fan speed control

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old shol4evr

Well-Known Member
borbor said:
Word.
major bummer with my setup, been trying to think of a way to work around it but can't really. Using a secret jardin DR90 (3x3x6) with a sun system lec 315 as the light. The ballast is built into that light, so it's like 20 pounds itself. The DR90 specs and stuff all say it can hold 65 pounds, but the filters I'm looking at are all around 45 pounds, so I'd be right on the limit which I wouldn't get close to doing in the first place, and since the filter is gonna pack on weight as it's used, hanging the filter in the tent seems like an absolute hellno, correct? Was gonna have it on a table next to the tent with about 3 feet of ducting up to the exhaust. I know that's not ideal but I'm working with what I have for now.

a decent sized tent will happen sometime this year for sure, as well as a light with a separate ballast, all in time.
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dude just go to home depot and buy some 3/4 in pvc and some fittings and build make shift frame to stabilize center support ,it will hold up.
 
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az2000

Well-Known Member
az2000 said:
It only costs $14 US and has some nice features like

  • Non-volatile memory so it remembers its settings after a power outage.
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Received my MH1210 and it doesn't retain settings after power outage. (The ad said it does.).

I'm going to look at one of the slightly more expensive STC-1000 or WillHi 7016 which control both heating and cooling. I don't need those features, but I suspect one of those has non-volatile memory. (I received my WillHi 8040 humidity controller. It has non-volatile memory. I posted initial experience with it in the harvest/cure forum. I assume the temp controller would have it too.).

Just wanted to post this update in case anyone reads my post and considers buying an MH1210. You definitely want non-volatile memory. It would be bad if a power outage occurred and the fan began coming on at 100 degrees (the factory default).
 
jijiandfarmgang

jijiandfarmgang

Well-Known Member
bravedave said:
Seems to be a fair amount of misinformation being bandied about there. Never heard of a motor "compensating" for low voltage. Also seems counter- intuitive to think rapid on/offs is healthier for ANY device than voltage reduction.

In any case, I saw nothing about a fire. Did see speculation about overheating and overstepping a variacs listed amperage but ...

That said I use a cheap boxwave one on my cheap inline fan and it is noisy. I would never use one on my hurricane exhaust.

@crawlintbss no worries friend. You provided some good stuff.
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The same user imnotcrazy in https://www.icmag.com/ic/showthread.php?t=117969&page=3

says this "Think, my fan pulls 0.7A @ 115Vac. Rated 87W reduce the Voltage by half the fan still requires 87W to drive the load. Like I said the speed reduction you see is due to loss of motor torque, therefore the fan spins slower. Just by reducing the voltage causes the first increase in current, but a motor will continue to pull more current trying to regain full speed as well as a loss in motor cooling by the fan running slower. The solid-state speed controls avoid these situations by removing the high current by completely removing the voltage supply every cycle (60Hz) the fan is still spinning and this time allows the motor windings to cool inbetween cycles moreson than the Variac type control."

I just had to try this out on a kill-a-watt, and its not true. The reduction in voltage causes a reduction in centrifugal fan speed, which also causes a reduction in amperage (reduction in total watts drawn.)

- Jiji
 
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az2000

Well-Known Member
jijiandfarmgang said:
I just had to try this out on a kill-a-watt, and its not true. The reduction in voltage causes a reduction in centrifugal fan speed, which also causes a reduction in amperage (reduction in total watts drawn.)
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Nice work. I just checked mine with a Kill-A-Watt and it shows different watts as a rotate the variac's dial (HydroFarm green centrifugal inline fan attached).

I've been thinking a variac may be overkill. If I use a thermostat to switch to full-speed (full voltage) when too warm, then all I need is a fixed voltage to run the fan at a speed sufficient to exchange the tent's volume every 5 minutes. That's about 40 volts using the Variac. I could buy a single step-down transformer to produce that constant voltage. Since I'm going to have a project box to contain the relay, thermostat and wiring, it wouldn't be bad to mount a transformer in there too. Just need to drill some ventilation holes in the box. Maybe use standoffs so the transformer has more air around it (if the project box isn't metal).

I mentioned exchanging the air every 5 minutes. I live in a dry climate and don't have to worry about humidity. If I did, I'd install a WillHi WH8040 humidity sensor to kick the fan into full speed. When either temperature or humidity gets too high the relay would be energized to switch the fan to wall voltage. Or, turn on a dehumidifier.
 
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avnewb

Well-Known Member
I need to design something to ajust fan speed with temps on hyper fan. I feel it will be fairly simple as it already has the speed controller but not finding any info yet on how that controller works. Possibly just need do build something that will ajust a 5v or 12v signal based on voltage but may be more complicated...

A simple option would just be to just get a second speed controller and set it to 50% and have a relay that switches to that speed controller when lights on using the timers or something and then back to the other speed controller set to 30% when lights off.

But something more elegant that adjusts speed based on temp would be ideal.

Anyone else have a hyper fan? Has this already been done? I searched and didnt find anything but have been following @az2000 build. Didnt think I'd have heat issues but hits 90s at 30% but stabilizes at 75 at 50%. However drops to 57 when lights off but that will not be an issue soon. Any thoughts?
 
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az2000

Well-Known Member
avnewb said:
A simple option would just be to just get a second speed controller and set it to 50% and have a relay that switches to that speed controller when lights on using the timers or something and then back to the other speed controller set to 30% when lights off.
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That's what I would do. Without knowing what kind of motor it is, you could damage it trying to use an inappropriate method/device. You could call Phresh to get some details about the motor, then google for information about that type of motor. (Probably an AC/DC brushless.).

But, I think the simplest thing would be to connect two speed controllers to a relay and switch between them based upon temperature or lights on.

There might be a way to use Arduino to generate the kind of signal(?) the speed controller makes. You could program it to follow the temperature.
 
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avnewb

Well-Known Member
Ya, I am sure there is a perfect way to do it but I do not have the skills. It may just be adjusting a voltage but without an oscilloscope I am not sure how the speed controller works. @ $23 for another speed controller I will just start with dual speed controllers set up to switch with the timer. Until I get it hooked up I guess I better leave it at 50% cause dont want it to get up to 90* again.

EDIT
the only thing I just realized is all the warnings about not disconnecting the speed controller with power on so switching between two speed controllers without shutting power off to fan may not be ideal. So if I go this route I think I need to be able to shut fan off, switch and then turn fan back on. Doable, but less simple...so may be worth seeing if there is a way to modulate the speed controller signal.
I could just use a servo to turn it based on temp or time too but that just seems more complex than it probably needs to be but again IDK what the speed controller signal is doing yet.
 
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avnewb

Well-Known Member
Also I don't think the signal that goes thru the speed controller actually powers fan because it works when controller is removed and circuit is open. Fan then defaults to 100%. Assuming this is true is why I think this fan could be really easy to control the speed.
 
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