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Max Fan speed control

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outdoorbrah

New member
Hey guys, I'm having some trouble with my carbon filter and fan speeds. Hopefully I can get some input here.

I recently purchased a 6" Max Can Fan
http://canfilters.com/max_fan_6.html
to go along with my 440 CFM carbon filter

I didn't realize that the lowest setting on the fan was 200cfm, which is much to high for my 45cf grow tent. Air is being pulled through the carbon filter too quickly and odor is not being eliminated. Thankfully I'm not in flower, but the problem needs to be fixed asap.

I was about to purchase a speed controller for the fan, but saw that the controllers are only for brush type motors, which my max fan is not. (Furthermore the company FAQ says the fan can't be turned down below 40% at all or it will shut down)

They make a recommendation of their website to purchase the a variable speed controller, but they cost nearly $250.

Is there anything I can do to slow this fan down a little more? I opted for the more expensive fan because it had the built in speed controller, but it's looking like I may need to purchase a different fan.

Thanks for any help
 
B

Bobbito Blaze

Member
I have the same fan 6" hi out put I went to my local pawn shop an in the bargin bin I found a router var. speed control for $8 they sell them at harbor freight also fairly cheap. And it works great no issues been that way for 3 months now running all day. An works on all settings
 
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outdoorbrah

New member
Thanks for the quick responses.
I was turned off purchasing one of those speed controllers because they all state that they are for brush type motors and can cause damage to other motor types. I also read reports of the controllers heating up when used with non-brush type motors.

I'm glad to hear that some of you have had success using them with this fan. I suppose I will go pick one up tomorrow. Thanks guys.
 
Coconutz

Coconutz

Active member
Veteran
I had an 8" maxfan, but it wasnt a variable speed. I tried to use a speedster to reduce it and it growled and sounded like it was fucked up. I took it down and just used my vortex. They work fine on a speedster.
 
rangergord

rangergord

Active member
I love my maxfan but it is the right size for my closet. Canfan should make a 4" max fan in my estimation. The maxfans are a mixed flow design that excells at moving air through the ducts better than regular turbo fans, plus it is quiet and very energy efficient and delivered at a great price. So why not a 4 incher for those people with smaller grows? I think the built in speed control is a great thing and I don't know anything about the compatibility of other speed controls. Is a bigger carbon filter an option? Not likely I guess in 45 cf and most filters are the same price as another blower. Restricting the airflow into the max fan may help. It may quiet it down some too.
 
CannaBunkerMan

CannaBunkerMan

Enormous Member
Veteran
What you're looking for is a solid state dimmer switch. The electronics in most dimmers won't play will with a fan.
 
CannaBunkerMan

CannaBunkerMan

Enormous Member
Veteran
Found a good article on this for you:

http://www.fancollectors.org/info/speed.htm


Slowing Fans Down


By John McComas

--------------------------------------------------------------------------------




I would like to emphasize a point about dimmers...
Do NOT use a light dimmer for a fan.
PLEASE spend the extra couple of bucks for a real "fan" speed control.
>>>> There are differences! <<<<<



--------------------------------------------------------------------------------


LIGHT DIMMER: $ 5-10
(Solid state phase angle firing of a triac) It can be a rotary switch or a push-off, push-on type, or slider. The push switch type can be turned on at low. (may not run a fan motor properly) The rotary type switches on at low and increases to bright. (same problem, may not trigger properly Does NOT have a minimum level adjustment control. (This is a very important feature)
OK, so what's this "may not run a fan motor properly" hoopla?? Without getting into more theory than you would probably want to know, suffice it to say that solid state controls are real sensitive to line voltage and differences in load variations. If the voltage jumps around because of the air conditioner kicking on, etc. or flipping on or off a lamp on the same branch circuit. It may cause the dimmer to kick off, or worse, half cycle which sends half wave rectified DC to your AC motor....Not Good...Toast. (Ever notice how they say on the package "for incandescent use only"?) (Light bulbs don't care what you feed them they just average the power)

When you start a dimmer on high, then reduce the speed, you can go to a lower setting, than if you started the dimmer at the lowest setting and increased it slowly, it would start running abruptly at a higher speed. It's kind of like the flywheel effect in that the motor windings kick some voltage back to the dimmer that helps to keep "triggering" it. (If that makes any sense.) If the motor is not running initially, it takes more to trigger it.

Bottom line is DON'T use a light dimmer to control a fan.



FAN DIMMER, or ELECTRONIC FAN SPEED CONTROL: $ 10-20
(Solid state phase angle firing of a triac with additional needed components for inductive load (motor) operation) I've seen them with a rotary switch or a slider control. They always turn on at high speed and then adjust to slow. Good ones have a minimum speed adjustment. (If they don't have a min. speed adjustment they don't go very slow.) (Get one with a user settable minimum speed adjustment) No solid state dimmer operates real well at real low speeds. Fan dimmer type speed controls are usually rated about 5 amps. Did I say to get one with a minimum speed adjustment??? These controls are quite efficient.


