# Fan speed controllers.... The 'cheap' versus those 'transformer' types (variacs?)...



## NewGrower2011 (Jan 20, 2012)

So can anyone break it down for me - the difference between using one versus the other? I know some basic electronics/priciples...

From what I gather the cheap ones are essentially just a variable resistor basically... like one of the light dimmers from the local hardware store. Right? That would be a DIY for a fan speed controller unless there's more inside those little plastic boxes that I'm not accounting for... The down-side to using a variable 'resistor' is that you're still using the electricity and rather converting it to - guess what - HEAT... right? Just what you need in your grow room... more heat... And you're not doing yourself a favor on the energy bill either... doh...

Then there's the expensive - but "right way" - to control speed of a motor which is through use of a transformer stepping the voltage down as opposed to 'restricting' the flow... which these things I've seen going for big bucks (surprisingly big) and so far I think only "CanFan" makes one for the hydro market specifically (?)... so I thought either they're meant to handle much more amperage and run several fans using 1 controller as opposed to the cheap ones being for one and only one fan... OR... they're a giant "variable" transformer... which I think I've found the real terminology outside of the hydro/grow world is a "variac" - correct me if I'm mistaken... All that copper winding doesn't help the cost of these obviously... 

If you know of good sources for these 'variable' ones that do it the "right way"... let me know... they weren't soley invented for our hobby so that means there's somewhere selling them without the inflated cost that comes with the association to a specialty/hobby market...


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## Gigaah (Jan 20, 2012)

I assume your talking about Large AC fans VS small 80mm 12vdc fans?


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## cannabineer (Jan 20, 2012)

I looked on variac.com ... the "complete" 10A variac, 120V in, 0-140 V out ... is like $360. Ouch.

However if your amp needs are low, and you don't mind building a chassis for it, here are small "bare" variacs designed for panel mounting, for cheaper. cn
http://www.iseincstore.com/variac-variable-transformersmall-120v-input-0-132v-output-single-phase.aspx


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## NewGrower2011 (Jan 21, 2012)

To be clearer... yes - I'm talking large AC fans... not those PC case fans which are DC based... god knows there's enough "fan speed controllers" offerings in the PC market...

Think the fan's you see on the hydro shops that are $100+ themselves... 400 cfm+ etc...


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## chis (Jan 21, 2012)

i have a 27 dollar fan speed controller and it workd great but i had to fine tune it over a week and still check it daily if you can control the temperature coming in and mantain good growingtemps they work i check my babies every day so i adjust as necessary. The most expensive ones have times on them and you can have your fan come on at set times the cheaper ones just stay one at the percentage you set it at. you could get a titian controler and run every thing from that.


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## jondamon (Jan 21, 2012)

The differences are that the standard Controllers cut the power on and off to the fan to regulate the speed thus starting and stopping your fan continously to the desired speed you want. 

A Variac speed controller regulates and reduces the amps/watts being delivered to your fan to control the speed. This way your fan is ON and the watts being delivered are less which causes your fan to run a slower speed. 


The standard speed controller can make fans hum quite loudly and can reduce the fans working life. 






J


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## everybodydoesit (Jan 22, 2012)

The following came from Growery.org. Seems to cover all the bases. Hope this helps.


[h=1]Fan Speed Control 101
[/h]Basic electrical methods for stealth fan oporation

[HR][/HR]

*Fan Speed Control 101*

*I. Know your fan*
In order to control fan speed, you have to know what type of motor your fan uses. Motors can be divided into two categories based on power source AC, and DC. AC fans are those you plug directly into a wall receptacle (Vortex, Dayton, Can-Fans), for more information about AC motors go to numeral II. DC motors are generally found in small fans like computer fans and rely on a DC power source like a rectifier (wall wart) or battery. For more information about DC fans, see numeral V.

