I know how to connect motor to Arduino with 3 wires: 5v, digital pin and ground. As I know only digital wire need to control "speed control" of my motor. So, if my Arduino connected to computer and it is not needed to get this 5v from "speed control". So I decided to remove useless 5v and ground wires. When I remove ground wire, it is okay. But when I remove 5v wire, my motor works about 3-5 seconds on random frequency and then die. So, can I use only 1 digital pin to control my motor?
What you have a is a DC brushless motor of type A2212/10T 1400KV. In order for the motor to work you need all three wires. The motor has 3 winding's. Below is good image describing the motor.
When you connect two wires example R or L1 at 12V and Y or L2 at 0V only the winding w1 and w2 are energized. So motor will turn a little bit and stop, as you indicated.
Below is an image of the inside of the motor.
So in order for motor to continue to turn you have energize the another pair of winding's. Take a look at the sequence below.
I hope I answered your question. Take a look at the references below.