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ELEV-8 lazy motor — Parallax Forums

ELEV-8 lazy motor

icosmos72icosmos72 Posts: 5
edited 2013-06-20 15:36 in Robotics
Apologies if I'm posting this in the wrong place...

My ELEV-8 has a stubbornly lazy motor. No matter what I do, three rotors start up right away, and the remaining (right-rear) rotor stays still. After revving up the good three --- not a lot of throttle movement, but a very audible increase in speed --- the final one finally starts up. As a result, it does not take off correctly, but tries to skid in the direction of the slow rotor.

I have tried:

- Trimming --- no evident effect.
- Re-set ESC throttle range (three times) --- no effect.
- Re-set ESC configuration (twice) --- no effect.
- Move ESC to different Hoverfly output port --- problem stays with ESC/rotor.
- Problem ESC does vs. does not supply power to Hoverfly --- no effect.
- Artificial horizon on software tool --- correctly shows level when level, tilt when tilt.

Any thoughts or suggestions? The above was absolutely everything I could think of.

Thanks!

Comments

  • mindrobotsmindrobots Posts: 6,506
    edited 2013-01-04 10:28
    Does the lazy motor spin as freely as the others without power? If you spin it by hand, does it feel the same as the others?

    Welcome to the forums, there are a bunch of folks with ELEV-8s that will stumble on your question and offer help.

    I have one but it is STILL awaiting assembly on my workbench.
  • icosmos72icosmos72 Posts: 5
    edited 2013-01-04 10:44
    Ooh, good thought. But sadly the motor turns the same as the others.

    Given that, plus these efforts poking at it, I'm pretty convinced it's the ESC. But I don't know if it's the ESC doing something _wrong_, or something correctable. I recalibrated the throttle range three times for exactly that reason. Dang!

    Thanks again for the idea, it was a smart thing to try.
  • Ken GraceyKen Gracey Posts: 7,392
    edited 2013-01-04 12:16
    I'm willing to send you a replacement motor and ESC to try.

    Just PM me your shipping information.
  • garyggaryg Posts: 420
    edited 2013-01-04 20:31
    Is it possible to connect the apparent misbehaving motor to a different ESC to see if the Lazy motor performs better?
    I've been wanting to get an ELEV-8 and keep reading these threads.
    I get closer to getting one each day.

    I hope my 2 cents worth helps you in diagnosing your difficulty.
  • icosmos72icosmos72 Posts: 5
    edited 2013-01-05 09:54
    garyg: good thought and I keep being tempted ... but I worked so hard securing all those cables! :) But you're right, that's the correct next diagnosis step. I bet the problem will travel with the ESC, but betting does not an experiment make.

    In terms of edging you closer to the purchase: I found the general build process fairly straightforward, and rewarding; though I did have a bit of trouble because I received the new powerful motors (yay!) but the mounting screws and instructions for the old motors (aww). Even that, though, wasn't too bad, because everyone who had these kinds of issues got very VERY quick and personal response from Parallax, as you can see here from Ken's response. (I stubbornly decided to deal with it myself, though, by buying a smattering of screw types from McMaster-Carr and seeing which ones satisfied me best. Again: a rewarding build experience, trying things out.) In short: what came in the box was very good, and anything that wasn't good, Parallax pounces on.

    Ken: thanks very much, sir, will get you shipping information shortly!
  • ercoerco Posts: 20,256
    edited 2013-01-05 12:24
    Lazy is a strong word. Maybe your motor is differently enabled/motivated.
  • mindrobotsmindrobots Posts: 6,506
    edited 2013-01-05 13:30
    It may be more correct to get the other three motors to play down to the level of the challenged motor rather than stigmatize the differently enabled motor. With an approach like that, there may be government funding for you ELEV-8!
  • ercoerco Posts: 20,256
    edited 2013-01-05 16:08
    No motor left behind...
  • Ken GraceyKen Gracey Posts: 7,392
    edited 2013-01-05 22:10
    icosmos72's motor/esc problem has been taken care of by means of a shipment on Monday morning. Sometimes these China parts can be a bit variable in quality. I've found that the larger quadcopters are have more reliable motors and ESCs, at least in my experience.

    Let's get this ELEV-8 up in the air, pronto!
  • ercoerco Posts: 20,256
    edited 2013-01-05 22:31
    Ken Gracey wrote: »
    Sometimes these China parts can be a bit variable in quality.

    "Differently qualified!"

    As usual, Ken resolves any issue with a generous wave of his hand. I should have written you in on my November ballot.
  • mindrobotsmindrobots Posts: 6,506
    edited 2013-01-06 01:29
    I should have written you in on my November ballot.

