What happens to the ESC

[sephiroth720]

I always wondered what happens to the ESC when you put in a motor that it can't handle. Does the motor not work at full capacity or does it just blow the ESC? Consequently, what happens when you put too many cells in? Does this just blow the ESC? May be stupid questions, but just a thought....

[RC10DS99]

I belive it will just burn out your ESC. it would probley start smoking and pretty much be wrecked.

[Nairb]

ESCs are designed to withstand the flow of only so much current. If you throw in a motor with fewer turns than recommended, it will s u c k juice like crazy from the battery, which will be more than the ESC can take. This will cause meltdown, in other words, it will sizzle and fry. The temperature increases because of resistance.


Think of it this way, you have a hose with a small hole in it. The hole represents resistance and the hose represents the ESC. If you run a small amount of water (current) through the hose, you'll get a small leak (heat) that will be easily absorbed by the ground underneath it. This is basically what the heatsinks do to release heat caused by resistance. When you force more water (current) through there, the hose will leak much more water at a faster rate, and the ground can't soak it up fast enough, so it floods (overheats). In ESCs, when more heat is caused by same resistance to more current and the heatsinks can't disperse it, the electronics melt and stop working how you want. So, better ESCs have smaller and smaller resistance (smaller and smaller holes in the hose) and/or can disperse heat faster, so they can carry more current without getting too hot. Get it?


OK, the voltage situation is similar. V is voltage, I is Current, and R is resistance in this equation. V = I*R The ESC's internal resistance is fixed, and it can only handle so much current before melring down, so you throw those in the equation and you get what Voltage the ESC can handle. When you increase Voltage, you increase Current, and the same thing happens as above.


How's that explanation? http://www.rccaraction.com/ubb/biggrin.gif

[This message has been edited by Nairb (edited 02-23-2001).]

[sephiroth720]

Thanks! Looks like physics and electricity class are actually paying off!!! With the info you just gave me, maybe you could help me figure out something. You brought up how V = I * R. How do you know how much current motors draw. I know the voltage is 7.2V, and the resistance on my ESC is .0125 ohms. I want to know how fast of a mod motor i can use. Is there a formula to figure a current reading for motors?