Fan Speed Controller

[MedicMan613]

Hey all,

Just putting a feeler out to see what everyone is using for fan control. I understand that the Variac is an option but very expensive appx. $140 CAN. What else are people using? I know that the light dimmer is an option, although unreliable. I am specifically looking for options that make fan speed quantifiable for repetition.

Thanks for the help and happy roasting.

MedicMan

[SusanJoM]

This is the one which GregR has recommended since the get-go. 
https://www.amazon.com/Speedster-Variable-Speed-Control-Sprayer/dp/B000HQAVNI

[SusanJoM]

Well I have taken the Variac totally out of the loop and incorporated the controller I linked above. 
It is so much easier than dealing with a Variac. 
It is so much cheaper than a Variac. 

I wouldn't recommend a Variac to a new buyer again....

[trumz]

I got myself one of these

https://www.aliexpress.com/item/AC-220V-10000W-SCR-Voltage-Regulator-Speed-Control-Dimming-Dimmers-Thermostat-free-shipping/32323041235.html?spm=2114.13010608.0.0.DQ0Aji

Hoping I could rely on the number display to give repeatable set points, but the whole unit doesn't work very well.  For example, if I set it to "40" which gives me a nice med-slow fan speed, the fan will ever so slowly SLOW DOWN to a crawl without changing the setting.  Also, while testing with multimeter, I see high volatges throughout the range, but the fan still speeds up and slows down somewhat.

I DON'T recommend

I'm back using a standard cheap dimmer for now.

[edtbjon]

If memory serves me, Canada has 230V for AC. The router speed controller which Susan linked is a good choice, but do check the specs for the input current. While the Variac (with its 4 inch dial down to single % value control) is overkill, you do need decent precision to find and mark out say three settings. The thing is to be able to easily repeat these settings.
About the chinese controller which Trumz links to, I guess it's a simple light controller with a "voltage" indicator on it. I.e it doesn't really change the voltage, but rather the frequency. That works well with a light bulb and some other applications, but obviously not for precision control of a heavy duty fan. (It's like "been there, done that"... I do have a few light bulb controllers in the cupboard from early experiments with fan contol. )

[Brent]

Canada is 120 v 60 hz

[Jacek]

I literally picked up a fan controller for a ceiling fan. I put it into a box and hooked up wire to it. One end plugs into the outlet other end has a female  end which the fan plugs into. I left a spot where I wired the fan controller to where I can Hooke in a voltage meter and see what voltage is at when the fan initially starts.

I then found what rpm the fan was turning at and did a precentage to make steps of speed at start speed, quarter, half,3/4, and full speed. All by using voltage reading on the multimeter.

Very cheap solution and is quite repeatable for fan speed when you hit those voltages. 

20 bucks is what I spent.

[yobasan]

I bought the fan controller that GregR and Susan linked above and used it. Also, I have never used a variac but I understand the theory.

First, I want to say I really hate using the knobs. Chaff build-up can clog it and the fan is super-powerful, almost an overkill so even a small adjustment leads to huge change in airflow.
What I wanted/expected from the fan controller was to leave the exhaust knobs completely open, and simply use the fan controller to control the airflow.
However, I found that to be impossible. Even at the lowest speed, the fan is still strong enough that I still have to close the exhaust knob a bit for the initial 2-3 minutes where i want the drum to be a bit humid, to make sure the internal temp of the beans are similar to external temp.

Yes, I agree with the experts here that PRECISE airflow is overrated and as long as you can manage to have a general low, mid, high, that's good.
but I'm not sure if low is really LOW. I think LOW with variac vs LOW with fan controller is going to be different. Low with fan controller is still (in my opinion) a bit high for the initial charge to 2-3min mark. At Variac 5%, you're really going to get 5%.

I don't know which variac you're looking up but one I found on amazon is $57
https://www.amazon.com/PHC-Enterprise-Variac-Variable-Transformer/dp/B006NGI2RS/ref=sr_1_2?ie=UTF8&qid=1497881261&sr=8-2&keywords=variac

You won't need anything above 5A. The fan at full speed would be OVERKILL anyway (i'm sure the experts would agree). You only need at most 50-60% of the fan power.

CONCLUSION:
If you want to mess with knobs and other mechanics besides the fan controller, buy the fan controller. that's what I'm doing now and it works okay.
If you don't want to mess with knobs and only use the fan controller to control the airflow -- buy a variac.

I would love to hear the opposite.
Maybe my fan controller is wonky and not giving me low enough speed.

Phil
ATL, GA

[SusanJoM]

Phil, you might want to invest in a cheap anemometer.  That would give you an opportunity to actually test the various controller settings and see how well the fan is responding, how high and how low it goes at what settings. 

I hardly mess with my fan settings during a roast, so I am not the one to advise you on 'how', but it seems as if you would have more confidence using the controller once you had air flow amounts that you could connect to each marker

Just a thought.
I had one.  I sold it.  I may end up getting another.  It's a useful little tool.

[yobasan]

Susan,

I actually don't mess with airflow much either (as of now) Ever since I got the fan controller, I've been putting at low setting and just adjust the knobs slightly. That is what I'm doing, but I'm not sure if that's what I should be doing.

Based on videos I saw of Mill City Roaster's Coffee of the Month series (in one episode, they use Huky 500J): They talk about how the fan setting should be low during drying, low-mid, during maillard, mid-high during cracks until drop. If I can get a wider range of controls for airflow, maybe my coffee can taste better?

Phil
ATL, GA

[SusanJoM]

So when you mention 'the knobs' you are talking about the damper control on the exhaust tube?
I just leave that wide open.  In fact I'm having it removed entirely from my J tube, although with the J there doesn't seem to be any trouble with clogging the way there is with the T. 

[yobasan]

Yes yes. Damper - that word escaped my brain for some reason.
Okay. I'm gonna try leaving everything open, and minaly adjust kPa for RoR.
Thank you and sorry for taking over the post. I guess we came back full circle in saying that variacs are not necessary.

Phil
ATL, GA

[Gregr]

Coming up on 3 years that I've been using that fan controller.
Personally I think a low setting on the fan is perfect- not too much at all. Once first crack is over I raise it up significantly but for the rest of the roast it stays right at 20%.
I look at the fan as an emergency brake slash nitrous slash bean evener   Awkward...
At high settings it can very quickly lower the temp in the drum and reduce the bean temp delta. At mid levels it can give big burst of heat and at a low setting [throughout] the beans roast very evenly- something I take for granted now but really appreciated coming from a Hottop and Behmor.
So what I'm saying is love it, use it- don't ignore it! But do ignore the damper- it's not needed with a decent fan controller.