I'm a little confused on how (and how efficiently) speed controls for
ceiling fans work. I understand that there are two types of speed
controls--capacitor based controls (with discrete speed levels) and
triac based controls (which can be continuous). I'm using the Hunter
Vista fan, which has a capacitor-based 3-speed control built in. So,
a few questions:
1) How do capacitor based speed controls work? I was under the
impression that an induction motor's speed was fixed by its design
and the AC frequency.
2) Are the capacitor based speed controls more energy efficient than
the solid state controls? In particular, I understand that triac
based lighting dimmers use a small amount of power themselves.
Does this hold true for triac based fan speed controls, and not
hold true for capacitor based fan speed controls?
3) Will a wall capacitor based speed control work as well as the
built-in capacitor based speed control on the fan itself? I ask
because in the wall there are just hot and neutral, while the fan
motor has 4 wires going to it.
4) Is every "rotary action" discrete fan speed control going to be
capacitor based, or are some actually triac based? In particular
I'm interested in the Hampton Bay 750 450 discrete speed control,
I'll have to call them tomorrow to double check.