AC fan:
 

DC fan:



*II. Know More About Your Fan*
AC fans use many types of motors but three types are important to us cabinet-bedroom size growers, *shaded pole induction motors*, *permanent-split capacitor (PSC) motors*, and *AC-DC Universal motors (Brushed Motors)*. For a list of motor type based on manufacturers, see numeral III. Shaded pole induction motors are simple single phase motors known for low starting torque and long duty cycles. PSC motors are also single phase motors but unlike shaded pole motors, PSC motors use a capacitor to help them start. AC-DC Universal motors are general purpose motors found in many household appliances like power drills and vacuum cleaners; their short service life makes them an unattractive option for fans. There are other types of AC motor that have been used for ventilation purposes, but aside from shaded pole, PSC, brushed motors, and three phase motors (which are beyond the scope of this course), ac motors are unable to be speed controlled without serious modification and/or risk. 
There are primarily two ways to control the speed of these motors, voltage control and frequency control; see numeral IV for more information.

*III. Fan Manufacturer List*
This information is relevant as of march 2009 but always be sure to double check by contacting your retailer or fan manufacturer! Using the wrong type of control with your equipment puts the fan and your controller at risk. This section is always in need of additions and corrections so if you have anything to add, post it or send me a P.M. and I'll be sure to include it.

*Permanent-Split Capacitor*
-Dayton squirrel cage blowers (Generally PSC motors, but they also make a shaded pole version)
-S&P Mix-Vent TD line
-Grainger squirrel cage fans

*Shaded Pole Motor*
-Vortex
-Can-Fan
-Valueline
-Elicent
-Active Air

*IV. AC Speed Control Methods*

*Voltage*
-Rheostat (Old dimmer switches): Poor choice, excess power converted to heat.


-Triac (New dimmer switches): Poor choice, inherent problems with triac controls risk fan lifespan.


-Triac w/ Snubber circuit (Fan speed controllers, Solid state controllers): Good choice, snubber circuit removes most of the risk to the fan. Still not the best because it can cause some motors to hum.


-Capacitance level control (No hum fan speed controllers, 3 speed controllers): Good choice, only limited by the discrete speed choices, no infinite control.


-Variable autotransformer (Variac): Better choice, continuous sine wave of a lower voltage (unlike a triac which chops up the sine wave to acheive a decreased voltage) allows fan operation with no hum.



*Frequency*
-Varable Frequency Drives (VFD, AFD): Best choice, complex circuitry senses changes in the motor allowing it to vary frequency of the AC source as well as the voltage which maintains a constant torque, unlike voltage regulation.


*V. DC Speed Control Methods*
DC speed control is much simpler than AC speed control. In order to lower the speed of a DC motor we must lower the voltage, this is accomplished in various ways. Linear voltage regulation relies on resistors, and diodes to remove the excess voltage as heat. Pulse Width Modulation sends bursts of energy to the fan and the averaging effect results in a lower net voltage and reduced energy use.


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## FootClan (Jan 22, 2012)

Yes ive been saying the same thing for 2 years now.......Even people at hydro stores dont understand that you are still using the same amout of PG&e when you slow the fan down and the extra power is disapated off..... Ive been telling people this for long time now and i still see people telling other people that if you turn down the fan you use less energy finilly somone on here talking about how it DOSENT reduce power cost and creates more heat.... Plus rep for you sir!!


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## Mr.Therapy Man 2 (Jan 22, 2012)

Speedster controls will burn your house down,buy one that cost a little more cash,its worth the piece of mind,my speedster just would not kick on some mornings so when I smelled shit getting hot I knew my fans did not kick on,I got rid of those in about 3 days and that was 3 days late in my book,theres nothing worth burning your household memories and belongings for life.over 50 dollars..


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## NewGrower2011 (Jan 22, 2012)

So can anyone make actual product reccomendations? Let's start with the not so obvious and skip the $30 speedster nonsense.... what real products can we source? I'm thinking the industrial sector should
offer something with the "hydro" association driving up costs like I mentioned... Hell even if the markup isn't toooo bad - where can I find something I can order.... soon... 

I'll take a few of those terms from that Growery post and see what I can dig up...


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## Hotwired (Jan 22, 2012)

lol good thread

I use my old speedsters as on/off switches. Better than pulling the cord out every time I need to turn it off.

Hopefully someone is using a decent variac to recommend to us.