    While the country would have benefitted, Ken deserves far better than that!! :0)
  • icosmos72icosmos72 Posts: 5
    edited 2013-01-15 13:53
    Sorry for the long delay, gang, I plead family and flu ... and also that this was a somewhat more interesting problem than it appeared.

    First off and most importantly, thank you to Ken and his team for the extremely prompt shipping of replacement parts. It was thoroughly impressive and genuinely appreciated and anyone like gary8 who's using these threads to make purchase decisions, please know that Parallax gets five-stars.

    With some irony to mindrobots, it really does look like I had three funny ESCs that made the fourth look bad. I can take everyone down the twisting path of everything I tried, and am happy to answer any questions for more detail, but let's start with a summary for now:

    - The Hoverfly manual has two different sets of ESC settings. One is inside the manual, in Table 3; it denotes Medium Timing and is silent about the Cutoff Threshold (default is Medium). The other is at the end of the manual, in the Quick Start guide; it denotes Low Timing and Low Threshold.

    - I had programmed all four ESCs at once, originally, using the Table 3 settings. When one motor seemed to be behaving differently, I went down the diagnosis path, including reprogramming it --- but using the Quick Start settings, not realizing they were different.

    - Even given all the above, three of the ESCs appear to be on default settings, or something awfully close. So I'm assuming I did something wrong three times out of four when I programmed them originally, but did it right the fourth time? I quite intentionally did all four at the same time in the same run, so I would do it the same way each time. But here we are, with three of them in default settings mode --- which I conclude from the observation that when I take my "lazy" one (just using the Industry Term here, no offense to the motor intended!) and tell it to reset to defaults, it suddenly behaves like the others. Setting it to Table 3 settings, or Quick Start settings, or several mixtures, makes it (comparatively!) "lazy".

    So my plan now is to start all over again and try to minimally touch the ESCs, that is to say program them as follows, per the Table 3 settings:

    - Reset to default
    - Battery to NiMH
    - Timing to Medium
    - Exit
    - Confirm exit by easing throttle forward and confirming motor spins up

    Now of course, I'm feeling really bad that Parallax went to the trouble of rushing me a new set of hardware, when it may well have been this strange only-one-got-programmed situation all along. Ken, I'd be happy to recompense you for the parts, in all fairness. Getting the new parts (and seeing them behave the same as the replaced one) was, realistically, a necessary step to considering the possibility that it was the _other 3_ that had an issue; but it isn't a step you should have to take a loss for. Please let me know what you think is fair.

    And ultimately of course for everyone reading this: if you encounter this kind of behavior,

    - Be open to the idea that it might be the three common units, not the one outlier, that's in a different programming state than you think.
    - Make sure you use only one programming approach, and don't trip over the Table 3 / Quick Start discrepancies.

    I'm headed to my folks' place in the country this weekend, lots of nice room to practice! Thanks again to all for your help.
  • Ken GraceyKen Gracey Posts: 7,392
    edited 2013-01-15 14:08
    icosmos72 wrote: »
    Now of course, I'm feeling really bad that Parallax went to the trouble of rushing me a new set of hardware, when it may well have been this strange only-one-got-programmed situation all along. Ken, I'd be happy to recompense you for the parts, in all fairness. Getting the new parts (and seeing them behave the same as the replaced one) was, realistically, a necessary step to considering the possibility that it was the _other 3_ that had an issue; but it isn't a step you should have to take a loss for. Please let me know what you think is fair.
    .

    You are most certainly welcome. It's our pleasure - please keep the extra parts because sooner or later you will need them. We support a flight team of at least five people at Parallax and they eat motors and ESCs for breakfast. For them, it's easy. They just walk back to the stockroom and pick up what they need. It's not that easy when you depend on the UPS guy to bring you the parts. Please keep the extra hardware and keep the ELEV-8 in the air!

    There are many quadcopter suppliers to choose from. We can be unique in this area because we offer the whole system, from Propeller to kit. And, if we can keep you in the air we will make this very different from all of your prior R/C experiences. Everybody is afraid of crashing, and how it's the "end" of their model. Quadcopters are very different in this way - a minor repair puts you back in the air [if you have the pieces].
  • StempileStempile Posts: 82
    edited 2013-06-20 15:36
    Ken Gracey wrote: »
    Everybody is afraid of crashing, and how it's the "end" of their model. Quadcopters are very different in this way - a minor repair puts you back in the air [if you have the pieces].

    I enjoy flying the EVEL-8 vs my Blade 450 Heli because of that fact, much easier to repair. I crashed the heli and replaced a handful of things, however still don't have it back in the air yet; won't even hover. Concerned I will need to take the heli all the way apart to figure out what is going on.
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