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hysteresis or other effect

Old 09-07-2006, 09:55 PM
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Aschiuta
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Default hysteresis or other effect

I have a ULTRAFLY B12/12 and i noticed something weird. I have an Eflight ESC 40 A and 2 cell 1400 mah.
I start the motor (for testing only) with a APC 10x4.7 for about 10 sec in full power. Then i disconnected the battery, and i noticed when i was turning the prop by hand, i did not feel the same "resistance" cogging from before starting the motor. i thought i am crazy, but then after a couple of hours, i felt again "normal" cogging when i turned the prop.
Is there some sort of hysteresis or something, that will make the magnets to have a different behavior ? immediately after the motor run ?

I also have to mention that the motor seems to run just fine, lot of power, and no weird sounds or anything.
Thanks
Old 09-07-2006, 10:06 PM
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Slo-V Flyer
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Default RE: hysteresis or other effect

Lol. I know exactly what you're talking about. I have the 20A ESC from Eflite.

That I believe is the braking effect that the ESC has when you turn off the throttle under normal operation. My theory is that there is some residual power left within the ESC after unplugging it, and so you "feel" more resisitance after unplugging, as the ESC is trying to stop the "prop" from "windmilling" because it "thinks" the throttle is at 0%. And yes the effect does go away after several minutes of being unplugged. Probablu due to how they designed their controller a certain way, don't worry your ESC should be fine.

[8D]
Old 09-07-2006, 10:11 PM
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Default RE: hysteresis or other effect

Interesting, but the battery is disconnected, so i am puzzled what the ESC can store in it :-) ! and also by default (the manual says so) the brake is disabled. I am more curios to know what the explanation, how this "effect" is possible.
Anyway, thanks!
Old 09-07-2006, 10:22 PM
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Default RE: hysteresis or other effect

Yes I know the battery is disconnected, so my best guess is all the tiny capacitors within the circuitry may have some left over voltage from when you last run it, but you say your brake is off by default, so I'm kinda puzzled. Also, don't forget that when you rotate the shaft you are creating a small amount of electricity (like a headlight dynamo in a bicycle) so that may somehow provide some power the ESC needs to "go into action."

About the brake, are you sure when you cut the throttle the prop just coasts to a stop or does it come to an almost abrupt stop (like mine does with the brake on)? [sm=confused.gif] Also, when powered up, if you have yout throttle at 0%, when you try to spin the prop by hand (at your risk) do you feel that same weird resistance or does it cog normally?
Old 09-08-2006, 05:44 AM
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Default RE: hysteresis or other effect

I will "re-program" today the ESC to have the brake off and i will do more tests. The ESC capacitors might be also an answer.
Anyway, tomorrow is a big day, as i want to fly the Piper J3 for the first time with this ESC and motor.

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