ORIGINAL: Argess
Interesting video by the way. Where was the cap added? Must have been to the output side of the ESC to see the wavefrom change if it's voltage. If it were to the battery side of the ESC, the scope would have to show current I suppose, and that can be a bit tricky to set up.... Also, I couldn't see where the scope was set, but what frequency are the pulses at? Too low and you'll need a really big cap with the crazy currents you guys are running......chuckle.
Intial start-up = current limited by winding resistance (current goes down as motor speeds up, but high at first)
lower turns = lower resistance = high surge current
high surge current = higher starting torque
Therefore the 10000KV motor should have been better from a standing start. However as you mention, there are other variables.
In the video the cap was added on the battery end. The scope is showing voltage, more capacitance = less voltage ripple. It was a number of different low-ESR caps, all in parallel. One of the tradeoffs in designing an ESC is this PWM frequency, b'cos every time that switch flips, you having to move around gate charge (on the power MOSFETS), and you are having to move the mosfets through the non-saturated region of operation. Some ESCs allow you to set this PWM frequency with the advisement that higher = more heat generated by the ESC, but hopefully less at the motor.
Note that for a half-decent motor, the winding resistance isn't too significant.
A Neu 1515/1Y motor = 0.006 ohms resistance. Even if you run 100A through it, it's going to drop 0.6V, not too significant for a 2200KV motor designed to be run between 14-21V. It's only when you get to things like those cheap feigao motors or others that resistance can start to be significant. If you shorted a coil of this motor direct to a 20V battery, it would (try) to draw thousands of amps, in theory.
It's up to the ESC to limit the inrush current when power is first applied to the motor. High inrush currents are a problem you see often in the real world.
The strength of an electromagnet (the coil of a motor) is proportional to the current and the number of turns in the coil. Twice the number of turns means twice the strength per unit current.
But if you read the link below, it describes how coming up with an optimum electromagnet can be a more difficult problem.
http://en.wikipedia.org/wiki/Electro...d_by_a_current
With quality motors, it's not so much an issue, see above. The effect of the resistance is quite limited.