fan speed selector switch question

Reply

  #1  
Old 04-01-07, 11:19 AM
Member
Thread Starter
Join Date: Dec 2006
Location: orange county
Posts: 285
Smile fan speed selector switch question

Can someone please tell me how a wall 3 speed selector switch changes the speed of the ceiling fan it is controlling? One hot and one grounded conductor at fan/light combo. The electronics in the selector switch must be I'm sure, be clipping the sine wave, in three different ways. Is this correct? What are the limitations of such a switch, in terms of types of motors in can control? Can these switches reduce the speed of single speed motors, and what type of single speed motor would this have to be? Mostly I just want to know the answer to my first question. thanx in advance
 
Sponsored Links
  #2  
Old 04-01-07, 07:35 PM
Member
Join Date: Sep 2000
Location: United States
Posts: 18,497
If there is only one hot, then the wall selector is sending digital signals through that hot line to the receiver in the ceiling fan. It is really the box in the ceiling fan that is controlling the speed, not the wall control.
 
  #3  
Old 04-01-07, 08:18 PM
Member
Thread Starter
Join Date: Dec 2006
Location: orange county
Posts: 285
Thank-you John for your response. Do all house fans these days have built-in receiver boxes? I posted the same question in Wg's forum and I got a rersponse that was sound and made sense to me. Basically the speed controller interrupts power at certain programmed intervals to get the desired speed. Like plugging in and unplugging a fan at certain intervals. This is quite different then the method you are referring to. Certainly if a remote control comes with the fan then that would require a receiver (box in the housing) to be there. I also asked of this respondent, on Wg's forum if the method of on/off control is also the method used to control low voltage halogen lights. I look forward to the response. I think there is a Lutron man giving a lecture sometime in my area this month. I hope my schedule will allow me to be there. I look forward to having all these issues cleared up in my head, as I'll be installing an occasional fan for customers.
 
  #4  
Old 04-02-07, 06:08 AM
Member
Join Date: Nov 2004
Location: CA
Posts: 2,041
Modern light dimmers work the way you describe by altering the waveform, thus reducing the total RMS power. "Plain" motors will not work properly if you attempt to do this. A motor has to be designed to be either a multispeed motor or a variable speed motor, often this is a DC rather than AC motor.

In the past, ceilling fans were multispeed....the motor had different windings, and the speed control switch controlled what windings the voltage was applied to. Today, with the remotes etc fans are more complicated.

Bottom line, though, is ...you can only do what your particular fan was designed to do.
 
  #5  
Old 04-02-07, 10:39 AM
Member
Thread Starter
Join Date: Dec 2006
Location: orange county
Posts: 285
Smile

Thank you gentleman, things are clearing up.
 
Reply

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off


Thread Tools
Search this Thread
Display Modes
'