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  1. #21
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    Re: Voltage input to BLDC inverters on tethered drone?

    * As wind generator installers are aware, winds are stronger at increased altitude. A heli-craft needs to be able to counteract these effects. It must not be carried away from the tether.
    It should present minimal drag so wind gusts don't push it around as much.

    Suppose a 30 mph breeze is at tether altitude. Your craft must remain stationary which means it needs to perform the equivalent of flying level at 30 mph. It also needs to be able to stop rotating if that were to begin. There may be an advantageous to mounting one or two propellers so they blow horizontally.

    * For test flights you might wish to install on-board batteries so that an emergency landing is possible in case of tether separation.

    Quote Originally Posted by treez View Post
    13
    Consider what pattern of support you'll construct for this amount. Does it require extraordinary effort? Difficult calculations? Struts attached at peculiar angles? Etc.
    A 4x4 grid seems reasonable. That accommodates 13 motors, and gives you space at the center for a payload.



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  2. #22
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    Re: Voltage input to BLDC inverters on tethered drone?

    Thanks, wow, the BCM4414xH0E5035yzz (800V->48V, 1.5kW) costs $832 for one piece, $530 for 100 pces.
    I hadnt expected it to be that much, especially since we will have to provide the heatsinking etc aswell.
    Plus some extertnal capacitance.

    - - - Updated - - -

    And for all that money, above 70degc case temperature, the output current starts de-rating very significantly.....hmmmmmm...as page 9 shows....

    http://www.vicorpower.com/documents/...5yzz-VICOR.pdf
    Hmmmm, is it worth the money



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  3. #23
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    Re: Voltage input to BLDC inverters on tethered drone?

    I don't know - even open frame 1kw+ supplies are in the $ hundreds. With a custom development effort you could probably cut cost but doubtful you can beat Vicor on size or weight.

    With good system design you should get a ton of cooling for free in a drone..



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