Electronic – Controlling a 3 speed AC ceiling fan motor with a Raspberry Pi

acmotorraspberry pi

I have been trying to reverse engineer a ceiling fan remote control receiver to work with a Raspberry Pi Zero W. The light portion of the fan was easy enough to control, but I can't figure out how to control the motor. From what I've been able to figure out, the motor has 3 speeds and runs on 120v AC at 60hz. Here is a picture of the motor controller that I've extracted from the motor:

motor controller

Here is the cover in higher resolution:

cover zoomed

Here is my current schematic:

schematic

What should I use to control the motor that can be controlled by a Pi? It could either be pre-built (as long as it's not too expensive) or hand-built.

Best Answer

The remote control receiver is marked "Capacitor Fan speed Control." I expect that it has provisions for selecting a low, medium or high fan speed. I expect that is done by connecting the yellow wire to the black wire through a low-value capacitor, a medium-value capacitor or both capacitors in parallel. If that is the way it works, you need to find those two capacitors or two capacitors in one 3-lead package. Remove them or it from the controller and get two relays to connect them with your system. You will need a third relay to turn the fan on and off.

See also my answers to these two questions:

Varying run capacitor for speed control of single phase motor

Calculating the capacitor values to control ceiling fan speed