I’m trying to dig up more information how the Fan Switch Canopy module works to regulate speed control. Is it doing frequency modulation on the Hot Line to achieve the speed control? If so, does that mean there is essentially an infinite number of speeds that I can use?
What is there a maximum load that the Fan control can support? I cannot find the details anywhere in the docs.
I actually read it as being able to work on any AC Induction Motor < 1A.
However, that being said, the speed control can be done via different techniques, such as Frequency or Voltage Modulation, but each way implies different behaviour by the motor and the load/torque it can produce.
Hence the original question as to what kind of modulation it is doing on the Hot line to control the fan’s speed.
My understanding is that neither frequency nor voltage regulation are used. The fan speed is actually controlled by air friction across the blades (if you were to remove the blades from the fan and turn it on, it will spin very fast, even on low speed).
The control module uses capacitors in series in order to add reactance to the circuit, which reduces the current to the motor (reduces torque). The reduced current + the air friction from spinning results in a slower speed.
The module switches between 2 different capacitors depending on the speed you select. It works the same way as using the pull-chain on a 3-speed ceiling fan.
Capacitor 1 for low speed
Capacitor 2 for medium
No capacitor for high speed
Note: I am not an electrician. This is just my understanding of how things work, and I may be mistaken.