Connecting Motors and ESCs

Connecting motors to ESCs (electronic speed controllers) seems to be an easy task. However, things are not as easy as they look. There are several points to keep in mind. Otherwise, you will end up soldering and un-soldering motors and ESCs a couple times. Of course, once you’ve built a drone or two, you will do most things quickly and easily. However, for the first time mistakes are almost guaranteed. So, the goal of this page is save you time and energy.

There Are No CW or CCW Motors

You probably know that on quadcopters you have two motors spinning in the clockwise direction and two motors spinning in counter-clockwise direction. A common profile is given on the diagram.

quad-x-profile

Even though you need CW motors on positions 4 and 1 and CCW motors on positions 2 and 3, all motors can move in either direction. What gives a motor either a CW or CCW spin is the connection with ESC.

Keep in mind that with most ESCs you have to solder the wires in the specific way. There are some ESCs that can be flashed and thus the spin direction can be changed without changing wire connections.

Brushless Motors Do Not Have Positive or Negative Wires

Well they actually have three wires. How exactly brushless motors work is beyond the scope of this post, however, keep in mind that in order to change motor direction you have to swap two of the three wires.

So, in order to keep you from unnecessary soldering and un-soldering do this. Either use connectors or first connect motors and ESCs without soldering. Test the motor spin direction. Once you have figured out the correct connection, do soldering.

Don’t Forget the Prop Nut

Even though motors can spin in either direction you still have one thing that makes the motor either CW or CCW and this is the propeller nut. When I first soldered my motors, they moved in the right direction. However, I soon realized that the nuts moved in reverse direction. If you do not get this properly, your prop nuts may get loose. Needless to say what this will mean during the flight.

Relatively Easy Way to Test Motors

If you have your flight controller at hand, testing motor direction is easy. All you have to do is to connect ESC to the motor, connect ESC to the battery and connect ESC to the flight controller. Then you can use Cleanflight (or Baseflight) to test the motor. When doing this, please do without a propeller.

testing-motors-with-cleanflight