From the labs of Mega Stumbler (AKA Kevin) comes a new creation. The 1-3s Brushless ESC tester. This tester helps troubleshoot speed controllers to aid you in a quicker and more successful repair. It also helps you quickly answer the question. What is bad, my ESC or motor?
The device is very simple. Using the proper adapter you hook up your ESC’s motor output to the tester. With the white plug on top we will call the phases from left to right C, B, and then A. With the tester in the same orientation the lights go from top to bottom A, B and C.
Each phase has 2 lights. There is one red light and one green light. The red light illuminates when the phase goes high. This means the battery power (+) is flowing through the FET and out the plug to what would be the motor if the tester was not installed instead. The green light illuminates when the phase goes low. This means the battery (-) AKA ground is flowing through the FET and out of the ESC to the plug. The unlit phase is the sensing phase. It is being used by the ESC for commutation timing.
If a light is stuck on all the time then that most likely means you have a FET that has failed as a constant short. If you have a light that is always out then you have an open FET. There are other possible causes but a failed FET is the most common.
Since you have to have a complete continuous circuit for the motor to work you will always have one phase high and one phase low. This means that the lights will always illuminate in pairs when operating the ESC. The exception to this is the initial “beeps” this will illuminate all 3 phases, 2 high and 1 low. The fact that the LEDs illuminate in pairs is the trickiest part of the tester. The tester will narrow the fault to either a missing high on one phase or the missing low on its assisting phase. However, knowing this will help you speed up your troubleshooting and find the defect.
This device is created completely in house by Kevin. The circuit board was designed and etched by him. The parts were hand soldered by him and the housing was designed by him and printed on a consumer grade 3D printer. This does not have the finish of a mass produced product by a huge company with a expensive design team. Instead it looks like a homegrown device made by a hobbyist because that is exactly what it is. A cool tool made by a hobbyist for a hobbyist.