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  1. P

    Samples here-Flanged GOOD Quality FW's w/dual Row Bearings

    wow, that´d be super. I want two, depending on width and number of pawls. I want as many pawls as possible.
  2. P

    Brakes on Electric MTB's - A Lesson Learned

    persoNNally, I just jump OVER whatever obstckalage is in my way, never been an issue... I have taped a squirrel to the throttle stick so it is just plugg inn the hamsters and GO....
  3. P

    Doing the Math

    what, alu inside the coils? :shock: Also, what lateral forces is it that was mentioned on the stator?
  4. P

    Re-wind of a turnigy 80/100 (Now-tutorial w/Video)

    So you're running phase change cooling (solid to liquid) - pretty advanced stuff... Cotton would prolly be ok, and glass roving. :)
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    DC to DC Converter?

    never seen a cellphone charger put out more than 0.5 A... farnell has some super expensive little bricks with such wattage. I would have run a synchronous converter current mode for the leds (its the only type ive built), from 24v, or put them in series. They don't always take well to strong...
  6. P

    Re-wind of a turnigy 80/100 (Now-tutorial w/Video)

    spectra melting yet? supposed to take 100c max.
  7. P

    Simple BLDC controller

    Thanks again, those look like the kind of papers I was looking for (but not hard enough). I did find IXYS' chip catalog, they don't list the good chips, but some of the ones they list are relatively large compared to their package. You're saying that small chips have less Rdson - that is...
  8. P

    Simple BLDC controller

    Is there space for more wires?
  9. P

    Simple BLDC controller

    Probably narrowing down a bit, but aren't these chips quite huge, covering most of the base plate? I'm not thinking about using PCB, but sandwiching a waterblock between two layers of FETs.
  10. P

    Simple BLDC controller

    Well, I want to know. Also, it matters if you want to push the FET, you need to know what is the failure point. That is why I asked about the TO legs. If the legs are a problem, pull the heat from them with fat wires close to the epoxy, or clamp them straight to the sink. Probably.
  11. P

    calculating power loss from wire resistance

    I don't know exactly. But I think maybe the formula above assumes infinite induction in the motor and infinite voltage stiffness in the supply to the FETs (caps and battery). I picture induction as a sort of flywheel, that resists change in velocity (current). If there is *no* induction in the...
  12. P

    calculating power loss from wire resistance

    from "use extra caps!" I also just read around here somewhere that phase current is (1/pwm duty cycle) * battery current. However with the induction in the motor I am not sure if it's accurate for calculating wire loss.
  13. P

    Simple BLDC controller

    I see, but that is just a "rating" right, tells me nothing about whether it is the silicon or the leads or the epoxy that can't stand it. It's still over 100 amp more at 100 deg C than 4368 at 25C. It's got a smidge lower on resistance than 4368 and is a bit larger slug area too. I've emailed to...
  14. P

    Simple BLDC controller

    I don't know what it is, but it is not the lead current limit - that is called IL and is listed along with IA in the other datasheets. Possibly avalanche current? Do the leads usually melt inside or outside the package?
  15. P

    BLDC Brain and Simple Brawn

    Awesome. Maybe you or Jeremy can post the brawn schematic again, because the one you posted in the "simple" thread is broken, after the forum upgrade. edit - thanks a lot
  16. P

    Simple BLDC controller

    Thanks - "200A".. Don't know how I missed that. On the LED's with unisolated slug it was often enough to use an anodised sink, or some nail polish, or even just sharpie pen...
  17. P

    Simple BLDC controller

    Here are some 75v FETs, package current limit for IXFZ520N075T2 isn't listed, it's got some fat leads compared to those little TO packages it seems. Are any of those IXYS better than IRFP4368? IRFP4368 MMIX1F520N075T2 IXFK520N075T2 IXFZ520N075T2 IXFN520N075T2 Jeremy, you mentioned that the...
  18. P

    Allowed HTML Tags (will have to be revised, no longer works)

    Most of the pics are broken, some have strange colors below the break too.
  19. P

    halbach arrays (was peak torque)

    Right - so the trials ratchet will wear faster. It can be bought separately at tartybikes.
  20. P

    halbach arrays (was peak torque)

    Ah, thanks. The teeth will only engage half as many times, so if fatigue has an impact at all on the strength of the pawls, it might matter. And it has more engagements too :). I stupidly thought the name "heavy duty" (HD) ment something.
  21. P

    halbach arrays (was peak torque)

    Is the heavy duty ENO more heavy duty than the green trials version (36t ratchet 3x2pawls=72 clicks)? Is the HD 1x6=36 clicks, maybe? If so, it should be stronger I think? Attached a rhino sketch. The green things are the fw's, the yellow ones are the belt pulleys. No bearings drawn and lots of...
  22. P

    halbach arrays (was peak torque)

    Herbertkabi says here that solder wick will not generate significant eddy currents. Taking a formula from wikipedia: w = pi^2 * B * d^2 * f^2 / (12 * ro * D) w is Watt per kg B is peak flux in Tesla d is diameter of wire in meters f is frequency in Hz (rpm*poles/120) ro is resistivity in Ohm-m...
  23. P

    FEMM: Modeling the 9C 2806

    I'm going to look a bit further at the model, but one thing is popping out: You are probably NOT getting 367 Nm from the motor. Radius of your wheel is about 0.33m, and 367/0.33 is more than 100kgF force, is more than 1g acceleration if your total mass is 100kg, or climb a 90 deg hill (super...
  24. P

    halbach arrays (was peak torque)

    just bought it from ebay, so it'll be a few days/weeks. Phosphor bronze sounds like a reasonable material to make pulleys out of.
  25. P

    halbach arrays (was peak torque)

    My new m8 18t 16mm pulley on its way... I think the ratings of these thing aren't making me any wiser, never seen a tensile strength number, shear stress per tooth, or what it takes to make them ratchet. This is for (A), looking for a goodyear eagle pd y45 for (B). You reckon it's some sort of...
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