Hi Guys,
I have a Fantech FG6 centrifugal fan I want to speed control. A simple resistive fan controller makes it hum, so I got a cheapo 3 speed fan controller with the anti-hum caps - https://www.lowes.com/pd/Lutron-Rotary-3-Speed-1-5-Amp-White-Indoor-Rotary-Fan-Control/3189381

My issue is the speed steps are not at 33/66/100%, High is 100%, medium is ~25%, and low is barely on, like 5 or 10%.

Since High is too high, but medium is too low. Can I rewire the low and medium or high and low caps together in parallel or series to combine them and make a 2 speed fan controller, like just high and medium?

Alternately, I have access to caps and a soldering iron at my work. If its somewhat easy I could make my own crude controller, but am unsure how voltage and frequency relate to the cap size or whatever prevents the hum. Is it easy enough to make a new one myself?

Im an idiot by the standards of this board, so please forgive my ignorance in advance. I took some electronics courses in high school, but that was quite a while ago.

Thanks for any help!

 

There is more to what the capacitors do in a ceiling fan than just setting the speed. You can buy a continuously variable control at GRAINGERS and set the speed exactly where you want it. Really though, the proportions described are far more reasonable that full, 2/3, and 1/3 speed.

And given your description of your skills, I suggest not getting in to the fan itself, since that may well lead to having it not working at all.

 

Start with 1uF and 2uF capacitors, @450VAC minimum, these work in my ceiling fan, 1uF is slow, 3uF is middle speed.

 

I have an old ceiling fan speed controller that the "Remote" part of it has failed. It's not practical for use in my home. However, I've found a use for it. I have a two speed squirrel cage (centrifugal) fan that it can be used to control. When I use Black/White (full speed) I can get the controller to give me three speeds. I assumed (yes, I said I assumed) that using the Red/White would give me slower speeds that would be "Three Speed" controllability. However, using Red/White, when on HIGH I get full speed. When on MEDIUM I get almost no flow at all. And on LOW - forget about it. Just wasting energy.

I use mine as a cat litter box vent to very gently pull air away from the box and exhaust it outside. Yes, my cat's liter box has a bathroom stink fan. The wife got upset when someone at work asked her if she had cats. The box is in the laundry room. I hate the sand everywhere, and in the laundry room is a place I rarely go. So that's where it will stay.

Given that I can get full or dead slow speeds, the fan is also useful for scooping the liter. You can turn it on full and it extracts the dust particles that are raised during sifting / scooping. Then return it to dead slow so it's not pulling all the hot air out of the house. In fact, it's in the basement just 12 inches above the floor. So it's barely pulling any air out - and what it pulls out is typically the colder air.

The point I should have made early on is that different motors will react differently with ceiling fan controllers. Someone already mentioned a full range fan speed controller. I have one on my wet fan. A fan with water misters that is used outside in the summer time to blow cooled air at a barbecue. The kids LOVE it. You can't get them out from in front of it without having to raise your voice at them. Then they just hate you for spoiling their fun.

 

I have a Fantech FG6 centrifugal fan I want to speed control. A simple resistive fan controller makes it hum, so I got a cheapo 3 speed fan controller with the anti-hum caps - https://www.lowes.com/pd/Lutron-Rotary-3-Speed-1-5-Amp-White-Indoor-Rotary-Fan-Control/3189381

Why not get the speed controller made for that fan by the company that makes the fan? https://shop.fantech.net/en-US/wc--15--speed--control--5a/p96450

You really shouldn't mess with other controllers on this. The motor in the fan is a single phase split capacitor motor, according to the makers website. Not all of them work well with the capacitor type speed controls.
Quote, "Motor:
Motorized impeller shall be an external rotor type, class B insulation, enclosed with permanent split capacitor"
From - https://shop.fantech.net/en-US/fg--6--centrifugal--inline--fan/p99702

 

Why not get the speed controller made for that fan by the company that makes the fan? https://shop.fantech.net/en-US/wc--15--speed--control--5a/p96450

You really shouldn't mess with other controllers on this. The motor in the fan is a single phase split capacitor motor, according to the makers website. Not all of them work well with the capacitor type speed controls.
Quote, "Motor:
Motorized impeller shall be an external rotor type, class B insulation, enclosed with permanent split capacitor"
From - https://shop.fantech.net/en-US/fg--6--centrifugal--inline--fan/p99702

Often an OEM part is the most expensive one that may be available. AND it may not provide the functioning that the user wants. I see that very frequently in my business. an adequately rated variable speed drive, correctly installed and wired, is a decent choice.
Keep in mind that ALL OEM DESIGNS are done with the primary goal of maximum PROFIT, not being the most satisfactory choice.

 

Thanks for the thoughts guys,

I actually have the exact fan controller you linked, however that is a simple resistive controller that makes the fan hum rather loudly, thus the root of this question. Kinda dumb that they recommend that one. From what I understand, a non-digital or non-capacitor'd infinitely variable fan controller will make a motor like this hum. so far my experience supports that.

The 3 speed controller from lutron (or others) does not hum, but the speed is too fast or slow.

I definitely would not mess with the fan itself.

I guess im asking, what do I need to modify to get more juice out of the controller? Less resistance? more capacitance? both? I read another thread on here where someone wired 2 caps in parallel or series to get an intermediate speed that the controller did not come wired as. I know a digital controller is really what I need, but I dont want to spend $90 for the one on amazon.

Thanks again

 

If the low speed and middle speed are too slow, then you need more capacitance..

Take pics of the capacitors and then we can work out what values to replace them with..

 

Thanks for the thoughts guys,

I actually have the exact fan controller you linked, however that is a simple resistive controller that makes the fan hum rather loudly, thus the root of this question. Kinda dumb that they recommend that one. From what I understand, a non-digital or non-capacitor'd infinitely variable fan controller will make a motor like this hum. so far my experience supports that.

The 3 speed controller from lutron (or others) does not hum, but the speed is too fast or slow.

I definitely would not mess with the fan itself.

I guess im asking, what do I need to modify to get more juice out of the controller? Less resistance? more capacitance? both? I read another thread on here where someone wired 2 caps in parallel or series to get an intermediate speed that the controller did not come wired as. I know a digital controller is really what I need, but I dont want to spend $90 for the one on amazon.

Thanks again

I am not aware of any "resistive" types of speed controllers available presently. There are SCR and TRIAC phase control sensors of quite a few varieties, and possibly some of those may cause a hum from some types of motors. The Grainger unit that I installed cost about $29, I think, but that was a while back, it may be more now. In addition, Home Depot offers a few different fan controls are repair parts. I did fix a HUNTER brand fan for a client by replacing the remote control set, which cost far less than the posted price of purchasing it direct from Hunter. It was much less than HALF their price.

 

I actually have the exact fan controller you linked, however that is a simple resistive controller that makes the fan hum rather loudly, thus the root of this question

If that was meant for me, that controller is a SCR based control, not a resistor one. Many times the "hum" in those inline fans is due to the length or bends/elbows in the piping, not the motor it's self.

Read what they say over here - https://forums.mikeholt.com/threads/speed-control-for-split-capacitor-motor.135938/