about it- in order to brake, youre actually putting it in reverse.

    A DC motor can run in both directions, just by reversing the polarity.
    Been there, done that.

  4. #4
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    that is what I thought. It is a direct connection between engine performance to brake performance. I think I need new motors. That sucks.

  5. #5
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    Yup. Same thing happened to my BL motor when it got too hot.
    Excessive heat will demagnetize the motors which, of course, makes them weaker in all respects and also less efficient, so they will generate more heat which compounds the issue.
    Do you think that maybe you allowed em to get too hot by running them too long or too hard, or do you try to give the system little breaks here n there?

  6. #6
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    Quote Originally Posted by larrydino
    braking is actually accomplished by "reversing polarity" to the motor.

    think about it- in order to brake, youre actually putting it in reverse.

    A DC motor can run in both directions, just by reversing the polarity.
    Close, but it is not reverse, it is applying a lot of resistance to the motor to slow it down.
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  7. #7
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    Check out the MarketPlace on this forum....lots of people selling brand new Titans as they upgrade to brushless for fairly cheap.
    Eat my road grit, liver lips! -Clark W. Griswold

  8. #8
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    I turn it on and run till the battery is dead. I thought that I bought a top of the line machine. You would think it could handle 1 set of batteries. I did get a laser temp gauge to start checking it.

  9. #9
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    Quote Originally Posted by harleyrob2000
    I turn it on and run till the battery is dead. I thought that I bought a top of the line machine. You would think it could handle 1 set of batteries. I did get a laser temp gauge to start checking it.
    Depending on the batteries you are using.. Heat may in fact be the issue..

    But also.. Are you sure the batteries weren't just getting low? Motors were getting weaker.. braking getting weaker.. Sounds sort of like the batteries were losing juice.

  10. #10
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    Quote Originally Posted by harleyrob2000
    I turn it on and run till the battery is dead. I thought that I bought a top of the line machine. You would think it could handle 1 set of batteries. I did get a laser temp gauge to start checking it.
    You did buy a top of the line machine - you still have to treat it right, though. You can't buy a Ferrari, rev it into the 9000's and then complain that you threw a rod, and that shouldn't happen on a top of the line machine. You treat them right, and either car will give you top-notch performance for a good long time. (Of course, a stock e-revo is like buying a Ferrari with 2.4L V6 under the hood... )

  11. #11
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    What batteries are you running?
    Some things are just meant to make us wonder.

  12. #12
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    You have run one pack through the truck?

  13. #13
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    Stall current?

    You're right though, it wouldnt send the motor straight into reverse though, as that would be an instantaneous halt, causing the truck to front flip, probably killing the gears in the process.
    READ THE FAQ!
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  14. #14
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    I assumed it was dynamic braking, as described here: http://www.engineersedge.com/motors/...efinitions.htm

    (A great cheat-sheet on electric motors & terms, got me up to speed quick). (pun intended)

    - Tony

  15. #15
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    Quote Originally Posted by kraegar
    I assumed it was dynamic braking, as described here: http://www.engineersedge.com/motors/...efinitions.htm

    (A great cheat-sheet on electric motors & terms, got me up to speed quick). (pun intended)

    - Tony
    Thanks for sharing that! Nice find!
    be nice.

  16. #16
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    Hmm, interesting find that.
    READ THE FAQ!
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  17. #17
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    I kept meaning to pm you about adding it to the faq, and never did. Sorry.

  18. #18
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    "how do the brakes work?"


    You could always just run it into a curb, or tree, or car if you wanna stop it...

    Drive it like you stole it.
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  19. #19
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    I assume your EVX-2 requires you to hit reverse twice before the truck will actually go backwards right? Once to brake, the second time actually makes it go backwards...

    Took a while getting used to doing that to go backwards...

    Edit: Nice motor website.
    Last edited by Spyre; 08-28-2008 at 03:45 PM.
    To write with a broken pencil is pointless.

  20. #20
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    That's why I figured it was dynamic braking. Hitting it the first time shorts it through a resister, as described in the link above. The second time actually sends a reverse charge to the motor, causing it to run backwards.

  21. #21
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    I need to add some tutorials to the FAQ, and some lists of abbreviations and terminology- think that site will go nicely with that lot.
    READ THE FAQ!
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  22. #22
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    ESC brakes a motor by turning on the FET's between the Neg battery lead and each motor leads. The will short out the motor, thus slows it down.
    See: http://www.4qdtec.com/bridge.html
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  23. #23
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    I totally agree.
    I think traxxas just bites the bullet on negative feedback about their stock motors cause they know the motors don't spend much time in the trucks. You can't ask for a more durable and reliable chassis as the revo though. I love my nitro versions and so far the electric has proven just as durable.

  24. #24
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    Just found this thread as I try to solve a problem.

    My E-Revo has not been run that much, but lately the brakes are getting really weak even with new batteries. I tried to reprogram the ESC but did nothing. The motors were just cleaned and oiled as well.

    There is a possibility that the motors might have gone into 200 degree territory at some point, but I truly doubt it.

    Is this "slow braking" a sign of a weak/damager motor?
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  25. #25
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    I wish these elctrics had mechanical breaks they are more realistic I like them more.
    Agree with slowenufs sig wheres the new 4 tec?

