Slowing a centrifugal fan?

meaty

meaty

Active Member
G'day, fellow growers. I've acquired a reasonably powerful centrifugal fan (200litres/s or ~420cfm), but for my current use it's far too powerful. I was hoping to significantly reduce its speed with a speed controller of sorts, but my local hydro doesn't stock them. For privacy reasons, unfortunately Ebay isn't an option.

I was thinking a variable transformer might do, such as this, but I think you'll agree that it's a bit overkill. Slightly.

Although I'd prefer a simple off-the-shelf item, I'm not electrically squeamish, so a DIY isn't out of the question.

I'm not even sure if this would work with my centrifugal monstrosity, but looking at this fan speed controller, does anyone know if its insides merely consists of something like this controller?

Is a reduced voltage even going to alter a centrifugal fan's speed or do they work via the frequency? :-?

Anyway, ideas are much appreciated. The fan specs:
  • Nuaire K200L TW
  • Revs. per second: 44
  • Air: 200 litres/s
  • Wattage: 165W
  • Amperes: .73
  • Voltage: 240 (AC @ 50Hz)
 
VictorVIcious

VictorVIcious

Well-Known Member
Hey Mate, Al B Fuct is the one you need for answers to what to use In Australia. Your main voltage is different than in the US. VV
 
JonnyBlunt88

JonnyBlunt88

Well-Known Member
too much info, just get a little fan from some hydro website. Do some research and get a fan that will fit your setup. Jesus. summarize your next update. its more interesting.
 
meaty

meaty

Active Member
Great to know, Victor. I'll see if Al responds before asking directly.

Jonny, the details hardly hurt, given the topic. I picked this fan because it was the smallest strong enough for a carbon filter. It just needs to spin slower, 'sall.
 
VictorVIcious

VictorVIcious

Well-Known Member
I understand. Some times he is off for an extended period though. Tell him VV sent ya. Check out his posts. You may even find an answer in one of them. VV
 
meaty

meaty

Active Member
Shall do, mate. It looks like he's been gone a month, but I'll hold my breath. Whatever the case, thanks for pointing him out, as he's a wealth of information. :)
 
X

xxr00fxx

Active Member
If you have any knowledge of electronics it would be easy to crack it open and soder in a few resistors. That should slow it down a bit, but you would have to play with the ohms or calculate it out on how much to use depending on your desired speed.
 
meaty

meaty

Active Member
Xenon, if we had Walmarts in my part of the world (Aus), it'd be so much easier! I should be able to locate something at the local hardware store, though.

Roof: True - a potentiometer/rheostat might be worth a try, as I'm mostly playing by ear as to how fast I need it. But that's my main problem. I don't know whether the fan speed is actually controlled by the voltage. Certainly worth trying, though.
 
D

Damurphy

Active Member
I'm just in the process of installing the same fan in our asbestos laboratory. We are using an off the shelf speed controller.
(Looks just like a dimmer switch). It is called "Fan Speed Controller 500VA" and it is sold in Australia by Fans Direct in Victoria. Call 1300 733 833.


meaty said:
G'day, fellow growers. I've acquired a reasonably powerful centrifugal fan (200litres/s or ~420cfm), but for my current use it's far too powerful. I was hoping to significantly reduce its speed with a speed controller of sorts, but my local hydro doesn't stock them. For privacy reasons, unfortunately Ebay isn't an option.

I was thinking a variable transformer might do, such as this, but I think you'll agree that it's a bit overkill. Slightly.

Although I'd prefer a simple off-the-shelf item, I'm not electrically squeamish, so a DIY isn't out of the question.

I'm not even sure if this would work with my centrifugal monstrosity, but looking at this fan speed controller, does anyone know if its insides merely consists of something like this controller?

Is a reduced voltage even going to alter a centrifugal fan's speed or do they work via the frequency? :-?


Anyway, ideas are much appreciated. The fan specs:
  • Nuaire K200L TW
  • Revs. per second: 44
  • Air: 200 litres/s
  • Wattage: 165W
  • Amperes: .73
  • Voltage: 240 (AC @ 50Hz)
Click to expand...
 
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