Connect ESCs and Motors

This article explains how to connect the ESCs, Motors and Propellers for Pixhawk, PX4, APM 2.x. and Erle-Brain2.

Connect motor PWM signal outputs (Pixhawk/PX4)

Connect the power (+), ground (-), and signal (s) wires for each ESC to the controller main output pins by motor number. Find your frame type below to determine the assigned order of the motors.

../_images/Pixhwak_outputs.jpg

Pixhawk Outputpins (numbered). First 4 pins are colour-coded for connecting a Quadframe

Connect motor PWM signal outputs (Erle-Brain2)

When connecting the ESCs directly to autopilot board, connect the power (+), ground (-), and signal (s) wires for each ESC to the controller main output pins by motor number. Find your frame type below to determine the assigned order of the motors.

../_images/3dr_power_distribution_board.jpg

Note

Be sure you connect the ESC connector in the right way. Signal goes on the top of the rail (white or orange color wire) and ground at the bottom (black or brown color wire)

Connect motor PWM signal outputs (APM2)

There are two methods of connecting the motor outputs: connect the electronic speed controllers (ESCs) to autopilot controller board directly or use a power distribution board (PDB).

Warning

The APM power distribution board PDB described here is not compatible with the Pixhawk, PX4 or Erle.

When using a PDB, connect the power (+), ground (-), and signal (s) wires for each ESC to the PDB according to motor number. Find your frame type below to determine the assigned order of the motors. Then connect the signal wires from the PDB to the main output signal pins on the flight controller board (ensuring that the motor order numbers match the main output pin numbers on the controller). If you are using a power module, it is optional to connect the power and ground wires from the PDB to the flight controller board. If you would like to use these cables in addition to or instead of the power module or as a common point for low current servos, connect the ground (-) wire to a main output ground (-) pin and the power (+) wire to a main output power (+) pin.

Note

Information on assembling PDB is found here for Quadand here for Hexa.

../_images/3dr_power_distribution_board.jpg

When connecting the ESCs directly to autopilot board, connect the power (+), ground (-), and signal (s) wires for each ESC to the controller main output pins by motor number. Find your frame type below to determine the assigned order of the motors.

../_images/APM_outputs.jpg

APM Output Pins (numbered)

Motor order diagrams

The sections below show motor order for each frame type (the numbers indicates the connected autopilot output pin) and the propeller direction (clockwise (CW) motors are shown in green and take pusher propellers,counterclockwise motors (CCW) are shown in blue and take puller propellers.

Use the diagram for your frame type, and wire the motors as shown.

../_images/MOTORS_CW_CCWLegend.jpg

Legend for motor-order diagrams

Quad

../_images/MOTORS_QuadX_QuadPlus.jpg ../_images/MOTORS_Quad_Hb.jpg

Hexa, Octo, Y6

../_images/MOTORS_Hexa-octo-y6.jpg

X8

../_images/MOTORS_X8.jpg

Tricopter

../_images/MOTORS_Tri.jpg

Note

If the direction of your tail servo is going the wrong way in response to yaw then either the RC7_REV or MOT_YAW_SV_REV parameter should be set to -1 (from 1), See TriCopter setup page for details.)

Attach propellers

Find your frame in the motor order diagrams above. Clockwise motors are shown in green, marked CW, and take pusher propellers. Counterclockwise motors are shown in blue, marked CCW, and take puller propellers. Use the diagram for your frame type, and attach propellers to your vehicle as shown. For copters, attach propellers with the writing facing towards the sky. For more information on recognizing the different types of propellers, see the next section.

../_images/APM_2_5_MOTORS_HEXA_OCTA.jpg

Recognizing clockwise and counterclockwise propellers

The diagrams above show two types of propellers: clockwise (called pushers) and counterclockwise (called pullers). Pusher propellers are often marked with a P. However not all propellers are marked and both types are often available in either rotational direction. Therefore, it is most reliable to recognize the correct propeller type by its shape as shown below. Note that the propellers below have the edge with the shallow consistent curve at the leading edge in direction of rotation and the more radical scalloped (and usually thinner edge) as the trailing edge. You can use these features to recognize propellers of the correct direction of rotation. prop_direction

Choosing propellers

Propellers come in many varieties and are suited to different needs.

Note

Have experience choosing propellers? Help us by editing this section!

Testing motor spin directions

If you have completed the Radio and ESC calibration, you can check that your motors are spinning in the correction direction:

  1. Make sure there are no propellers on your copter!

  2. Turn transmitter on and ensure the flight mode switch is set to Stabilize.

  3. Connect battery.

  4. Arm copter by holding the throttle down and rudder right for five seconds.

  5. If it fails to Arm with the throttle down and to the right and the motors will not spin, it has probably failed the Pre-Arm Safety Check.

    • Pre-Arm safety check failure is also indicated by the red arming light double flashing and then repeating.
    • If the Pre-Arm check fails go to the Prearm Safety Check Page and correct the problem or disable the check before continuing.
  6. When you can Arm successfully, apply a small amount of throttle, and observe and note spin direction of each motor. They should match directions shown in the images above for the frame you’ve chosen.

  7. Reverse any motor spinning in the wrong direction.

    Tip

    Motor Direction is reversed simply by interchanging two of the

    three ESC to motor power leads.

Checking the motor numbering with the Mission Planner Motor test

An alternative way to check that the motors have been hooked up correctly is to use the “Motors” test in the Mission Planner Initial Setup menu.

../_images/MissionPlanner_MotorTest.png

Mission Planner: Motor Test

When connected to the vehicle via MAVLink, you can click on the green buttons shown above and the corresponding motor should spin for five seconds. Letters correspond to motor numbers as shown in the example below.

  • Take off your props first!
  • If no motors turn, raise the “Throttle %” to 10% and try again. If that doesn’t work, try 15%

The first motor to spin will be the one located directly forward in the case of + configuration, or the first motor to the right of straight forward in the case of X configuration. The motor test will then proceed in a clockwise rotation.

../_images/APM_2_5_MOTORS_QUAD_enc.jpg

In the case of X8, it will spin the top front-right motor first, then the bottom front-right, and proceed around with the same pattern.

OctoV will spin the front-right motor first, and then again, proceed clock-wise until reaching the front left motor.

KDE (and other) Opto Isolated ESCs

The KDEXF-UAS and KDEF-UASHV Series are opto-solated and do not provide BEC power output for the peripheral equipment. They require +5V to power the opto-isolator and while the Pixhawk can be powered from the servo rail, it does not provide +5V to the servo rail. The ESCs must be powered by a BEC or with a jumper from an unused connector on the board. It is strongly recommended that you use a BEC to power the rail rather than a jumper.

../_images/Pixhawk-Correction-to-KDE-ESC2.png

The KDE ESCs have fixed PWM ranges so you must manually set the output range of each PWM signal so that RCx_MIN is 1100 and RCx_MAX is 1900us using the Advanced Parameter or Full Parameter Settings Page in the planner.

Pixhawk ESC issues

Some ESCs have been reported as not working with Pixhawk.

The Pixhawk should work with every ESC that works with a normal RC receiver (because it sends the same type of signal) but there is one known exception, the EMAX ESC.

In most cases problems are due to incorrect wiring. Always connect signal and ground. Check your ESC type to decide how to connect the +5V line. On APM2.x you could get away with using the power ground as the signal return with the APM but for Pixhawk you must connect both the signal and the signal ground in order to make the ESC work.

For more information see this page and the video here.