Vortex inline question.

[przcvctm]

My cab is small, about 20 cubic ft.. When I designed it, I went with the larger fan/ lower rpm philosophy for quiet stealth. I want to replace my 6" Fantech with a 6" Vortex. The Fantech came with a min./max. set screw which I was able to use to run it on low speed without an external controller.

Does the Vortex come with a similar function?

Edit_My memory is lousy. Today I took the front plate off the wiring housing of the fan and guess what, no min/max set screw. Then I took the face off that blue, solid state speed control that is usually sold with Fantechs, and there it was. Apparently the set screw is a sort of macro adjustment and the dial outside adjusted the speed of the fan within the range set by the set screw. For my cab, I had both set at the slowest and it worked well for my small cab. Sorry for the thread about nothing.

 

[Mr. Bongjangles]

Unfortunately I can't answer your question definitively.

I did look through the instruction manual on my 6'' Vortex, but it doesn't mention a low speed setting. Mostly about the mounting instructions and warranty/safety stuff though.

Here's a pic of the wiring diagram, perhaps this might answer the question for someone who understands this stuff more than me hehe:

 

[DangerP]

There isn't a low speed setting, but you can buy a third party device that lets you control it (it's basically just a cheap veriac). The problem I've had with this is that while the overall noise from the fan is reduced, you get a high pitched whine that I find to be a lot more noticeable than regular fan noise.

Why do you want to throttle the fan?

 

[przcvctm]

Why do you want to throttle the fan?

I don't. As I mentioned above, I designed the cab to be vented by an over-sized fan running at low rpm rather than a small fan running fast and making more noise.

The Fantech I have had for the last four years can be manually set to run at it's minimum rpm. I was looking into a Vortex because the workmanship of the Fantech wasn't that great when I got it. I had to caulk with epoxy and duct tape the center housing seam because it had gaps most of the way around that would have allowed dank cab air to escape before the carbon filter.

If the Vortex just runs at 449 cfm when plugged in, then I'll have to look for another brand. I don't think I need my cab air exchanged 22.45 times/min. with all the motor noise that I suspect would go along with it.

 

[hurricane]

Danger P mentioned getting a cheap speed controller that produces a whine, but there is no need as you can get a real variac that will produce no whine for about $50. The difference is a basic speed controller turns the power on and off fairly quickly to make it slow down(choppy power) and the variac will use the properties of wound copper wire to reduce to reduce the voltage(very smooth). Most any high end fan will require an external speed controller unless it was designed specifically for the grow room(and will then cost more $$$ or less quality). It apears you've already seen the quality of "made for growers" stuff Try a vortex or elicent which are designed for more industrial applications.


hurricane

 

[Budweiser13]

Has anyone actually used a variac long term to control the speed of there inline fan. I have heard conflicting information that states variacs can ruin your inline fan. So are variacs safe for inlines or do they shorten the life of the fan...

 

[Hawk]

http://www.plantlightinghydroponics.com/fan-controls-c-76_413.html

So are you saying the 20 dollar Fantech & Cap speed controllers ^ sold in this link are not "smooth" at reducing speed ?



Thanx

I have one of those. Makes my 6" EcoPlus really noisy.

Those types of controllers use low frequency pulse width modulation to control the fan speed. They basically supply power in pulses. The fan motor is either on or off but it happens so fast it's not like than fan is herky-jerky or anything. The fan rpm is variable and "smooth" by doing this switching. However, it can cause the electric motor's commutator to vibrate. The commutator is the device that momentarily reverses the current inside the motor. All that on/off switching can make commutators really wale. Mine was especially bad at certain fan speeds.

I suspect commutator noise can be more or less depending on the size and specifics of the fan motor.

 

[przcvctm]

I appreciate the problem solving contributions. I'm going to assume that the manual speed setting is unique to Fantechs.

I think from the discussion, you can see a manual minimum setting on a larger fan is preferable if quiet is the objective.

Maybe the FG series is constructed better than the FX it replaced.

 

[hurricane]

Has anyone actually used a variac long term to control the speed of there inline fan. I have heard conflicting information that states variacs can ruin your inline fan. So are variacs safe for inlines or do they shorten the life of the fan...

I've no degree in electronics, just a simple hobyist. But i believe what you are speaking of is whats is summed in this quote:

http://www.eng-tips.com/viewthread.cfm?qid=200189&page=10

Speed of an AC motor is ALWAYS determined by the supply frequency and the number of poles in the motor winding.

Changing the voltage without changing the frequency reduces the TORQUE of an AC motor by the square of the voltage. So for instance at 60% voltage, the torque is .6 x .6 = 36% of the normal torque. If you have a fixed load, the speed reduces because the motor now has insufficient torque to keep it spinning at full speed. DEPENDING ON THE MOTOR DESIGN, that may or may not work out too well, because MOST AC motors will try to keep running the same speed and pull more current to do it, until the motor burns up.

A variac or rheostat (a.k.a. dimmer) can change the speed on SOME TYPES of motors because they have a type of design that inherently limits the current flow, thus allowing the lower torque output to occur without burning themselves up. These are called Shaded Pole motors and most likely your fan is one of these if it hasn't burned up from your test. Another type is a "Universal Motor" which is really more of a DC motor to which you supply AC. This is what you find in small appliances and portable tools, not likely on a fan.

I've used a variac previously on an elicent 150A, but i am growing smaller than before and only use a stanley blower for exaust atm which has 3 speed settings built in. If a variac works for you or not may depend on the manufacturer of your fan, and the type of motor they use.

Another great option, at least for elicent fans, is the elicent transformer based speed controllers.http://elicent.it/inglese/sensor.html Unfortunatly these are not available in the states. I tried talking to elicent in italy, but they forwarded me to their american counterpart, who kept ignoring my questions about transormer based speed controllers and suggesting a speed controller i already have that makes the motor buzz.

And a special thanks to hawk for explaining what exactly is going on in the regular speed controllers.

hurricane