DE-HUMMER CONTROL: $10-15
These are actually a selector switch with a bank of AC capacitors that are placed in combinations of series and parallel circuits to vary the capacitance in series with the fan motor. This results in slowing the fan down by limiting the current to the motor with different values of capacitance. They usually have about four speed settings. All the capacitor type controls I've seen are rated at 1.5 amps. They seem to work well for ceiling fans, but may only work well for 8, 10, and maybe 12" desk fans. (depends on motor, etc.) The capacitance values in the de-hummer and the motor must be pretty well matched to get the results you desire.... (They were made for ceiling fan motors with lots of poles and momentum) Too small a capacitance and motor might not start turning on its own. Too much cap. and fan runs too fast at the controls lowest setting. Too big, or powerful a motor, and maybe only one or two slower speeds will keep fan running. A too small, efficient motor and maybe the lowest speed is still too fast. A capacitor type control is very efficient if properly matched to the motor.


RHEOSTAT: $20-100
Rheostats need to be fairly large and give off heat and need to be mounted in some sort of enclosure to allow heat to escape. They are made by winding nichrome wire around a round ceramic form. They have a knob adjustment that slides a carbon brush over the nichrome to adjust the resistance. The rheostat consumes the energy not diverted to the motor and gives off the energy in the form of heat. The power used to run the motor at high speed is the same amount used at low speed except now the rheostat gets hot. Rheostats must get sized bigger for more powerful motors. Rheostats are rated in ohms and watts and need to be sized for the motor you want to control. Rheostats are not readily available anymore, and not recommended except for ones that were bought with the fan they were made to control. Rheostats are the least efficient control.


VARIAC, POWERSTAT, VARIABLE AUTOTRANSFORMER: $40-100
Variacs, Powerstats (brand names) are actually a variable autotransformer. They are made by wrapping copper wire around a laminated steel donut. They have a knob adjustment that slides a carbon brush over the transformer winding that gives an output voltage from 0 to 140 volts AC. Just like the extra 20 volt boost (140 volt) certain models can be wired for 120 volt input and 0 through 280 volt output. (Like a step-up transformer) Variacs are heavy and usually sit on a table or floor. They are sized for the voltages they will be used for and how many amps they can supply. The smallest ones are about the size of your fist and handle 1 amp loads. The larger ones can be as large as a basketball, weigh 80 pounds and can handle 30 amp loads. I would recommend one with a 3 to 10 amp capacity based on what you can get for the price. New Variacs can cost $200+ but used ones average about $50. Variacs are very efficient.


IN SUMMARY:
A Variac will give you the best consistent results controlling fan speeds for all fan types, but they are large and heavy, cost about $50 used. The next best thing is a fan dimmer, or speed control meant for use with fans and has a minimum speed adjustment. They cost about $10 Next would be a capacitor type "de-hummer" control and it gives you about 3 usable speeds, if the control & fan are matched. Cost about $10.
I hope this information helps.
John McComas
 
R

Rolldaddy

Member
I also have a canfan that comes with 3 setting but I would like to run it slower that the lowest setting. I am also confused about which dimmers can work with which motors

Will someone please post a link to a switch I can order to connect to my canfan?

Thanks in advance for taking your time to point me in the rite direction
 
C

Conformist

You must be doing something wrong.

I have a 3x3 tent, 440cfm 6" can fan HO exhaust dimmed down to 300cfm with a 326cfm 6" Mountain Air filter and there's absolutely zero smell.
I have tested it many times before, i even smoked 3x 1 Gram joints in a row in there once and my girlfriend couldn't smell a thing outside.
 
Fly by Night

Fly by Night

Like a Wing
Veteran
6in vortex, full tilt... Peace!

picture.php
 
R

Rolldaddy

Member
What up Fly By? Nice pic.

I have the 6 canfan which I bought would be perfect since it came with a built in switch for 3 speeds but even on speed 1 it's going faster than I'd like. I even looped the exhaust duct and put some bends in it to try and slow down the airflow a bit but it's still too fast.


I'm using it in a sealed room that has ac and co2. So I just want the fan pulling thru the filter as slow as possible, just enough to keep a little bit of negative air pressure in the room so that it will only smell inside the room. How it currently is no smell escapes. But if I could slow it down a bit I wouldn't waste as much co2 or my cooled air. Plus it will let me control my RH better.

Since I'm no expert with electricity, and electric motors I'm trying to figure out the best way to accomplish slowing down my fan a bit. I appreciate the link Frank posted for me but I'd like to know if the one I posted the link of will also work?

Thanks
 
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