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NEW U7 motor tmotor

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

  1. Yann Kibongui

    Yann Kibongui New Member

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    Hi Fabien, I really don't have heat issues with triple 17 inches props and xrotor pro 80A esc's, but well, maybe I'll try some triple 16x5 inches props to test it.
     
  2. Fabien Deregel

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    Hi Yann,

    most problems occur with the T motor ESC's ( they heat up pretty quick) and may people mount them under the props on coaxial setups ( one each side of the boom between the 2 motors), ut the capacitors heat up a lot with long wires. Adding extra capacitors helps a lot, but on the Tmotor 80 A esc ( standard ones) most 490 kv + 17 or 18 inches have a tendency to heat up ( less on 17, but 16 inches with habit more pitch seems to work pretty well also).
    Then, all depends of the payload and TOW of course ,
    best regards,
    Fabien
     
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  3. Yann Kibongui

    Yann Kibongui New Member

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    This is exactly what I planned to do first to avoid inductance, I bought capacitors to put esc between props, but I have to buy some 63v capacitors now.
    My main problem with T80A was not the heat but sync issues, with or without props, so I think using 16",17" or 18" would be the same.
    The fact is that Xrotor pro 80A HV are really cooler than t80A even on triple 17" for up to 6kg thrust because they have built in heatsink, and I have not sync issues.
    Good thing is that triple blade reduce noise, vibrations, perfect video, no matter the loose of efficiency, I'll build a U8 multirotor for that.
     
  4. Fabien Deregel

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    HI,

    we worked around the famous U7 490 KV on our Zenon MKIII ESC, problem solved i think (see video below) :))))
    But i get totaly different values than the ones given by Tiger Motor ( i know we are more efficient but that much, i restarted the tests all afternoon ???) , do you have any current / RPM measurement from your tests eventually to share ? I need to put muy hands on a Flame 80 ESC to check this out,
    thanks,
    Fabien

     
  5. Yann Kibongui

    Yann Kibongui New Member

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    Mais c'est géniaaaaal !
    I finally bought a herkules board for my project, and I'm really happy with it ! But your esc seems to be really interesting ! Does it have telemetry ? What is the price ? Where can we buy it ? We need infooooooos !
     
  6. Fabien Deregel

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    Hi Yann, this is a Freely Forum so i will not put too much informations here, i just wanted to show that the U7 can give much more than what people think with much more efficiency, shall you have THE right ESC :)
    All i will say is that it has everything needed and much more, and is rated 2KW but we pushed it much higher with no problems on EV vehicles ( real boats / bikes and other funny stuffs). But 2KW of true power, so you can drive a 3/ 5 KW rated motor ( even 6) at it's full potential where you would need a 250 / 300A ESC able normally :). There is 20 years of development for the algorithm and it was needed to wait the hardware that could support it which is available since just a few months..)
    For any other questions, please contact me either by email or MP, i do not want to use the FreeFly forum for any commercial infos, as i said i like to share technical stuffs but for anything else it would not be professional at all to use FreeFly dedicated forum.
    Thanks,
    Fabien
     
  7. Jay Pearl

    Jay Pearl New Member

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    Hi Guys, anyone tried use BLheli instead of simonK firmware? Is it making any difference with timing issues?
     
  8. Fabien Deregel

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    Hi Jay,

    BL Heli has a new firmware " S" using hardware PWM control rather than software ( needed when using "limitedl" microrpocessors), enabling them to go up to 36 kHz. Perfect for small FPV copters, but should be tested under load on bigger motors especialy for re synchronisation.

    For details on the Zenon / C-1 , check your private messages tonight, here is the latest tests i made with big boy motor ( we also rock a Turnigy Rotomaw 150 on the bench) but it was more funny with the Scorpion 4525, here are details of variable PWM and Phase. I did not notice better performances when going over 48 kHz on that motor for high PWM value. As usual the funny instant reverse, god i love that thing, we are going to try 4D flying on a 60 inches Extreme Flight Extra 300 ( with adding some kind of swashpate on the motor as with reverse thrust you have no control on aileron / elevator / rudder when plane is in static).



    BEst regards,
    Fabien
     
  9. Jay Pearl

    Jay Pearl New Member

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    Thanks Fabien, I am looking to hear from you.
    I've done some testing on maytech 85A HS with Blheli older firmware.Looks ok, no desync but after some bench testing I have some strange issue, throttle stick back to zero and motor still on low idle.Take a minute to stopped.The other issue was hot esc.After 7 minutes of testing motor was 45 C and ESC reached 70-80C on average 40-50amps current.I am blaming maytech for poor heatsink attachment to mosfets.Check picture, heatsink just come off! there is no thermo paste between heatsink and mosfets.This might be the problem.
     

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  10. Jay Pearl

    Jay Pearl New Member

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    Yann I've seen you testing and flying u7 kv490 with triple 17inch props ( dji 1760? ) How do you finding this setup? How much amps you have during the tests? I am reaching over 50A @ 100 % throttle with triple 15 inch and max amps for tmotor 490kv are like 44Amps continuous
    Are you limiting current draw by some throttle curves or something like that? or just exceeding specs?
     
  11. Fabien Deregel

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    Hi,
    I guess there is a heatschrink around the ESC from maytech. Thermal pads if good uality should be allright,and if there is heatschrink to keep the disspator fitted on the mosfet with good contact on the thermal pads but heatsink can not dissipate more heat than it's abilities and if it is stuck under heatshchrink without at least a hole to let the heatsink " breathe" then it will not be able to dissipate a lot at all...
    You can switch the thermal pads for dual component thermal epoxy or with K4 or K5 pro thermal paste but with the K4 /K5 you will still need to secure the heatsink on the ESC.
    ESC's like Maytech with or without Bl Heli software suffer like most ESC's from energy lost in the PWM switching cycle qhich can lead to high energy to be dissipated in the heatsink. Do not hesitate to get bigger heatsink ( available on radiospare) and put them in a god air flow, things should get much better :)
    Regarding the ESC staying at idle, could be a small throttle calibration issue, either from your transmitter or servo tester box, maybe try to redo the throttle calibration with a bit of throttle trim forward and then once calibration is done, bring back the throttle trim to neutral. If will give a bit lower pulse for the zero throttle than the one stored in the ESC if the problem comes from here and help solve your problem,
    For your other questions, check your PM ... ;)
    Best regards,
    Fabien
     

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