Cogging... - RC-Monster Forums

BrianG · 02.17.2009, 11:35 AM

What's_nitro: An inductive clamp (which is what you're talking about) probably could be used, but I'm not sure if it would be small enough to fit without taking up too much room. In these vehicles, weight and space are at a premium, which is why these ESCs are so small/light to begin with.

kostaktinos_mt: I believe Eagletree does use the shunt resistor method. No biggie just for playing around, but I don't think I'd want anything that introduced losses into my rig. I do agree it would be nice to have something like that, but I'm sure the price would reflect the additional circuitry. The time-delay, or integration, of the punch control setting is not perfect, but sure is better than nothing. And I do agree about the clock speed of the device needing to be fast enough to measure those milli-second pulses.

Doesn't eagletree sample faster than 10X/sec? I think that's the default, but IIRC, you can speed it up but at a loss of storage room.

kostaktinos_mt · 03.28.2009, 03:38 AM

hi,
sorry for the delayed response; it`s a long story...

brianG, the eagletree uses a hall sensor [not a shunt].
http://www.eagletreesystems.com/MicroPower/details.htm [4th line]

the max sampling rate on my v2 was 10hz, and i think it`s the same for the v3 [read the page of the link above].

i don`t think a hall sensor is expensive or physically large either... maybe a hall-sensor-equipped esc will probably need a stronger processor if a serious sampling rate is to be fully implemented along with the mathematics involved to close the feedback circuit fast enough [output current adjusting pwm correlative to throttle input; while at the same time looking for rotor position and all other stuff for proper commutation].

don`t know... maybe some will say it`s useless, but imo, a real current limiter [current controlling closed branch actually] can really help in a LOT of things [from reliability to traction control and efficiency tuning]...

on the other hand, brushless tech in rc is still a baby the way i see it... taking a look on what was happening 2 or 3 years ago and contrasting it to what happens now, makes me believe that...