Question on speed controlling fans

Discussion in 'Grow Room Design/Setup' started by SpruceGoose, Jan 21, 2010.

  1. Hoping there are some experts here who can provide some assistance. I have a Soler & Palau TD-150 mixvent fan, and while the fan itself is extremely quiet I'm finding the WOOSH of air to be a bit too much. I understand there are mufflers, insulation/duct wraps and other things to help in this area, but my question here relates particularly to adjusting fan speed to reduce airflow and the associated noise. I haven't been able to find any consensus among growers about speed controllers, so hoping some of you may have been down this road before and can provide guidance.

    My knowledge in this area is limited, so please correct me if I have gotten the following wrong, but my understading is as follows. Basically I've heard of two methods for limiting fan speed, triac and variac controls. Triac controllers like the Speedster work by esentially chopping the AC waveform to limit total power. Variac controllers on the other hand work by limiting the voltage going to the device.

    The problems I've heard about with the triac controllers is that they will wear out your fan motor and create a hum. I've heard this hum myself when plugging my S&P TD-150 into a Speedster. Variacs on the other hand seem much more problematic. Wattage equals volts x amps, and if you limit the voltage and a device is made to work at a particular wattage then it will draw more amps to attain the operational wattage and risk overheating that could cause a fire.

    Going back to the Speedster for a minute, since that seems to be a popular option, and is sold in many grow shops, is it safe for operation and how much would it limit fan life? The Speedster instructions say it should only be used with universal brush type motors, however, most centrifugal fans, like the ones from Vortex and Fantech, are not brush type motors. Is that why the fans hum, because they're not designed to be operated in this way?

    S&P fans are a bit different from conventional centrifugal fans. The smaller ones use a shaded pole motor which can be safely used with a variac, since they're designed to limit the current even if the voltage is reduced. The larger fans, TD-150 included, use a single-phase permanent capacitor motor which would draw more amps if voltage were limited. This is why I tested the Speedster as opposed to a variac controller on my fan, not wanting to risk burnout.

    Given that there seems to be downsides to both methods of speed control is there a safe and reasonably affordable ($100 or less) alternative method of limiting fan speed? Does anyone have a recommendations or experience running a Speedster with an S&P TD-150 that they could share? Can the hum be reduced, or is it the price of using a Speedster, and are there any dangers of using it, such as fire, that I should be aware of? At the moment I'm leaning towards using the Speedster, but I want to be sure I'm not creating a safety issue.

    Thanks for taking the time to read this, and my apologies if I've got something ass backwards.
  2. i found having the same problem not getting enough or a hurrcane so i just hookup a dimmer switch to mine now i can run my fan at any speed i want im on my forth grow with same fan
  3. I want info on this too... so BUMP :)
  4. Yeah Ive been looking for info on this too. What about axial fans? Could you use a regular light dimmer knob wired the right way?
  5. Fuck rigging a light dimmer. I got the $20 fan speed controller from HTG, they have a fuse wired in, and are designed for running with inline duct fans.

    I have one hooked into a 4" GrowBright 170 CFM fan that runs the exhaust/scrubber in my 2x2x5 closet cab. I usually keep it on med/low and can hear no whooshing with my closet doors closed. Only thing I can hear is the slight hum of the motor, which is just a tad bit louder than my ceiling fan. I always have music playing in my bedroom anyway, and when there's no music, I bump ambient noises to drown out the hum (either rain or ocean waves, relaxing too :smoke:).
  6. I basically want to know of brands of Variac controllers that I should be looking out for. I was thinking of getting a Primair dueal Thermo/Fan speed Controller but from research i have done these are not so good for reducing noise and can damage the fans. I have also heard the Variab controllers may cause fires, is this correct?

    PS I'm running an RUK 315mm Centrifugal fan on the exhaust and a 250mm Spectrum fan for the inlet. The exhaust fan is running to baffle then onto a 300mmx1000mm Carbon filter so is very quiet hoever it's the inlet i would like to quieten down a tad.
  7. hXXp://

    That's the one that S&P recommends and sells. I have no idea what type it is though, so if anyone does please share.

    What's the update on the OP's S&P150?? I just bought one and am trying to decide the best choice.
  8. I have a 4" Active Air fan that I purchased with a speedster fan control. The humming noise from the speedster control was unbearable so I started to look for other solutions. After reading on the web for hours, I decided to try a 3 speed fan control. Man, what a difference it made. The hum sound is 95% gone for me and I can set my fan to High, Medium, or Low depending on my air flow needs.

    Here is what I installed: Shop Lutron 600-Watt White 3-Speed Slide Ceiling Fan Control at (if the link doesn't work search for "3 speed fan control"

    Since my fan was pre-wired to a grounded plug, I just opened the little box on the fan and wired the switch between the plug wire and fan connections, took about 5 minutes.

    Let me know if anyone wants more information.
  9. I have a 6 inxg y this j that will work for my fan I have same brand active air from.hyrofarm

    Sent from my XT907 using Grasscity Forum mobile app


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