NEW U7 motor tmotor

Discussion in 'Cinestar 8' started by kjetil tønnesen, Nov 22, 2013.

  1. Chakradhar Raju

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    Thanks Kari for the feedback....on 490KV....any videos which you like to indicate..and thanks for the settings too..

    Cheers
     
  2. James Cole

    James Cole Member

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    I have a X8 and X4 Mega lifter with U7's, Maytech 65A ESC's modded with heatsinks and fans. The X8 is running a WKM and flys very nice at 26 lbs. The X4 is on a A2 controller. The X4 crashed yesterday and I think the problem is the U7's with the SimonK Maytech 65A-opto ESC. I have removed my FC stack and flown multiple batteries after the crash on a stock dji F550 frame/esc/motor combo and flew it incredibly hard with no issues today. Here is a video of the crash.

     
  3. Chris Newman

    Chris Newman Member

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    I've heard others with your same issue. The esc's can't take the current the u7s put out. Ive been using the castle 75a without any issues accept for heat in these warmer temps.
     
  4. Andy Johnson-Laird

    Andy Johnson-Laird Administrator
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    Chris:
    Just to clarify what you wrote -- specifically where you write "u7s put out": Are you saying that the ESC's cannot provide the current that U7's require, or is there an issue with the so-called "back current" (Back-EMF as it is sometimes called) that the motors kick back out?

    Andy.
     
  5. Chris Newman

    Chris Newman Member

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    I'm not sure whats happening Andy, just know that castles seem to be the only esc's that work with them.
     
  6. James Cole

    James Cole Member

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  7. Andy Johnson-Laird

    Andy Johnson-Laird Administrator
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    Sounds like it's losing commutation -- just not phasing the pulses to the motor correctly. If it was back-EMF it would fry the ESC I think (but I'm not sure).

    Andy.
     
  8. James Cole

    James Cole Member

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  9. Steve Maller

    Steve Maller UAV Grief Counselor

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  10. James Cole

    James Cole Member

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    Steve, I picked up 4 ESC's to test today. All Esc's never had a sync issue like with the Maytech 65A.
    Test setup is T-Motors U7 420 KV
    6S 10,000
    The stores product manager kept telling me to try the castle 35A multirotor pack with the U7's, I tried them but knew they would not work right from the start
    1. Castle Phoenix Edge lite 75A - 1 minute at 60% throttle 106f, 2 minutes 130f - these act alittle slow in response

    2. Castle Phoenix Edge HV 50A - 1 minute at 60% throttle 97f, 2 minutes 109f - these act alittle slow in response

    3. KDE UAS 55+ - 1 minute at 60% throttle 114f, 2 minutes 155f - super fast response, seem like best option so far, but I will add fans and maybe bigger heat sinks, too hot for my liking

    4. Castle multipack 35A - 1 minute 60% throttle 160f, 2 minutes 213f - right away you can tell the motors are not getting the power they need
     
  11. Steve Maller

    Steve Maller UAV Grief Counselor

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    This may be interesting to you...

     
  12. James Cole

    James Cole Member

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    Yes, I saw that, still great results with the U7 compared to any other ESC out
     
  13. Andy Johnson-Laird

    Andy Johnson-Laird Administrator
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    James, when you say "60% throttle," how are you calculating and/or determining that please? Just eyeballing stick position, or measuring pulse width of the RC signal into the ESC or using some other means?

    Andy.
     
  14. James Cole

    James Cole Member

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    Nothing scientific Andy, these were just stick positions. I will be doing more accurate tests today starting by getting out my Spock ears . I will set the throttle travel to **%of total travel for that esc, unless someone has a better way to run these tests for someone that only has so many tools in his bag.
    I chose 60% because my X8 with U7's 420Kv take off at about 47% throttle and at 60% approx throttle in manual mode the copter can really move
     
  15. Andy Johnson-Laird

    Andy Johnson-Laird Administrator
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    See your Inbox James. I'll send you a PM in a couple of minutes.
    Andy.
     
  16. James Cole

    James Cole Member

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    todays tests with KDE 55+ and T-motors U7 420Kv with SYNC ISSUES

    Had to add a 2.5cm fan to the KDE to keep the temps down around 120f

    Juicy spots are 0:14, 0:25, 3:50 is at about 50% throttle and make weird sound, 6:08,
     
  17. Loris Coniglio

    Loris Coniglio New Member

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    Hi

    Tested today my new Octo Coax
    Motor: Tmotor U7 490kv
    Prop: Xoar 17"
    Esc: Tmotor T80A 400hz

    Total weight: 13Kg

    Motor Temp after 3 min of slow flight/hovering: 37-38°C
    Esc Temp: 58-62°C
    Outdoor temp about 28°C

    How is possible Esc are at this temp. Are they safe when adding payload (I have to add about 6-7 Kg) ?
    Need bigger (!!!) or BETTER Esc?
    What is maximum temp for you?

    Thanks
    Loris
     
  18. James Cole

    James Cole Member

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    Do you have any issues with sync with these esc? have you bench tested these escs and "fluttered" the throttle to see if they loose sync? if you do not do this your copter could end up falling out of the air.

    The best way to get the temp down is to get some 2.5cm fans and add then to the esc. another way it to use thermal epoxy and a fan added to the esc


     
  19. Loris Coniglio

    Loris Coniglio New Member

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    bench test without sync failure.
    With Tmotor 4114 have this issue on Maytech simonk Esc 60A (with 50A is ok)
    This setup havent sync issue. (I choose Tmotor Esc because is the same brand of the motor and I hope they tested their combo)

    The only perplexity is for Esc temp.
    With other motor, and the same weight, smaller esc (60-65A) are cooler.

    What is the max esc temp to fly safe?
    Thanks
     
  20. James Cole

    James Cole Member

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    technically the shutdown temp is around 220f. I start to get concerned around 140f. some people are fine running 180f, i wont do it.


    did you happen to "flutter the throttle" in your tests?
     

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