  26. #26
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    djbis, yes I would think your motors are on their way out. Sorry to say, but the Titans just don't last long at all. You might think about upgrading to some of the Kershaw motors, which are still a brushed motor, or look to a brushless setup. I went through a couple of sets of Titans before I got really fedd up with their poor performance and went with the Kershaw 650s. They still run hot, and are about the same performance as the Titans speed wise, but they seem to hold up longer. Next for me is brushless....
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  27. #27
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    Quote Originally Posted by Chachi_RC
    djbis, yes I would think your motors are on their way out. Sorry to say, but the Titans just don't last long at all. You might think about upgrading to some of the Kershaw motors, which are still a brushed motor, or look to a brushless setup. I went through a couple of sets of Titans before I got really fedd up with their poor performance and went with the Kershaw 650s. They still run hot, and are about the same performance as the Titans speed wise, but they seem to hold up longer. Next for me is brushless....
    Thanks Chachi. So this IS a symptom then...
    That sucks. The truck is fairly new, so I might hit up Traxxas for a replacement, because it really is kind of unreasonable.
    I remember absolutely THRASHING my original (first gen.) E-Maxx, and that thing NEVER stopped on me. Those little motors are strong!

    What happened to the new Titans? Its a real shame IMO. I have heard mixed comments from people, but more so on the negative side.

    Kershaw is next for me I guess, at least for this winter. By next summer I might invest on brushless.


    Thank you Chachi.
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  28. #28
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    The new titans have advanced timing and are 21 turns instead of 23 turns so they do not last as long. I just bought some old titans from my lhs for my e-revo. I put about 5 runs on them already and they have much more power and are faster than the new titans. They are also better overall than the single 700HO I had. I have them geared at 17/68 and they were only 110 degrees today in 74 degree temps outside. I think they will hold up great. You can buy them from towerhobbies.

    http://www3.towerhobbies.com/cgi-bin...&I=LXXF54&P=ML

  29. #29
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    Quote Originally Posted by HobbyGuy321
    The new titans have advanced timing and are 21 turns instead of 23 turns so they do not last as long. I just bought some old titans from my lhs for my e-revo. I put about 5 runs on them already and they have much more power and are faster than the new titans. They are also better overall than the single 700HO I had. I have them geared at 17/68 and they were only 110 degrees today in 74 degree temps outside. I think they will hold up great. You can buy them from towerhobbies.

    http://www3.towerhobbies.com/cgi-bin...&I=LXXF54&P=ML
    No kidding. I did not know that they were the same physical size, and I also did not know that the EVX-2 could use them without any problems...

    So good experiences all around eh?

    I might have to give this some thought. Afterall I have my old titans still on the emaxx. I did see some rust on the coils inside, does that mean they are not going to work? Or will they be ok?

    They have not been run in years.
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  30. #30
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    the titans in my old e maxx never got more than 110 degrees. if I took out the titans/evx(not waterproof) how much do you think I could get out of them both?
    Agree with slowenufs sig wheres the new 4 tec?

  31. #31
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    So far they are great. Hooking them up is simple and the evx-2 should actually handle them better than the newer titans since they draw less power. They may still work, it probably would not hurt to try. The only problem I see is that the e-revo has one reversed motor and the e-maxx does not. Motors should be broken in the direction they rotate so they run at the same speed. You could try it though.

  32. #32
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    Quote Originally Posted by HobbyGuy321
    So far they are great. Hooking them up is simple and the evx-2 should actually handle them better than the newer titans since they draw less power. They may still work, it probably would not hurt to try. The only problem I see is that the e-revo has one reversed motor and the e-maxx does not. Motors should be broken in the direction they rotate so they run at the same speed. You could try it though.
    Good point, the reverse rotation motor is probably going to create problems for me. hmmm...
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  33. #33
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    Hooking it up is easy, just connect the negative motor lead to the positive esc lead and the positive motor lead to the negative on the esc. It will work, but the regular rotation motor will have to work harder since the reversed motor was broken in in the wrong direction and will not rotate as fast. Hope this helps you out. The best thing to do would be to buy a new set and break them in in the proper direction.

    http://www3.towerhobbies.com/cgi-bin...&I=LXXF54&P=ML

    In the description it says the motors are the 23 turn old e-maxx motors.

  34. #34
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    Traxxas doesn't sell the 23T Titan anymore. The old and new Titans have the same part number. The best bet is to get the Marine Titan which is 23T or 24T with no advanced timing: http://www3.towerhobbies.com/cgi-bin...&I=LXGBG8&P=SM
    Last edited by kschauwe; 10-13-2008 at 02:53 PM.
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  35. #35
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    This is how strong a electric motor brake can be. I have a Neu 1515 brushless motor installed in my truggy and I normally have the brakes set to 25% which is plenty strong enough to stop my heavy truggy. I accidentally reset the percentage to 90% and this is what happened. I slammed on the brakes and the teeth on my hardened pinion actually ripped off. So you can have very strong braking action in a E-Revo with a decent motor that is in good shape. Just remember to start the percentage low and work your way up until you get the braking action you want.


  36. #36
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    Quote Originally Posted by shark413
    This is how strong a electric motor brake can be. I have a Neu 1515 brushless motor installed in my truggy and I normally have the brakes set to 25% which is plenty strong enough to stop my heavy truggy. I accidentally reset the percentage to 90% and this is what happened. I slammed on the brakes and the teeth on my hardened pinion actually ripped off. So you can have very strong braking action in a E-Revo with a decent motor that is in good shape. Just remember to start the percentage low and work your way up until you get the braking action you want.

    That is a failure of epic proportions!
    It sheered the teeth right off!!!
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  37. #37
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    I'd take that thing to see a dentist if I were you...
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