How to Test a Speed Controller for a Brushless Motor

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Electronic speed controllers (ESC) have been in the radio-controlled (RC) hobby market for 25 years. Before that, mechanical speed controllers were the only option. Today’s ESCs utilize micro-controllers to squeeze every ounce of performance possible from the motors. Brushless motors and controllers are the latest addition to the RC world. These devices can be more complicated to set up and operate. Sometimes it becomes necessary to test these controllers to verify they operate properly before you use them in a race.

Connect the electronic speed controller to the throttle channel on the receiver. Make sure any power switches on the ESC are in the off position. Connect the output of the ESC to the motor. Brushless motors have three connectors, one for each phase. These connections determine motor rotation.

Turn the RC transmitter on to verify batteries are charged. Plug the lithium-ion polymer battery into the ESC. Ensure the throttle on your transmitter is set to zero.

Read the ESC instruction manual and follow the proper power-up programming sequence. For most units, turn on the ESC power at the switch and hold the set button until a tone emits or a light flashes. Squeeze the throttle 100 percent forward and release. Push the throttle 100 percent in reverse and release.

The controller should now emit a tone or flash a light indicating proper calibration of your controller. Squeezing the throttle should now drive the controller and turn the motor. If the motor is not turning the desired direction, turn off the ESC and switch any two output wires going to the motor.

Turn the ESC back on and verify that the motor now turns the desired direction. You have now verified that the ESC is functioning properly.

Things You'll Need

  • RC transmitter
  • RC receiver
  • 2 lithium-ion polymer battery packs
  • Brushless motor
  • ESC instruction manual


  • Never plug the battery into the ESC with the transmitter off. Never short the battery's terminals.


  • "RC Car Troubleshooting"; Jr. Defrancesco Louis; 11/1992

About the Author

Jay Macgruber has been writing documents and work procedures since 2005 in the science and technical industries. Part of his job at Fermilab National Accelerator Laboratories in Batavia, Ill. is to document service, repair and calibration documents. He holds an associate degree in electronics from Elgin Community College and a Certificate of Completion in HVAC From Joliet Junior College.

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