Esc Fundamentals
08-26-2003, 12:26 AM
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Esc Fundamentals
What does the wattage rating mean on an ESC?
1) Is it the maximum this can deliver without starting to smoke?
2) Is it the maximum this can deliver without cutting out?
3) Is it the point at which it is suppose to cut off?
What are the symptoms of the wrong size?
If it is too high a wattage rating it...?
If it is too low a wattage rating it...?
I also understand brushless work differently, do the same rules apply?
Thanks in advance for your reply, I am just trying to piece all these things together. It gets expensive to buy a new ESC with every new set up.
Larry
1) Is it the maximum this can deliver without starting to smoke?
2) Is it the maximum this can deliver without cutting out?
3) Is it the point at which it is suppose to cut off?
What are the symptoms of the wrong size?
If it is too high a wattage rating it...?
If it is too low a wattage rating it...?
I also understand brushless work differently, do the same rules apply?
Thanks in advance for your reply, I am just trying to piece all these things together. It gets expensive to buy a new ESC with every new set up.
Larry
08-26-2003, 10:46 AM
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Esc Fundamentals
ESC ratings are normally maximum CONTINUOUS. That is the maximum number of cells and the maximum current the ESC can withstand on a continuous basis. 40 Amp ESC means you can draw 40 Amps from the time you take off until the time you land. Of course, that was before LiPoly batteries... Theoretically, the ESC should be able to take it, but personally, I wouldn't run my 40 Amp ESC for 30 minutes straight at full power.
Some ESCs are underrated, meaning you could run them at higher-than-rated currents. How are you going to tell which ESCs are underrated, though? It could get mighty expensive, burning out ESCs trying to test their limits.
Using an ESC that's overrated for the application, i.e. a 40 Amp ESC on a plane where peak current is 20 Amps, is no big deal. You're hauling a little extra weight around, but that's it. The larger ESC has more mass to dissipate heat, and will run cooler than a "correctly-sized" ESC running at full capacity.
One thing about brushless ESCs is that you NEVER want to try running them beyond their rated capacities. At partial throttle settings, the ESC actually has to handle more current than at full throttle because of the three-phase AC nature of the beast.
Some ESCs are underrated, meaning you could run them at higher-than-rated currents. How are you going to tell which ESCs are underrated, though? It could get mighty expensive, burning out ESCs trying to test their limits.
Using an ESC that's overrated for the application, i.e. a 40 Amp ESC on a plane where peak current is 20 Amps, is no big deal. You're hauling a little extra weight around, but that's it. The larger ESC has more mass to dissipate heat, and will run cooler than a "correctly-sized" ESC running at full capacity.
One thing about brushless ESCs is that you NEVER want to try running them beyond their rated capacities. At partial throttle settings, the ESC actually has to handle more current than at full throttle because of the three-phase AC nature of the beast.