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## NewGrower2011 (Jan 23, 2012)

Okay folks. Trolling around on other forums I found a link - and it was actually still valid!

http://www.circuitspecialists.com/variac-variable-ac-ps05kva.html

Not much more than a Speedster... I think I'll be ordering one real soon... Anyone able to confirm this is the right thing? Seems it...


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## PlantManBee (Nov 15, 2012)

Wow! I've been looking for this! Thanks for the link because the can-fan brand is like $200 bucks locally. The hydro shop guy just looked at me like I was crazy when I brought up the heat generated by the speedster type. I'm going top spend the extra cash.


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## ASMALLVOICE (Nov 16, 2012)

Greetings All,

I just received my speed controller for my extraction fans. It is a single phase vfd with onboard loop and/or remote input control. I got this on clearance at Graingers. $240(open box but unused), regular price $475. I can configure it to go 120 or 240 ( internal jumpers ) and has 12 amp capacity. This will allow me to dial in on the exact flow needed to maintain an ever so slight negative pressure or do rapid air exchanges ( scrubbing ). They have a ton of them, that are between 3-500 bucks, and will easily accomodate up to a 12 amp fan, be it 10" or maybe 12".




If fine tuning air flow with as little motor hum as possible, these are the medicine for that pain. These are far superior to any "resistive" manual controller.

Peace

Asmallvoice


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## NewGrower2011 (Nov 16, 2012)

Glad you found those... I've still not made a purchase here, but I did see Grainger has a lot of gear that might be useful (i.e. cycle timers)... I need to dig around their site a bit more...


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## berkman858 (Nov 18, 2012)

NewGrower2011 said:


> So can anyone break it down for me - the difference between using one versus the other? I know some basic electronics/priciples...
> 
> From what I gather the cheap ones are essentially just a variable resistor basically... like one of the light dimmers from the local hardware store. Right? That would be a DIY for a fan speed controller unless there's more inside those little plastic boxes that I'm not accounting for... The down-side to using a variable 'resistor' is that you're still using the electricity and rather converting it to - guess what - HEAT... right? Just what you need in your grow room... more heat... And you're not doing yourself a favor on the energy bill either... doh...
> 
> ...


I have (5) 6" Max-Fans and they come with built in speed controllers. Just thought I would throw that option out there.

P.S. - no hum at any speed.


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## Tripped circuits (Nov 20, 2012)

if you run your fan with the controller that slows it down you are wasting electricity. Fans are made to run at an efficient speed. You would be better with a full on switched to a full off. Simple for two reasons, less wear and tear on the fan windings/bearings/stator and magnets. secondly if you run something more efficiently it costs less to run per work performed. just my little tid bit


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## acellular (Jul 16, 2013)

So it seems like the variac is the best for fans. There's a 5 amp on ebay for $65 delivered. So what can i use my Speedster on effectively? Does it work good on ecoplus water pumps? I'm gonna swap out my Speedster for the variac because my fans do hum pretty bad when dimmed down. I just want to know what will my Speedster work good on, anything?


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## jijiandfarmgang (Jul 16, 2013)

acellular said:


> So it seems like the variac is the best for fans. There's a 5 amp on ebay for $65 delivered. So what can i use my Speedster on effectively? Does it work good on ecoplus water pumps? I'm gonna swap out my Speedster for the variac because my fans do hum pretty bad when dimmed down. I just want to know what will my Speedster work good on, anything?


 You can use it on what it was designed to be used on "For use with brush type motors only."


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## FuckJeffGoldbloom (Jul 16, 2013)

then what do you suggest?


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## famine (Jul 16, 2013)

NewGrower2011 said:


> So can anyone make actual product reccomendations? Let's start with the not so obvious and skip the $30 speedster nonsense.... what real products can we source? I'm thinking the industrial sector should
> offer something with the "hydro" association driving up costs like I mentioned... Hell even if the markup isn't toooo bad - where can I find something I can order.... soon...
> 
> I'll take a few of those terms from that Growery post and see what I can dig up...


I am actually in the market for a Titan Controls Mercury 4.
I just upgraded to an 8" Fan and it is sucking all of the Air Conditioned air out of my home and it can't keep up in this heat wave.

