I am building a controller for a fan. It is a household fan similar to a box fan. This is it here.
Basically the fan will plug into my device which has a relay to control the fan and the device is plugged into the wall. Think of it as a relay in a box. The fan will be left in the on-low position 99% of the time and may be set to medium or high on rare occasion. The fan will be cycled on/off normally only once or twice a day.
The fan is 120VAC. I have measured the following on it, but I don't really know anything else.
|Mode||Amperage||Power off resistance|
I know that when you have an inductive load it is best to have some manner of snubber to handle the induced voltage when the relay opens. My first question is, since a fan like this has its own power switch, does that imply that there is already a snubber installed in the fan to keep the switch from arcing when you turn it off?
If not and I were going to add a series RC circuit across the fan motor do you guys know what would be the correct values of R and C to start with? I have researched this quite a bit and my head is swimming from all of the seemingly non-definitive data that is out there. Though I have found some examples of formulas where people calculate the correct values, but you seem to need to know the motor's inductance and stuff like that, which I just don't know.
Any insight is greatly appreciated. Please let me know if further data/explanation is needed.