How to quieten fan motor driven by a triac dimmer?

MrAl

Joined Jun 17, 2014
6,970
How about a graph of what MikeA is using. At the speed he wants to run it. Fan and Dimmer..?
Hi,

That would be like the more symmetrical graph shown but would have more bumps.
The problem with that method is the frequency is not decreased which is part of the goal of creating a good speed control for this kind of motor. We all believe that the best speed control for this kind of motor is one that reduces the voltage AND reduces the frequency too, but ideally keeps the waveshape a sine wave also. This can be done exactly with a frequency converter (AC to AC) but that's a much more complicated circuit.
 
correct MrAl . read his first post.
were not supposed to believe him. ? when he says "I'm using a fan and a dimmer." I've hit that from every possible direction I can think of. except telling him that the noise is coming Via the scr IN his Dimmer not firing at the optimal time of the sign wave. And because it can only follow the frequency (60hz)(not 400 or 1200) it is given. And Caused by the pot trying to come up with enough mA to fire the gate.
And I gave other possible solutions with less complicate answers and less costly out comes. no one seams to care what the original statement was. sham-pain on a bear budget. ($100.00 vfd to run a $20.00 Fan)
or an actual solution: tightly wind a Phillips screw driver with a piece of 14ga. solid wire about twenty turns with the insulation still on the wire and put that in series with the circuit and see if the noise gets less. Then tune the circuit by sliding the screw driver in and out of the coil.
No I'm not Mad or Angry... I am confused that no one will answer his actual question...I think there should be some high precision here too.
next ...Yes I'm not an English major.......
yea, I guess I got a little windy, and MikeA said he wanted less wind and noise. I'll shut up now.
 

tcmtech

Joined Nov 4, 2013
2,868
No I'm not Mad or Angry... I am confused that no one will answer his actual question...I think there should be some high precision here too.
I answered the problem back in post 16 with more than enough precision to get the job done right and under budget. :rolleyes:

Thanks for taking the time to read it. :oops:
 

tcmtech

Joined Nov 4, 2013
2,868
I'm very patient. I say what I know from experience that will likely work as the OP needs and then let everyone else say and do whatever they want.

The most confusion I get is why some feel the need to pursue outrageously complex, costly and quite often what will be highly finicky methods to avoid largely made up 'what ifs' to do simple functions as this thread has shown. :rolleyes:
 

#12

Joined Nov 30, 2010
18,182
the need to pursue outrageously complex, costly and quite often what will be highly finicky methods to avoid largely made up 'what ifs' to do simple functions as this thread has shown. :rolleyes:
Or largely made-up, "problems". Once upon a time I had a customer who said, "Late at night when there is no car traffic, no television, and the air conditioner is not running, I can hear the fluorescent lights when I sit right next to them." I installed 12 different ballasts before she was satisfied with the sound level. Then she asked me if I thought she was crazy. I said, "Yes" and cashed the check.

This site doesn't pay enough for me to answer, "problems" like that.
 
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