I completely understand that. I feel flitetest assumes we understand the Electronics. Seems like it could be an opportunity for some familiarization of the products they sell. Maybe they have and I'm not aware. Everything is a work in progress. I'm just offering my thoughts based on what I am running into.
Be careful, I must admit that i don't agree with some of what PoorMan RC said. I think that the flitetest B and A motor packs are more than adequate for the planes they're recommended for. In fact I think they're a little too powerful if anything. I'm not sure about the F-pack because I don't have one, but I'm sure that FT chose it wisely.
You can burn just about any ESC with just about any motor if you don't use them correctly.
To answer your question, you need to understand how motors work. In case you don't know this, let me explain. This might sound complicated, but if you take it step by step, it's really simple:
There is no electronic limit for the current in the ESC. A motor has very low resistance, so if you connect it to a 3S battery, a massive current will immediately be pushed through it - enough to burn both the ESC and the motor very quickly. It has one thing that can save it, and that's the back emf (electro motive force). As soon as a motor starts to turn, it generates a voltage ( back emf). The faster it turns, the more voltage it generates. How much voltage is generated is exactly defined by the kV, so a 1000kV motor will generate 1v at 1000 rpm and 12v at 12,000 rpm. That voltage is in the opposite direction to the battery voltage, so the available voltage to the motor is reduced. Let's see what happens when we apply this to the motor I got in my A-pack, which was an Emax 2213 935kv motor with a 3S (say 12v) battery :
At 1000rpm, the battery voltage is 12 v and the motor is making .935v in the opposite direction, so we have approx 11v pushing current through the motor. The resistance of the motor is .18 ohms, so we get 11/.18 amps =61 amps, which is easily enough to burn the motor and ESC.
At 5000 rpm, the motor is making 4.675 v, so we now have 12 -4.675v = 7.3v approx and the current will be 7.3/ .18= 40 amps, which is still enough to burn both.
At 9000rpm we get 8.4v generated leaving 3.6v, which will give 3.6/.18= 20 amps, which is just on the limit for the motor and ESC.
What this means is that the motor must run faster than 9000 rpm to be safe. If you hold it still, have an ESC that can't turn it properly or have too large a propeller on the motor, it won't be running at 9000 or more rpm, so something is going to burn. With the right propeller and the motor running properly, a higher speed will be reached and everybody will be happy.
In practice, there are some other important characteristics that affect it, especially efficiency, which also depends on speed, but the example above should give you a basis for understanding the relationship between speed and current.
I should add one thing. That's all assuming maximum throttle. At anything less, the ESC interrupts the current with high frequency pulses, so there is a sort of current limiting. The lower the throttle, the bigger the limit until it's totally interrupted at zero throttle. that's why it's OK to fly round at low speed with a low throttle.
Finally, when you give full throttle at low speed, the motor accelerates quite quickly to it's maximum rpm. At first, it does draw the very high current, but it doesn't stay there long enough for anything to heat up.
IMHO, your ESC burned because an electronic fault stopped it from turning your propeller at more than 9000 rpm. Bear in mind all the crashes you had. If the plane was on the ground and you still had the throttle on, you would have had 12/.18 = 67 amps going through the ESC, which could easily be enough to damage it, even though it didn't burn.
The numbers for your motor and battery will be different, but the principle is the same.
