How to control AC fan speed?

[james_s]

There’s this thing companies do, called “exporting”, where they sell things to customers in other countries. And to do that, they need to make the things the customers in those other countries want.

Where you live, you can identify things that were exported to USA because the “made in [country]” declaration will name a country other than “USA” or “America”. For example, if you buy a real Swiss Army knife, the box will say “Made in Switzerland” (which is a real place, not a fantasy thing made up for a theme park!). Sometimes, manufacturers will leave off the “made in” part and just write a country name on the thing.

Obviously I know that all that, I'm not an idiot. The USA has been far more well known for importing rather than exporting in recent decades though, I don't recall seeing much if anything made by well known American brands when I have visited elsewhere and even here in the USA it's far less common than I'd like to find domestic products. American appliances are rare in the typical smaller European homes, and there are loads of European brands. Obviously we must export some stuff still but I'm surprised to see something as mundane as a fan motor exported from here.

[Zero999]

One way of controlling motor speed is with a triac, then turn it on for a half or a full cycle, then turn it off for a few (half) cycles. Some 30 (+) year ago this used to be done with some 555's and but these days it's more logical to use a small uC for this, and you can probably find a few of such projects on those git collection websites.

That's burst control and is not normally done for motors, because it causes vibration. Phase control is much more common for motors and is easier to do, with a TRIAC, DIAC and RC circuit.

[eev_fan]

I ended up using a 220-110V transformer for the low speed winding.