Multiple windings on the motor I think. Various combinations are used for separate speeds. That is why cheap fans never have continuous speed control. Bob Ammerman RAm Systems ----- Original Message ----- From: "Dmitriy A. Kiryashov" To: Sent: Sunday, March 10, 2002 9:00 PM Subject: Re: [EE]: What about 115 AC fan control? Was: Thanks DaveDilatush! (AC switching revisited) > Hi Thomas. > > Any other ways to control AC motor ? > > I guess there should be more simple tecnique to control AC fan. > Original manufacturers they using resistor in series I think > (what else they can switch inside of cheap Holmes fan ? ) > Actually I didn't open a unit yet to prove that. > > Also I'm not afraid of non trivial challenges I like them ;) > > > WBR Dmitry. > > > > "Thomas C. Sefranek" wrote: > > > > Dmitriy A. Kiryashov wrote: > > > > >Hi Dale. > > > > > >Can that circuit be used for 115 AC fan control? ;) > > >Sometimes I feel like my brain and body are overheated > > >(no kidding ;) Fan is helping alot but it only has two position: > > >very fast blow and medium blow. I can't stay under it for long > > >unless I want to catch a flue. So I'm thinking to put some > > >controller in series to it. Implemeting PWM code would be easy, > > >probably some indication (like one digit 0..9 is enough) > > >couple buttons (increase and decrease) what else I'm missing? > > > > > Most AC motor's speed are more dependent on the frequency of the AC than > > the voltage. > > Now, you CAN build a sine wave of variable frequency with PWM in a class > > D amplifier fashion, > > but it is non - trivial. > > -- > http://www.piclist.com#nomail Going offline? Don't AutoReply us! > email listserv@mitvma.mit.edu with SET PICList DIGEST in the body > > -- http://www.piclist.com#nomail Going offline? Don't AutoReply us! email listserv@mitvma.mit.edu with SET PICList DIGEST in the body