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  1. #1
    RC Racer
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    Strange Motor Buzzing

    Trying to figure out what the issue is here. Once my motor warms up, if you give it very slight throttle, it goes into a “buzzing mode” where the engine buzzes and gets louder as you give it more throttle - but it doesn’t go anywhere. If I do not gently press the throttle, it does not happen.

    See video below - is this an engine issue or a common thing for the Velineon 380?

    https://i.imgur.com/PydQVon.mp4

  2. #2
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    Thats just a problem with sensors less motors. Don't lightly throttle it from a stop and it will be fine.

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  3. #3
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    Quote Originally Posted by Extremercing View Post
    Thats just a problem with sensors less motors. Don't lightly throttle it from a stop and it will be fine.

    Sent from my SM-G973U using Tapatalk
    I have never had that issue with my slash 4x4 vxl motor. I thought only cogging was a sensorless motor issue? this is like the motor isn't moving at all.

  4. #4
    RC Qualifier Sp2deSummit's Avatar
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    Not sure what that is, have you checked your slipper clutch? It may have loosened up. Or it could be a faulty motor
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  5. #5
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    Quote Originally Posted by halygon View Post
    I have never had that issue with my slash 4x4 vxl motor. I thought only cogging was a sensorless motor issue? this is like the motor isn't moving at all.
    From what I know thats the problem. Without it being sensored the motor can't adjust to overcome the static friction in the drive train. That's what I've been told.

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  6. #6
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    Quote Originally Posted by Sp2deSummit View Post
    Not sure what that is, have you checked your slipper clutch? It may have loosened up. Or it could be a faulty motor
    Definitely not slipper nor is it the gear mesh.

    Quote Originally Posted by Extremercing View Post
    From what I know thats the problem. Without it being sensored the motor can't adjust to overcome the static friction in the drive train. That's what I've been told.
    I hope that’s not the case because while I can be less gentle on the throttle, anytime I go slow for turning or reverse, there’s a chance that it happens. When it does, I have to release throttle and then throttle again.

    I just find it very odd that I haven’t seen it in other brushless motors and it only happens after the motor has warmed up.

    Maybe a trip back to the Traxxas store is needed to confirm.

  7. #7
    RC Champion zedorda's Avatar
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    At first I thought you might be having something like this happening: https://www.youtube.com/watch?v=kyV6eopQBRM
    Which is completely normal even on a sensored motor. But no yours sounds real unique, I can't say I have ever heard something quite like that. The fact that it is intermittent points to faulty.

  8. #8
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    Quote Originally Posted by halygon View Post
    Definitely not slipper nor is it the gear mesh.


    I hope that’s not the case because while I can be less gentle on the throttle, anytime I go slow for turning or reverse, there’s a chance that it happens. When it does, I have to release throttle and then throttle again.

    I just find it very odd that I haven’t seen it in other brushless motors and it only happens after the motor has warmed up.

    Maybe a trip back to the Traxxas store is needed to confirm.
    I just looked at your video. Mine makes the exact same noise. Its because its sensorless. Since every motor is different they can't and won't all make the same tones. A sensored motor will rarely buzz like the merv because a sensored motor will communicate with the ESC and the ESC will give it enough voltage and current to begin rolling. You can bring it in to see what traxxas/your hobby shop could do, but imo the only option will be changing out the motor and ESC for a sensored combo.

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  9. #9
    RC Champion zedorda's Avatar
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    Quote Originally Posted by Extremercing View Post
    I just looked at your video. Mine makes the exact same noise. Its because its sensorless. Since every motor is different they can't and won't all make the same tones. A sensored motor will rarely buzz like the merv because a sensored motor will communicate with the ESC and the ESC will give it enough voltage and current to begin rolling. You can bring it in to see what traxxas/your hobby shop could do, but imo the only option will be changing out the motor and ESC for a sensored combo.

    Sent from my SM-G973U using Tapatalk
    You know you posted the same point 3 times? Just watching the video makes it clear the sound does not happen every time and the rig does not go when it happens. What you are talking about happens every single time you hit the throttle. Not the same thing.

    You are aware that there is not a speaker in an ESC and every beep or sound you hear from it is coming from the motor, right? These sounds have nothing to do with being sensored or not. Being sensored just changes how and when you hear unintended sounds from the motor.

  10. #10
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    Quote Originally Posted by Extremercing View Post
    I just looked at your video. Mine makes the exact same noise. Its because its sensorless. Since every motor is different they can't and won't all make the same tones. A sensored motor will rarely buzz like the merv because a sensored motor will communicate with the ESC and the ESC will give it enough voltage and current to begin rolling. You can bring it in to see what traxxas/your hobby shop could do, but imo the only option will be changing out the motor and ESC for a sensored combo.
    Appreciate the input. Does your move when it makes that noise, or does it act like it is in neutral and just revving up like mine?

  11. #11
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    Quote Originally Posted by halygon View Post
    Appreciate the input. Does your move when it makes that noise, or does it act like it is in neutral and just revving up like mine?
    Rarely it will sit there and shake but most of the time its just whirring and not going anywhere. I'm heavy on the throttle so I will maybe have the stalling once or twice a run. If its doing the whirring just let off the throttle and give it a little blip to start and it will pop out of the rut. Loosening the slipper is not a good idea imo because then you have the potential to lose a lot of power in high torque situations.

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  12. #12
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    Strange Motor Buzzing

    This is for Zedorda

    A. You are being passive aggressive in an online rc forum that is designed for people to help others, not argue.

    B. I made the same point 3 times to hit home with OP that being sensorless is the problem.

    C. You clearly aren't educated in the actual functions of a sensored motor. Sensors allow for a smooth power curve from zero to full throttle. You claim to know that sensors are for controlling the sounds that come from a motor. That is semi true as the sensors help to control the powerband directly affecting the sounds. This can be used to make sound effects if you have the proper knowledge in how to take advantage of the system. Its like using old printers to play a retro song. Have an actual understanding of what you are talking about before handing out the tone of voice you were.

    D. Even if you weren't trying to sound that way, you did. Always make sure you are certain about what you will be posting and check its underlying feelings.

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  13. #13
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    Quote Originally Posted by Extremercing View Post
    Rarely it will sit there and shake but most of the time its just whirring and not going anywhere. I'm heavy on the throttle so I will maybe have the stalling once or twice a run. If its doing the whirring just let off the throttle and give it a little blip to start and it will pop out of the rut. Loosening the slipper is not a good idea imo because then you have the potential to lose a lot of power in high torque situations.
    My slipper is pretty tight and will stay that way since I have the center diff installed.

    But yeah, I have found that bliping the throttle does allow it to then catch. I fully understand what you are saying with the sensorless motor and that when the rotor is between poles, it can have a rough start till it turns enough for the esc to get it going smooth. Clearly when it happens, the rotor isn't moving at all -- and it doesn't happen when the motor is removed from the transmission.

    Thanks for all your help.

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