The unit comes with a temperature control that ramps up the the fan speed as the temps go further from the setpoint.
It also has a minimum "idle" setting so that it still will maintain negative pressure on the room. Rather than just an on or off control.
While my lights are off (during the day) the fan should just run in idle mode, when the lights kick on and temps start to rise the fan will be turned up to full power.
I figure it should pay for itself in a month or two.

If anyone has any experience with them I would love to hear your feedback.

http://www.titancontrols.net/products/ventilation/mercury-4.aspx


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## acellular (Aug 27, 2013)

Do not buy that! I bought this on ebay for $65 landed and I love it! [h=1]5 AMP 110V VARIAC AUTOTRANSFORMER VOLTAGE REGULATOR POWERSTAT 0-130V OUTPUT NEW[/h]


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## famine (Aug 27, 2013)

Actually I did buy it. Or the same item from a Canadian manufacturer.
Very happy with it.
http://www.grozonecontrol.com/distributors.html


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## dr.medecine (Jun 19, 2014)

Thanks, humming noise is killing me on my primaklima GSE 125mm (400m3) fan at home, guess I better invest in a proper controller for it


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## dr.medecine (Nov 4, 2016)

This is a few years ago but forgot about it for some reason and not been here for a while haha..

Anyways just in case someone else experiencing the same issue I had, trying to use cheapo electronic controllers for the fan and having a nervous breakdown cause of the noise they make (yes I live small and sleep not that far away from the fan) I though I provide some updating after close to 2 year running a proper variable auto-transformer and went for the smallest model I could find cause just controlling a single 125mm fan, still a klima but the straight forward vanilla model.

Contacted Primaklima with a problem trying to glue a housing with minor damage asking for the right glue, they responded by sending me a brand new housing free of charge, but it did not stop there they asked me what new fan I wanted too, yeah they did send out a fan + a new housing for my old motor/blades no questions asked and led me choose model so how could I possible abuse such a fantastic offer and kindness by asking for more than I already had like for example asking for a big "pro" blue line or similar haha? I.m not that greedy and appreciate the kindness very much, please conciser Primaklima if you want heavenly service guys? My warranty was out too, they did not even ask for express shipping fee when sending me a mini pallet with 2 boxes well wrapped, amazing.

Since the tent I run this one in is so tiny I can run that 125mm as basically walking speed and cannot hear it some meters away at all ,absolutely not a single irritating electric noise whatsoever form cheapo solutions like I used to try to get working. Tufvasson OIEA 1 the variac is called and find some Swedish site: http://www.tufvassons.se/produkter/test-1

 

If you experiencing the same irritating noises I did and run a somewhat quiet fan at low speeds so that nasty sine wave buzzing this is the solution, no competition whatsoever this is truly dead quiet, highly recommend and a one time cost. This is their smallest and 230VAC 1A rated, not much really but also can be put in my hand and more than enough to drive a standard fan.


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## ismann (Nov 5, 2016)

I'm using a $20 speed controller with an iPower 6" blower and the buzz is certainly there at any setting below 75% or so. I keep it around 75% anyway for my 2x2x4'.


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## coreywebster (Jan 20, 2017)

dr.medecine said:


> This is a few years ago but forgot about it for some reason and not been here for a while haha..
> 
> Anyways just in case someone else experiencing the same issue I had, trying to use cheapo electronic controllers for the fan and having a nervous breakdown cause of the noise they make (yes I live small and sleep not that far away from the fan) I though I provide some updating after close to 2 year running a proper variable auto-transformer and went for the smallest model I could find cause just controlling a single 125mm fan, still a klima but the straight forward vanilla model.
> 
> ...


Ah that's nice to hear.
I have just ordered a 1.5amp variac for my 8" fan.
Had my grow room down for 9 months but had it running 5years previous to that, Did lots of sound proofing for peace of mind in that time and the only thing that still exists is that bloody hum. 
No amount of sound proofing will work for that type of frequency beyond huge amounts of mass which is just not possible.
Anyway rooms back in action and that hum is driving me crazy, it didn't bother me all those years because I didn't have neighbours to worry about, that changed.
Now I just have to wait for the variac to be delivered so I can cut off the old crap speed controller.
I'm feeling a bit more reassured now I have read your post.


