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  1. dirty_d

    My big(15 lb) quadcopter project

    I haven't been on this forum In a couple years but I thought I'd share a project I've been working on for a couple months. Its pretty much finished it last night and did a quick 1 or 2 second hover test in the living room :shock: here are the specs: 4x 5055 size 1600W 700kv motors 4x 60-70A...
  2. dirty_d

    anyone got pics of the inside of a kelly controller?

    im curious how they mount the mosfets in there to handle up to 200A, the biggest pain in the ass for my project for me was coming up with a way to mount the mosfets to be able to handle 100A.
  3. dirty_d

    high power/high speed BLDC controller build

    i just ordered one of those 130kV 6.5kW motors from hobbycity to replace my poor melted MY1020 motor that my brushed controller killed. i could buy a beefy R/C ESC, but i think it would be more fun and cheaper to make one. also i think most of the rc controllers use a low PWM freq like 8khz, im...
  4. dirty_d

    anyone know how many poles the 130kv HXT motor has?

    this one... http://www.hobbycity.com/hobbycity/store/uh_viewItem.asp?idProduct=5142 http://www.xyhmotor.com/en/Emp_ProductShow.asp?ArticleID=291
  5. dirty_d

    MY1020 inductance?

    does anyone have a ballpark idea of the inductance of one of the 48V 1200W MY1020 motors? just a rough estimate 100uH to 1mH?, 1mH to 100mH?
  6. dirty_d

    dirty_d's 100V 75A brushed motor controller schematic

    I figured id take on a brushed controller before i try to make a sensorless brushless one, which is about 5732 times harder. i made the schematic today, i havent finished choosing all the resistor and capacitor values yet. im not really sure how big the main caps should be, i cant remember what...
  7. dirty_d

    analog bldc zero cross detector

    i found this in an ATmel application note for sensorless bldc motor control. when i make my motor controller in going to use something like this because the ADC smaple rate on the uC is too slow for a high pole count high rpm motor. at 6000rpm on a 12 pole motor the time the unpowered phase is...
  8. dirty_d

    Controller switching losses

    Im just trying to figure out how much energy is actually wasted for a given scenario by the fet switching in the controller. and possible ways to improve it, im not 100% on this stuff just trying my best to understand. ill use an irfb4110 as an example. first off there is the gate drive loss...
  9. dirty_d

    dirty_d's 3rd build

    i just slapped all the components together with packaging tape, i really have no patience if i have all the parts on hand, the damn thing is going together one way or another so i can try it out. i made this for my wife, its got the crystalyte 409 brushed motor and a 36V 12Ah nicd pack and a 30A...
  10. dirty_d

    NASA nicd battery guidelines

    i found this just now, its all the guidelines nasa uses for nicd batteries on spacecraft like discharge charge and maintenence. http://klabs.org/DEI/References/design_guidelines/environment_series/1103.pdf
  11. dirty_d

    is chargind nicd/nimh in parallel really so bad?

    ive been thinking about this a little, ive read that at the end of charge the voltage of a nicd cells drops about 10mV, and a nimh about 2mV. take for example a 36V pack of nicd, suppose the internal resistance of each series string is 1 ohm, just a wild ass guess. and say that just before the...
  12. dirty_d

    endless sub-c nicd soldering

    i got most of the nicd cells i ordered off ebay, the same ones safe is using in his tubes, i opted to just solder them all together with the tabs. i got 110 of the 160 i ordered, not sure why i didnt get all 3 packages the same day. the first string of 30 cells was a nightmare, but after the...
  13. dirty_d

    crystalyte brushed direction of rotation

    is there a certain direction that this motor works best at? i don't see an arrow on it anywhere. one side of the motor has a crystalyte logo machined into it, facing that is it supposed to be clockwise or counterclockwise, its the same side the wire comes out of the axle on.
  14. dirty_d

    nicd pack charger(finished)

    im thinking about building a nicd pack with those cheap sub-c cells on ebay, 30s5p. i dont want to have to use 5 chargers to change the damn thing, how about this circuit, that should work right. diodes to isolate each string. each string gets charged separately. the charge current will probably...
  15. dirty_d

    BD-36 or crystalyte brushed?

    anyone have experience with both of these motors? or know a lot about both of them? like technical aspects like speed and torque, or no load speed of the BD-36(crystalyte has theirs on their site) and winding resistance. they are both the same price, so im not sure which one i should get if i...
  16. dirty_d

    how many 4 series crystalyte motors are there?

    on electricrider.com they call them sparrow and roadrunner, then they have 2 kits the 3625 and 4825 for the sparrow, im guessing that thats just difference between the controller between each kit, or are they different motors as well? in the graph they show the 3625 and 4825 are pretty much the...
  17. dirty_d

    HXT 130Kv motor sold in the USA?

    i want this motor, and i want it bad http://www.hobbycity.com/hobbycity/store/uh_viewItem.asp?idProduct=5142. i think that site is based in the uk, the shipping is about $35, i was wondering if anyone knows a place to buy from in the USA? google search hasn't shown anything. i found the company...
  18. dirty_d

    sensorless BLDC zero cross detection

    ok, so im going to start designing a sensorless brushless motor controller, but before i even start drawing any schematics im going to make sure i understand every part of its operation, so far this has been the most troublesome part. it seems there are so many different ways to do the zero...
  19. dirty_d

    BLDC controller motor current limiting

    ok, if i had a current sense resistor between GND, and Q2 in this schematic http://www.st.com/stonline/products/families/transistors/power_mosfets/related_info/images/stx5nk52zd.gif then constantly taking samples and averaging them over time would give the battery side current right? but if i...
  20. dirty_d

    effects of commutation timing

    i drew out a couple of graphs today to show how the timing advance on a 3 phase motor affects the instantaneous and average torque. and why it will increase the no-load speed. each commutation step is 60° electrical degrees, the max torque on the rotor occurs 90 electrical degrees before the...
  21. dirty_d

    electronic winding shifting

    ok heres what i came up with for a motor with 2 Kv settings. how would you do this electronically? the phases are constantly switching polarity, wouldn't that cause problems for fets?
  22. dirty_d

    rules of brushless commutation

    is there any defined set of rules or equations for the sequence the phases are to be commutated for a given pole/tooth count? for a stator with 3 teeth and 2 poles, i found the sequence i see everywhere to work, AB, AC, BC, BA, CA, CB, with the magnetic field rotating the same direction as the...
  23. dirty_d

    sensorless BLDC controller design

    if i ever make a new bike or convert the bike i have now to use an RC motor, i might just try to make a controller using an atmel avr. there were some specific brushless things im not sure about though. when you de-energize one of the coils what is done about the voltage spike? on a brushed...
  24. dirty_d

    Using RC motors on E-bikes [Archive]

    i thought this was crazy until i saw recumpent's build log of his e-bike, i did a little more research and these motors are actually pretty spectacular. i got the info for the motor he used here http://www.espritmodel.com/index.asp?PageAction=VIEWPROD&ProdID=5421. then i used that info to plot...
  25. dirty_d

    trying to make a LiPo charger/balancer

    I just got a cheap electric RC airplane a couple weeks ago and just bought a lipo pack and a cheap lipo charger, maybe too cheap. id like to make my own charger in case the other one doesn't cut it, ill learn more about electronics in the process too. i think ive gotten the current limiting...
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