Electrical tech Question for Growlush fan speed controller

[nici]

Hi all,

 

Ive got a tech question regarding the Growlush fans speed controller hooked to a Can fan (RS100). When using said fan speed controller and lowering the RPM of the fan, I get an electrical hum at the fans junction box which is quite noticeable. Just wondering if this is some kind of electrical feedback to the fan from the controller.

 

Has anybody else noticed this? What type of controller do other peeps use??

 

Cheers

[wayno86]

hey there nici...

 

i used to run my fans on fan speed controllers(1 fan per controller), never use light dimmers....

i have now taken the speed contoller out, and insulated my fans and ducting

now both inlet and outlet fans run almost silently at full speed

 

the humming you can hear is harmonic feedback, this is something that happens when you try changing the speed of a motor.

i would not run the fans any slower than 25% of full speed, below 20-25% can severely reduce the life of the motor

 

 

there are 2 ways to fix this problem:

1 - Buy a fan that you dont need to slow down...

2 - Insulation, insulation, insulation..

make a sound proof box to put the fan in, there are a few posts around here to show you how.

use acoustic ducting, or wrap insulation batts around your ducting

 

wayno :bongon:

Edited September 26, 2012 by wayno86

[nici]

Cheers Wayno, thought it was something along those lines but just wanted to check! Not going to be running any less then 50% (more around the 75% mark) so all good