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## Lurrabq (Jan 20, 2017)

coreywebster said:


> Ah that's nice to hear.
> I have just ordered a 1.5amp variac for my 8" fan.
> Had my grow room down for 9 months but had it running 5years previous to that, Did lots of sound proofing for peace of mind in that time and the only thing that still exists is that bloody hum.
> No amount of sound proofing will work for that type of frequency beyond huge amounts of mass which is just not possible.
> ...


If you are running an 8" fan, that amp rating is a little low. That's only 180W. Not much room for the surge when you start the fan. 

This all is assuming you're running at 120V.


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## coreywebster (Jan 21, 2017)

Lurrabq said:


> If you are running an 8" fan, that amp rating is a little low. That's only 180W. Not much room for the surge when you start the fan.
> 
> This all is assuming you're running at 120V.


Yeah I thought that when I saw what other people were running so I double checked.
But My power is 240v
Here's the stats
*200mm ISOMAX 3-Speed Fan Specifications:*

Airflow - 570/770/870mtr3 per hr

Current - 0.36/0.4/0.6 amps

Power consumption - up to 128 watts

Full diameter: 260mm

Length = 680mm

Weight - 7.7kg

Noise level - 55db

The 1.5amp Variac is good for 345w apparently.
Its a good fan overall, ran the first 3 years 24/7 then I started turning it off during feed time for next 2 years. Its just the stupid speed controller that's the problem. I probably could go to a 6" these days but I used to run it filter>fan>cooltube>cooltube>cooltube>outside when I ran HPS.
The fans come without speed controller too but this one its on the wire, I assume I can just cut it off and rewire when the variac arrives.


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## 2Ton (Jan 22, 2017)

I use a mid range controller that cost £80, it is analogue but has never missed a beat and keeps the temps in order! I use a 12" inline outake and a 10" inline intake! The main reason i use this system is the heat doesnt spike like some systems... the controller just fires up the extraction and all is well and iam running 4000w.... look. https://www.rollitup.org/attachments/20161121_152502-jpg.3836403/


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## cookie master (Jan 25, 2017)

buy a 1960s era variac off ebay.


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## dr.medecine (Feb 12, 2017)

coreywebster said:


> Ah that's nice to hear.
> I have just ordered a 1.5amp variac for my 8" fan.
> Had my grow room down for 9 months but had it running 5years previous to that, Did lots of sound proofing for peace of mind in that time and the only thing that still exists is that bloody hum.
> No amount of sound proofing will work for that type of frequency beyond huge amounts of mass which is just not possible.
> ...


Sorry did not see until now, do not log in very often these days especially since not growing MJ anymore (or at least on hold for some time), still grow vegetables and weird plants in general cause it's addictive just caring for a garden..  Yeah I know about the trouble and it sucks, a proper variable transformer is the way to go for sure. I run my 5"/125mm at such low speeds where I ca no longer even physically her the fan blades move, must stand close to feel/hear air move, first few days it was surreal felt like a impossible equation cause even at lower speeds (cheap electronic sine wave control whether added or from factory) there's noises that just blend and hard to separate every source at times, with this solution and truly low rpm's it's like all noise just gone and like I said I run mine so darn slow I must stand next to it to hear anything from the fan and what I hear is just the air. Sounds very clean, like I said surreal. Good for you you took the decision to go down that route, hope you are happy with your new transformer.

Every space I set up from here on where noise must be reduced will contain a oversized fan of decent or better yet high quality with a a proper design, bearings then add the variable autotransformer to step down voltage and run fan slow instead, cost more but if budget will allow it? 



cookie master said:


> buy a 1960s era variac off ebay.


Yeah especially you guys who live in the US have got some golden opportunities cause most for sale seem to be there, shipping alone will defeat the value/$ for rest of us, these little suckers very effective but also heavy especially when you need a large one.


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## dandyrandy (Feb 12, 2017)

I've used a triac speed controller on a fan for ~5 years. No issues with either. It is true that a solid state controller can make some fans hum and actually create rfi. But so does a brush type AC motor which most are. On the plus side if you find those as negatives a well designed triac controller is much more efficient than a Variac. ymmv


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