How can I make a AC fan speed controller?

[Ekko]

Just what it says in the title. In my grow cabinet I am using an old air hockey fan. The cfm is approximately 95. The fan is VERY loud and I NEED this grow to be ultra stealth, the fan gives it away. I was thinking of just using one of those AC fan speed controller you can find on ebay and amazon for $20 (Amazon.com: Variable Fan Speed Controller). The problem is that where I live the cheapest one I can find is $75!!! It's crazy expensive for something that seems so simple.

SO my main question: is there a way I can SAFELY make a fan speed controller that is cheaper and with out the risk of a fire? Or should I just spend $75 on one?

I can't just by a cheap one from America or china as they use different wall plugs to what we have here in New Zealand. It also costs $40 to ship a $40 controller from Australia so $80..

 

[keefy69]

If money is an issue start with ebay searching for "220v speed controller" the prices vary from really cheap to more expensive, as for the wall plug issue, you can get adapter for your NZ plugs, but you should be carefull that the controller supports the voltage you have. More details on the motor would be nice too as not all motors play nice with these kind of controllers.

 

[Ekko]

If money is an issue start with ebay searching for "220v speed controller" the prices vary from really cheap to more expensive, as for the wall plug issue, you can get adapter for your NZ plugs, but you should be carefull that the controller supports the voltage you have. More details on the motor would be nice too as not all motors play nice with these kind of controllers.

Thank you so much for the help. The fan motor is a bearing fan and not brushless hence why it is so dam loud. It says 0.20amps and 50~60z (herts). And the fan is standard 120mm but very thick.

 

[michiganrules]

What about a dimmer switch for lights

 

[SewStoned]

What about a dimmer switch for lights

Michiganrules has it right. Take an extension cord, cut off the end you plug things into, peel back some rubber to expose raw wire on the positive and negative wires. Open your dimmer switch w. A plugin (7$ at a hardware store maybe) and twist the negative wire on it with the negative wire on the cord. Use a marrett ($0.08 at home depot each) and twist that over the joined wires to connect them and prevent fires. Repeat this last step for the positve wires on the cord and dimmer switch. You can buy plastic casings to house it all in from the electrical department of your hardware store, same place you found the switch and marrets. Lots of yputube video's on it. Ill post a pic of mine when I get home.

 

[IndigoBreeze]

Any AC fan is too loud for a stealth grow. Work with computer case/processor fans. I usually yank out the AC motor and fan on a duct boosting unit and just silicon glue in the 12v computer fan. 12v plug transformers are being throw away by the millions so they are easy to come by. They also make speed controls for the 12v computer fans and I use them where needed to dial any noise down to zero.

 

[IndigoBreeze]

What about a dimmer switch for lights

Never with a motor.

 

[NinaSoma]

Which one is more expensive, buy or make?

 

[Southwards]

Just in case it isn't clear at this point, normal dimmers are NOT safe AT ALL to use on an ac fan. What you are doing if you put a resistance in series with a coil is analogous to holding the fan blade back with your hand. The circuit will draw more current and can become a fire hazard.
If you absolutely must slow that fan down then purchase a proper ac fan controller, OR make one yourself, here are the schematics of an ac fan controller:
AC Motor Speed Controller Circuit
It is not as hard as it looks, and can be a good learning opportunity, any run of the mill electronics shop probably has everything you need, it shouldn't be expensive to make at all and requires only minimal tools.
Alternatively just purchase a fan with lower rpms
Hope this clears up any doubts, it has been some time since the original poster asked but perhaps someone really thougth a dimmer was the way to go.

 

[TheEEngineer]

The responses saying not to use a normal dimmer is absolutely correct. Normal dimmers are meant to work on a nearly pure resistive load, which is not a motor by any means, you have complex components of impedance caused by both capacitance and inductance seen within the model of a motor. Motors are typically best run at either full speed or the use of a VFD which slows the motor by reducing the frequency at which the drive will operate instead of just throwing a resistor in front of the load thereby reducing the current available to the motor.

While a VFD seems a bit overkill an important note is that quite a few new air conditioner units have what is called an inverter that is capable of running the compressor at varying speeds leading to an overall more efficient design.

I realize that I went a bit off topic but I felt that an explanation of why you cannot just use a dimmer for an air conditioner is important.

 

[BeccaBuds]

Velleman makes a kit that will work for you. Velleman K2636

 

[AdaminCO]

Velleman makes a kit that will work for you. Velleman K2636

I think you just woke up the oldest thread I’ve ever seen woke up before. Lol!

 

[BeccaBuds]

Yea, I didn't notice the date until after I clicked "Post". Oh well, better late than never, lol!

 

[AdaminCO]

Yea, I didn't notice the date until after I clicked "Post". Oh well, better late than never, lol!

It’s happened to all of us. Lol!