Currentlimiting esc funktion ?

[speedy]

Some castle hv esc.
,s have an currentlimiting funktion
How does that work ? How can the esc limit the amount of current flowing thrue it ?

I,m hinking of building a brushless brushcutter/weedwacker with a rotomax 50cc outrunner on 12s lipo in it
But i only need 2800w max poweroutput from it and it can handle 5000+ watts.

So it chould run very cool and effichent if i limit the current so that it only putsout 2800w tops?

[RokleM]

Current, punch control, etc. Basically lowering the number will decrease the huge burst of power on initial throttle. It smooths things out, makes things easier for those that are trigger happy, and can save some battery power. I'm not 100% sure on castle, but most of the limiters shut off as of certain RPM or range, so it only really changes the low end initial take off.

[A RC Dude]

Correct me if I'm mistaking, but the ESC runs on a PWM (pulse width modulation) signal from the receiver, I know the servos do (ever plug an ESC into the wrong channel by accident? It still works correctly)

PWM works by turning on/off extremely quickly (it only feels like partial throttle)


I know that in servos, the interval is 20 milliseconds and an "on" period of 1-2ms controls what angle it turns to.

For an ESC, it has some as equation involved to make the 1-2ms signal stretch from 100% forward to 100% backwards. If the ESC knows the resistance of the motor (witch I believe is closely related to the kv rating) then it can take the voltage it reads and resistance of the motor and limit the PWM at a certain percentage.

Or at least that is my guess, but it does seem like a crude way of doing it. If I knew of a current sensor that worked in DC and didn't take much space, then I'd say it takes a reading from that.

[speedy]

Hm.......?
So with if i set the current limitm to 80amps i won't get the same max rpm on the motor ? With low enough loadmon the motor so it doesn't need more than 80amps ?

The reason i whanted to limit the current draw are that because the motor will be powering a bushcutter or weedwacker and if the blade hits a stone or get's tangled in grass i don't what eanething to fry :). And the motor can put out 2300w more than i need.